Avialae Gauthier, 1986
Official Definition- (Vultur gryphus <- Dromaeosaurus albertensis, Saurornithoides mongoliensis) (Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017; Benito, Chen, Wilson, Bhullar, Burnham and Field, 2022; Registration Number 552)
Other definitions- (Passer domesticus <- Deinonychus antirrhopus) (modified from Padian, 2004; modified from Gauthier, 1986)
(Archaeopteryx lithographica + Vultur gryphus) (modified from Wagner and Gauthier, 1999)
(feathered wings homologous with Vultur gryphus and used for powered flight) (Gauthier and de Queiroz, 2001)
(Passer domesticus <- Dromaeosaurus albertensis, Troodon formosus) (Maryanska, Osmolska and Wolsan, 2002)
(Vultur gryphus <- Deinonychus antirrhopus) (Zhang, Zhou, Xu, Wang and Sullivan, 2008)
(Passer domesticus <- Deinonychus antirrhopus, Troodon formosus) (modified from Hu, Hou, Zhang and Xu, 2009)
(Archaeopteryx lithographica + Passer domesticus) (modified from Agnolin and Novas, 2013)
(Passer domesticus <- Deinonychus antirrhopus, Stenonychosaurus inequalis) (Field, Benito, Chen, Jagt and Ksepka, 2020)
= "Avialae" Gauthier, 1984
= Ornithurae sensu Gauthier, 1986
Definition- (Passer domesticus <- Archaeopteryx lithographica) (Sereno, online 2005; modified)
= Orthavialae Ji, Ji, Zhang, You, Zhang, Wang, Yuan and Ji, 2002
= Avialae sensu Maryanska, Osmolska and Wolsan, 2002
Definition- (Passer domesticus <- Dromaeosaurus albertensis, Troodon formosus)
= Avialae sensu Zhang, Zhou, Xu, Wang and Sullivan, 2008
Definition- (Vultur gryphus <- Deinonychus antirrhopus)
= Avialae sensu Hu, Hou, Zhang and Xu, 2009
Definition- (Passer domesticus <- Deinonychus antirrhopus, Troodon formosus)
= Averaptora Agnolin and Novas, 2013
Definition- (Passer domesticus <- Dromaeosaurus albertensis) (modified)
= Eumaniraptora sensu Agnolin and Novas, 2013
Definition- (Passer domesticus <- Troodon formosus) (modified)
= Avialae sensu Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017
Definition- (Vultur gryphus <- Dromaeosaurus albertensis, Saurornithoides mongoliensis)
= Eumaniraptora sensu Lefevre, Cau, Cincotta, Hu, Chinsamy, Escuillie and Godefroit, 2017
Definition- (Passer domesticus <- Anchiornis huxleyi)
= Avialae sensu Field, Benito, Chen, Jagt and Ksepka, 2020
Definition- (Passer domesticus <- Deinonychus antirrhopus, Stenonychosaurus inequalis)
Comments- Orthavialae was proposed by Ji et al. (2002) in a cladogram as excluding Archaeopteryx, but including Shenzhouraptor, Jixiangornis and Pygostylia. The text has yet to be translated from Chinese, so it is unknown if the term is discussed further.
Ex-Avialae- Buffetaut et al. (2005) described four eggs from the Early Cretaceous Sao Khua Formation of Thailand as being from a non-ornithothoracine avialan, but Fernandez et al. (2012) determined they were actually from a squamate.
References- Gauthier, 1984. A cladistic analysis of the higher systematic categories of the Diapsida. PhD thesis. University of California. 564 pp.
Gauthier, 1986. Saurischian monophyly and the origin of birds. Memoirs of the Californian Academy of Sciences 8, 1-55.
Wagner and Gauthier, 1999. 1,2,3 5 2,3,4: A solution to the problem of the homology of the digits in the avian hand. Proceedings of the National Academy of Sciences. 96, 5111-5116.
Gauthier and de Quieroz, 2001. Feathered dinosaurs, flying dinosaurs, crown dinosaurs, and the name "Aves." In Gauthier and Gall (eds.). New Perspectives on the Origin and Early Evolution of Birds: Proceedings of the International Symposium in Honor of John H. Ostrom. Peabody Museum of Natural History. 7-41.
Ji, Ji, Zhang, You, Zhang, Wang, Yuan and Ji, 2002. A new avialian bird - Jixiangornis orientalis gen. et sp. nov. - from the Lower Cretaceous of Western Liaoning, NE China. Journal of Nanjing University (Natural Sciences). 38(6), 723-736.
Maryanska, Osmolska and Wolsan, 2002. Avialan status for Oviraptorosauria. Acta Palaeontologica Polonica. 47(1), 97-116.
Padian, 2004. Basal Avialae. In Weishampel, Dodson and Osmolska (eds.). The Dinosauria Second Edition. University of California Press. 210-231.
Buffetaut, Grellet-Tinner, Suteethorn, Cuny, Tong, Košir, Cavin, Chitsing, Griffiths, Tabouelle and Le Loeuff, 2005. Minute theropod eggs and embryo from the Lower Cretaceous of Thailand and the dinosaur-bird transition. Naturwissenschaften. 92, 477-482.
Sereno, online 2005. Stem Archosauria - TaxonSearch. http://www.taxonsearch.org/dev/file_home.php [version 1.0, 2005 November 7]
Zhang, Zhou, Xu, Wang and Sullivan, 2008. A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers. Nature. 455, 1105-1108.
Hu, Hou, Zhang and Xu, 2009. A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus. Nature. 461, 640-643.
Fernandez, Buffetaut, Maire, Adrien, Suteethorn and Tafforeau, 2012. Phase contrast synchrotron microtomography: Improving noninvasive investigations of fossil embryos in ovo. Microscopy and Microanalysis. 18(1), 179-185.
Agnolin and Novas, 2013. Avian ancestors: A review of the phylogenetic relationships of the theropods Unenlagiidae, Microraptoria, Anchiornis and Scansoriopterygidae. Springer Netherlands. 96 pp.
Cau, Beyrand, Voeten, Fernandez, Tafforeau, Stein, Barsbold, Tsogtbaatar, Currie and Godefroit, 2017. Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs. Nature. 552, 395-399.
Lefevre, Cau, Cincotta, Hu, Chinsamy, Escuillie and Godefroit, 2017. A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers. The Science of Nature. 104:74.
Field, Benito, Chen, Jagt and Ksepka, 2020. Late Cretaceous neornithine from Europe illuminates the origins of crown birds. Nature. 579, 397-401.
Benito, Chen, Wilson, Bhullar, Burnham and Field, 2022. Forty new specimens of Ichthyornis provide unprecedented insight into the postcranial morphology of crownward stem group birds. PeerJ. 10:e13919.

undescribed Avialae (Mohr and Currie, 2015)
Early Campanian, Late Cretaceous
Milk River Formation, Alberta, Canada
Material- teeth
Reference- Mohr and Currie, 2015. The development of bird teeth from the Late Cretaceous of Alberta. Journal of Vertebrate Paleontology. Program and Abstracts 2015, 182.

undescribed possible Avialae (Peng, Russell and Brinkman, 2001)
Middle Campanian, Late Cretaceous
Foremost Formation of the Belly River Group, Alberta, Canada
Material- (RTMP 96.62 coll.) six teeth (Peng, Russell and Brinkman, 2001)
(RTMP 2003.89.33) tooth (Brinkman, Braman, Neuman, Ralrick and Sato, 2005)
(?UC coll.) tooth (Frampton, 2006)
Comments- Cullen and Evans (2016) list one "Aves indet." tooth from the PHRN site, which equates with Frampton's (2006) thesis.
References- Peng, Russell and Brinkman, 2001. Vertebrate microsite assemblages (exclusive of mammals) from the Foremost and Oldman Formations of the Judith River Group (Campanian) of southeastern Alberta: An illustrated guide. Provincial Museum of Alberta Natural History Occasional Paper. 25, 54 pp.
Brinkman, Braman, Neuman, Ralrick and Sato, 2005. A vertebrate assemblage from the marine shales of the Lethbridge Coal Zone. In Currie and Koppelhus (eds.). Dinosaur Provincial Park: A spectacular ancient ecosystem revealed. Indiana University Press. 486-500.
Frampton, 2006. Taphonomy and palaeoecology of mixed invertebrate-vertebrate fossil assemblage in the Foremost Formation (Cretaceous, Campanian), Milk River Valley, Alberta. Masters thesis, University of Calgary. 294+ pp.
Cullen and Evans, 2016. Palaeoenvironmental drivers of vertebrate community composition in the Belly River Group (Campanian) of Alberta, Canada, with implications for dinosaur biogeography. BMC Ecology. 16, 52.

unnamed possible Avialae (Sankey and Brinkman, 2000)
Late Campanian, Late Cretaceous
Dinosaur Park Formation of the Belly River Group, Alberta, Canada
Material- *(RTMP 84.92.205) tooth (2.7 mm) (Sankey et al., 2002)
*(RTMP 86.21.68) tooth (3.7 mm) (Sankey et al., 2002)
*(RTMP 86.30.39; = RTMP 86.172.53 of Sankey et al., 2002) tooth (2.9 mm) (Sankey et al., 2002)
(RTMP 86.45.27) tooth (3.7 mm) (Sankey et al., 2002)
(RTMP 86.52.54) tooth (4.7 mm) (Sankey et al., 2002)
(RTMP 87.4.19) tooth (5.5 mm) (Sankey et al., 2002)
(RTMP 87.4.46) tooth (3.6 mm) (Sankey et al., 2002)
(RTMP 87.20.8) tooth (4.3 mm) (Sankey et al., 2002)
(RTMP 87.30.10) tooth (~3.7 mm) (Sankey et al., 2002)
*(RTMP 87.158.76) tooth (3.3 mm) (Sankey et al., 2002)
(RTMP 87.158.77) tooth (3.1 mm) (Sankey et al., 2002)
(RTMP 88.11.65) tooth (2.9 mm) (Sankey et al., 2002)
(RTMP 95.145.34a) tooth (2.1 mm) (Sankey et al., 2002)
(RTMP 95.145.34b) tooth (4 mm) (Sankey et al., 2002)
(RTMP 95.145.34c) tooth (3.5 mm) (Sankey et al., 2002)
(RTMP 95.147.30) tooth (2.4 mm) (Sankey et al., 2002)
(RTMP 95.151.21) tooth (2.3 mm) (Sankey et al., 2002)
*(RTMP 95.174.52) tooth (2.3 mm) (Sankey et al., 2002)
*(RTMP 95.177.79) tooth (3 mm) (Sankey et al., 2002)
(RTMP 95.180.49) tooth (3.2 mm) (Sankey et al., 2002)
(RTMP 95.181.10a) tooth (3.1 mm) (Sankey et al., 2002)
(RTMP 95.181.10b) tooth (3.3 mm) (Sankey et al., 2002)
*(RTMP 95.181.10c) tooth (3.3 mm) (Sankey et al., 2002)
(RTMP 95.181.10d) tooth (3.3 mm) (Sankey et al., 2002)
*(RTMP 95.181.60e) tooth (2.4 mm) (Sankey et al., 2002)
*(RTMP 95.181.60f) tooth (2.5 mm) (Sankey et al., 2002)
(RTMP 96.12.40) tooth (Dumont et al., 2016)
(RTMP 96.62.51) tooth (3.2 mm) (Sankey et al., 2002)
(RTMP 96.62.62) tooth (3.5 mm) (Sankey et al., 2002)
(RTMP 96.62.62a) tooth (3.8 mm) (Sankey et al., 2002)
(RTMP 96.62.62b) tooth (2.7 mm) (Sankey et al., 2002)
Comments- The CMN vertebra was identified by Lambe (1902) as a posterior dorsal tentatively referred to Struthiomimus (his Ornithomimus altus) (plate XV figure 6-8), but is actually a caudal, and may be Troodon or Saurornitholestes based on its low square articular face, amphicoelous centrum and lack of a pleurocoel.
The RTMP teeth are distinguished from other Dinosaur Park theropods by their small size, constricted bases, slight recurvature, and general absence of serrations. Distal serrations are present in about a fourth of the sample (indicated by asterisks above) and are tiny (>8/mm), while minute mesial serrations are only present in one tooth (RTMP 89.103.25). About half have distinct carinae. Some resemble Mononykus except for their concave distal edge. Others most closely resemble hesperornithines, as noted by Sankey et al. (2002). Those authors referred the teeth to Aves indet., but also noted Microraptor has similar teeth. However, neither alvarezsauroids nor avialans (except for Longipteryx) have been reported to have serrations. Microraptor has highly heterodont dentition where the anterior serrationless teeth are more recurved and lack a basal constriction, while the posterior teeth are similar except in having slightly larger serrations (8/mm).  They may belong to juvenile Richardoestesia instead, which these teeth grade into.
References- Sankey and Brinkman, 2000. New theropod and bird teeth from the Late Cretaceous (Campanian) Judith River Group, Alberta. Journal of Vertebrate Paleontology. 20(3), 67A.
Sankey, Brinkman, Guenther and Currie, 2002. Small theropod and bird teeth from the Late Cretaceous (Late Campanian) Judith River Group, Alberta. Journal of Paleontology. 76(4), 751-763.
Mohr and Currie, 2015. The development of bird teeth from the Late Cretaceous of Alberta. Journal of Vertebrate Paleontology. Program and Abstracts 2015, 182.
Dumont, Tafforeau, Bertin, Bhullar, Field, Schulp, Strilisky, Thivichon-Prince, Viriot and Louchart, 2016. Synchrotron imaging of dentition provides insights into the biology of Hesperornis and Ichthyornis, the "last" toothed birds. BMC Evolutionary Biology. 16:178.

unnamed avialan (Fanti and Miyashita, 2009)
Late Campanian, Late Cretaceous
Wapiti Formation, Alberta, Canada
Material- (RTMP 2004.93.4) tooth
Comments- This was referred to a bird by Fanti and Miyashita (2009).
Reference- Fanti and Miyashita, 2009. A high latitude vertebrate fossil assemblage from the Late Cretaceous of west-central Alberta, Canada: Evidence for dinosaur nesting and vertebrate latitudinal gradient. Palaeogeography, Palaeoclimatology, Palaeoecology. 275, 37-53.

unnamed Avialae (Larson, Brinkman and Bell, 2010)
Early Maastrichtian, Late Cretaceous
Horseshoe Canyon Formation, Alberta, Canada
Material- (RTMP 2000.45.52) tooth (Larson, Brinkman and Bell, 2010)
(RTMP 2000.45.57) tooth (Larson, Brinkman and Bell, 2010)
(RTMP 2003.57.2) tooth (Larson, Brinkman and Bell, 2010)
(RTMP or UALVP coll.) quadrate (Eberth and Currie, 2010)
two teeth (Larson, Brinkman and Bell, 2010)
References- Eberth and Currie, 2010. Stratigraphy, sedimentology, and taphonomy of the Albertosaurus bonebed (upper Horseshoe Canyon Formation; Maastrichtian), southern Alberta, Canada. Canadian Journal of Earth Sciences. 47(9), 1119-1143.
Larson, Brinkman and Bell, 2010. Faunal assemblages from the upper Horseshoe Canyon Formation, an Early Maastrichtian cool-climate assemblage from Alberta, with special reference to the Albertosaurus sarcophagus bonebed. Canadian Journal of Earth Sciences. 47(9), 1159-1181.

undescribed Avialae (Tokaryk, Cumbaa and Storer, 1997)
Middle Cenomanian, Late Cretaceous
Carrot River, Belle Fourche Member of the Ashville Formation, Saskatchewan, Canada
Material- (RSM coll.) four fused synsacral vertebrae, several coracoids, proximal carpometacarpus, three pelvic elements, many fragments (Tokaryk et al., 1997)
Middle Cenomanian, Late Cretaceous
Bainbridge River, Belle Fourche Member of the Ashville Formation, Saskatchewan, Canada
(RSM P2526.1) jaw element (Sanchez, 2010)
(RSM P2831.13) phalanx (Sanchez, 2010)
(RSM P2831.19) dentary (Sanchez, 2010)
(RSM P2987.23) phalanx (Sanchez, 2010)
?(RSM P2988.4) proximal tarsometatarsus (Sanchez, 2010)
(RSM P2995.6) beak (Sanchez, 2010)
(RSM P2997.36) frontal (Sanchez, 2010)
Comments- Tokaryk et al. (1997) note many unidentified bird elements from the Carrot River bonebed, including three pelvic elements which may belong to Pasquiaornis.
Cumbaa et al. (2006) mention numerous bird remains from the Bainbridge River bonebed, some of which are probably not Pasquiaornis.  Sanchez (2010) lists as Aves- jaw element RSM P2526.1 which has teeth in sockets instead of grooves unlike hesperornithines; phalanges RSM P2831.13 and P2987.23 which are "very small"; dentary RSM P2831.19; tarsometatarsus RSM P2988.4 which is "very skinny"; and "beak" RSM P2995.6.
References- Tokaryk, Cumbaa and Storer, 1997. Early Late Cretaceous birds from Saskatchewan, Canada: the oldest diverse avifauna known from North America. Journal of Vertebrate Paleontology. 17(1), 172-176.
Cumbaa, Schr�der-Adams, Day and Phillips, 2006. Cenomanian bonebed faunas from the northeastern margin, Western Interior Seaway. In Lucas and Sullivan (eds). Late Cretaceous Vertebrates from the Western Interior. New Mexico Museum of Natural History and Science Bulletin. 35, 139-155.
Sanchez, 2010. Late Cretaceous (Cenomanian) Hesperornithiformes from the Pasquia Hills, Saskatchewan, Canada. Masters thesis, Carleton University. 238 pp.

undescribed avialan (Parsons and Parsons, 2007)
Late Aptian, Early Cretaceous
Cloverly Formation, Montana
Material- (MCZ or MOR coll. in part) manual phalanx
Comments- This and possibly referrable fragments were found as gut contents in a Deinonychus specimen, either MCZ 8791 or MOR 1178.
Reference- Parsons and Parsons, 2007. Avian-like manual phalanx found within gut contents of Lower Cretaceous dromaeosaurid: New data on the feeding behavior of Deinonychus antirrhopus (Saurischia: Theropoda). Journal of Vertebrate Paleontology. 27(3), 128A.

undescribed Avialae (Kirkland et al., 1997)
Cenomanian-Early Turonian, Late Cretaceous
Mussentuchit Member of the Cedar Mountain Formation, Utah, US
Material- (NCSM 33299) tooth (Avrahami, Gates, Heckert, Makovicky and Zanno, 2018)
(NCSM 33300) tooth (Avrahami, Gates, Heckert, Makovicky and Zanno, 2018)
(NCSM 33308) tooth (2.75x1.39x0.85 mm) (Avrahami, Gates, Heckert, Makovicky and Zanno, 2018)
(OMNH 28735) tooth (Avrahami, Gates, Heckert, Makovicky and Zanno, 2018)
(OMNH 28736) tooth (Avrahami, Gates, Heckert, Makovicky and Zanno, 2018)
(OMNH 28737) tooth (Avrahami, Gates, Heckert, Makovicky and Zanno, 2018)
teeth (Kirkland et al., 1997)
Comments- Kirkland et al. (1997) listed Aves order indet., while Cifelli et al. (1999) noted two Avialae dental morphs, one referrable to Hesperornithes and one not. Avrahami et al. (2016) "tentatively identify two teeth as Avialae indet., possibly representing a hesperornithiform", which were described as NCSM 33299 and 33300 by Avrahami et al. (2018).  OMNH 28735-28737 were stated to be "similar in morphology and size" and may represent teeth noted by Cifelli et al..   NCSM 33308 was referred to ?Paronychodon by Avrahami et al. (2018), but lacks longitudinal ridges, so is placed here instead given its lack of serrations and constricted base.
References- Kirkland, Britt, Burge, Carpenter, Cifelli, DeCourten, Eaton, Hasiotis and Lawton, 1997. Lower to Middle Cretaceous dinosaur faunas of the Central Colorado Plateau: a key to understanding 35 million years of tectonics, sedimentology, evolution, and biogeography. Brigham Young University Geology Studies. 42, 69-103.
Cifelli, Nydam, Gardner, Weil, Eaton, Kirkland, Madsen, 1999. Medial Cretaceous vertebrates from the Cedar Mountain Formation, Emery County, Utah: the Mussentuchit Local Fauna. in Gillette (ed.). Vertebrate Paleontology in Utah. Utah Geological Survey, Miscellaneous Publication. 99-1, 219-242.
Avrahami, Humphrey, Heckert, Gates, Makovicky and Zanno, 2016. The early Late Cretaceous paleofaunal vertebrate assemblage of the Cliffs of Insanity microsite in the Mussentuchit Member of the Cedar Mountain Formation, Utah. Journal of Vertebrate Paleontology. Program and Abstracts, 90.
Avrahami, 2018. Paleobiodiversity of a new microvertebrate locality from the Upper Cretaceous Mussentuchit Member, Cedar Mountain Formation, Utah: Testing morphometric multivariate approaches for quantifying shape variation in microvertebrate specimens. Masters thesis, North Carolina State University. 181 pp.
Avrahami, Gates, Heckert, Makovicky and Zanno, 2018. A new microvertebrate assemblage from the Mussentuchit Member, Cedar Mountain Formation: Insights into the paleobiodiversity and paleobiogeography of early Late Cretaceous ecosystems in western North America. PeerJ. 6:e5883.

undescribed avialan (Tykoski and Fiorillo, 2007)
Middle Cenomanian, Late Cretaceous
Woodbine Formation, Texas, US
Material- scapula, manual phalanx II-1, partial limb element, fragments
Reference- Tykoski and Fiorillo, 2007. Avian remains and other vertebrates from a new locality in the Woodbine Formation (Middle Cenomanian) of north-central Texas. Journal of Vertebrate Paleontology. 27(3), 161A.

unnamed Avialae (Bell and Everhart, 2011)
Late Cenomanian, late Cretaceous
Lincoln Limestone Member of the Greenhorn Limestone Formation, Kansas, US
Material- (FHSM VP-17458) proximal femur
(FHSM VP-17461) maxillary fragment, dentary fragment
Comments- Bell and Everhart (2011) described these as Aves indet..
Reference- Bell and Everhart, 2011. Remains of small ornithurine birds from a Late Cretaceous (Cenomanian) microsite in Russell County, north-central Kansas. Transactions of the Kansas Academy of Science. 114(1-2), 115-123.

undescribed avialan (Rivera-Sylva, Frey, Stinnesbeck, Padilla Gutierrez, Gonzalez Gonzalez and Amezcua Torres, 2015)
Late Campanian, Late Cretaceous
Cerro del Pueblo Formation, Mexico
Comments- Said to be "remains of a small bird."
Reference- Rivera-Sylva, Frey, Stinnesbeck, Padilla Gutierrez, Gonzalez Gonzalez and Amezcua Torres, 2015. The Late Cretaceous Las Aguilas dinosaur graveyard, Coahuila, Mexico. Journal of Vertebrate Paleontology. Program and Abstracts 2015, 203.

unnamed possible Avialae (Seeley, 1869)
Late Albian, Early Cretaceous
Cambridge Greensand, England
Material- ?(BGS 87931) (juvenile) first sacral vertebra (8.5 mm) (Galton and Martin, 2002b)
?(BGS 87933) proximal femur (Galton and Martin, 2002b)
(SMC B55274) dorsal vertebra (7.4 mm) (Seeley, 1869)
(SMC B55278) dorsal vertebra (10.1 mm) (Seeley, 1869)
(SMC B55280) dorsal vertebra (8.5 mm) (Seeley, 1869)
?(SMC B55328) proximal coracoid (Seeley, 1869)
(YORYMG 584) posterior cervical vertebra (9.3 mm) (Seeley, 1876)
Comments- SMC B55274, 55278 and 55280 are three of the four dorsal vertebrae listed as "Enaliornis" by Seeley (1869). SMC B55274 (mistyped B55279 in the figures of Galton and Martin, 2002b) and B55280 are dorsal vertebrae referred to Enaliornis sedgwicki by Seeley (1876), while YORYMG 584 was identified as an Enaliornis dorsal vertebra by Seeley. As they differ from hesperornithines, they were placed in Avialae incertae sedis by Galton and Martin (2002a, b) along with SMC B55278. Galton and Martin (2002b) tentatively referred the sacral vertebra BGS 87931 and proximal femur BGS 87933 to the same taxon. SMC B55328 was stated to be a proximal coracoid by Seeley (1869), and while possibly true, Galton and Martin (2002b) exclude it from Hesperornithes. This will be redescribed by Galton (in prep.). Galton et al. (2009) refer it all of this material to Aves indet..
References- Seeley, 1869. Index to the fossil remains of Aves, Ornithosauria and Reptilia, from the Secondary System of strata arranged in the Woodwardian Museum of the University of Cambridge. Deighton, Bell & Co., Cambridge. 143 pp.
Seeley, 1876. On the British fossil Cretaceous birds. Quarterly Journal of the Geological Society of London. 32, 496-515.
Galton and Martin, 2002a. Enaliornis, an Early Cretaceous hesperornithiform bird from England, with comments on other Hesperornithiformes. In Chiappe and Witmer (eds). Mesozoic birds: Above the heads of dinosaurs. Berkeley: University of California Press. 317-338.
Galton and Martin, 2002b. Postcranial anatomy and systematics of Enaliornis Seeley, 1876, a footpropelled diving bird (Aves: Ornithurae: Hesperornithiformes) from the Early Cretaceous of England. Revue de Paleobiologie. 21(2), 489-538.
Galton, Dyke and Kurochkin, 2009. Re-analysis of Lower Cretaceous fossil birds from the UK reveals an unexpected diversity. Journal of Vertebrate Paleontology. 29(3), 102A.
Galton, in prep. Additional bird bones (Hesperornithiformes Enaliornis and Aves incertae sedis) from the Early Cretaceous of England. Revue Paleobiologie.

undescribed avialan (Vidal, 1902)
Late Berriasian-Early Barremian, Early Cretaceous
La Pedrera de Rubies Lithographic Limestones Formation, Spain
Material- (destroyed) skeleton
Comments- Vidal (1902) mentioned the accidental destruction of a fossil bird, which based on provenence may belong to Noguerornis or the unnamed La Pedrera juvenile enantiornithine taxon.
Reference- Vidal, 1902. Sobre la presencia del tramo Kimeridgense del Montsech y hallazgo de un batracio en sus hiladas. Memorias de la Real Academia de Ciencias y Artes de Barcelona. 4(18), 263-267.

undescribed possible avialan (Buffetaut, Pereda-Suberbiola and Corral, 2006)
Late Campanian, Late Cretaceous
La�o, Sedano Formation, Spain
Material- (MCNA coll.) tibiotarsus
Reference- Buffetaut, Pereda-Suberbiola and Corral, 2006. A bird-like tibiotarsus from the Late Cretaceous of La�o (Iberian Peninsula). 54th Symposium of Vertebrate Palaeontology and Comparative Anatomy. 4-5.

unnamed Avialae (Osi, 2004)
Santonian, Late Cretaceous
Csehbanya Formation, Hungary
Material- (MTM V.2002.05) (juvenile) distal femur
(MTM V.2003.19) distal metatarsal III
Comments- These were briefly described as enantiornithines by Osi (2004), but later placed more generally as non-avian birds by him in 2008 when they were described in detail.
References- Osi, 2004. Enantiornithine bird remains from the Late Cretaceous of Hungary. Sixth International Meeting of the Society of Avian Palaeontology and Evolution, Abstracts. 50.
Osi, 2008. Enantiornithine bird remains from the Late Cretaceous of Hungary. Oryctos. 7, 55-60.

unnamed possible avialan (Zernezky, 1958)
Early Cretaceous
Tete-Oba, Ukraine
Material- hindlimb (pedal digit III 50 mm)
Comments- Zernezky (1958) described this as a bird with narrow pedal digits and a very short hallux. He considered it to have ralliform affinities, but it has not been studied subsequently
Reference- Zernezky, 1958. Enigmatic imprint. Nature (Moscow). 4, 113.

undescribed possible avialan (Unwin and Matsuoka, 2000)
Valanginian-Hauterivian, Early Cretaceous
Kuwajima Formation of the Tetori Group, Japan
Material- (SBEI 1221) posterior mandible
Comments- This was figured by Unwin and Matsuoka (2000) as an "avian? right articular."
Reference- Unwin and Matsuoka, 2000. Pterosaurs and birds. In Matsuoka (ed.). Fossils of the Kuwojima "Kasekikabe" (Fossil-bluff): Scientific report on a Neocomian (Early Cretaceous) fossil assembrage from the Kuwajima Formation, Tetori Group, Shiramine, Ishikawa, Japan. Shiramine Village Board of Education, Ishikawa. 99-104.

unnamed Avialae (Forster and O'Connor, 2000)
Middle Maastrichtian, Late Cretaceous
Anembalemba Member of Maevarano Formation, Madagascar
Material- (FMNH PA 749; Humeral Taxon F) incomplete humerus (~19 mm) (O'Connor and Forster, 2010)
(FMNH PA 751) proximal radius (O'Connor and Forster, 2010)
(UA 9610) incomplete metatarsal I (O'Connor and Forster, 2010)
(UA 9611) incomplete metatarsal I (O'Connor and Forster, 2010)
Comments- Forster and O'Connor (2000) reported a bird dentary, though this has not been mentioned in subsequent publications and has since been reidentified (O'Connor, pers. comm. 2014). The humerus FMNH PA 749 was assigned to Avialae indet. by O'Connor and Forster (2010). The latter authors do not assign the radius or metatarsals I to a taxon more exact than Avialae, though they do state the metatarsals lack the enantiornithine J-shape.
References- Forster and O'Connor, 2000. The avifauna of the Upper Cretaceous Maevarano Formation, Madagascar. Journal of Vertebrate Paleontology. 20(3), 41A-42A.
O'Connor and Forster, 2010. A Late Cretaceous (Maastrichtian) avifauna from the Maevarano Formation, Madagascar. Journal of Vertebrate Paleontology. 30(4), 1178-1201.

undescribed avialan (Close and Vickers-Rich, 2009)
Aptian, Early Cretaceous
Wonthoggi Formation of the Strzelecki Group, Victoria, Australia
Material- ulna
Reference- Close and Vickers-Rich, 2009. Australia's Mesozoic birds: New material from the Early Cretaceous of Victoria. Journal of Vertebrate Paleontology. 29(3), 80A.

unnamed possible avialan (Molnar, 1999)
Albian, Early Cretaceous
Griman Creek Formation, New South Wales, Australia
Material- (AM F103590) proximal tibiotarsus (5.9x4.6 mm)
Comments- This specimen is less derived than euornithines except for Patagopteryx in lacking a medial cnemial crest. The proximal surface is not round, unlike most enantiornithines. Molnar excluded non-bird theropods based on the lack of cnemial crest curvature and poorly developed condyles. Unfortunately, good comparative material for basal birds is lacking.
Reference- Molnar, 1999. Avian tibiotarsi from the Early Cretaceous of Lightning Ridge, N.S.W. In Tomida, Rich and Rich (eds). Proceedings of the Second Gondwanan Dinosaur Symposium, National Sciences Museum Monographs. 15, 197-209.

undescribed possible Avialae (Casal, Mart�nez, Luna and Ibiricu, 2016)
Coniacian-Maastrichtian, Late Cretaceous
Lago Colhue Huapi Formation, Chubut, Argentina
Material- (UNPSJB-PV 1049) fragmentary material
Comments- Casal et al. (2016) listed a specimen as (translated) "Ave indet., fragmentary remians", as did Ibiricu et al. (2020) despite describing most other Lago Colhue Huapi tetrapod material.  Lamanna et al. (2019) state "the identification of this fossil is tentative (GAC pers. obs. 2018)."
References- Casal, Mart�nez, Luna and Ibiricu, 2016. Ordenamiento y caracterizaci�n faun�stica del Cret�cico Superior del Grupo Chubut, Cuenca del Golfo San Jorge, Argentina. Revista Brasileira de Paleontologia. 19, 53-70.
Lamanna, Casal, Ibiricu and Mart�nez, 2019. A new peirosaurid crocodyliform from the Upper Cretaceous Lago Colhu� Huapi Formation of central Patagonia, Argentina. Annals of Carnegie Museum. 85, 193-211.
Ibiricu, Casal, Martinez, Alvarez and Poropat, 2020 (online 2019). New materials and an overview of Cretaceous vertebrates from the Chubut Group of the Golfo San Jorge Basin, central Patagonia, Argentina. Journal of South American Earth Sciences. 98, 102460.

Fortipesavis Clark and O'Connor, 2021
F. prehendens Clark and O'Connor, 2021
Early Cenomanian, Late Cretaceous
Angbamo, Myanmar
Holotype- (YLSNHM01001) skin of distal pes, scutellae, pedal claw sheath, contour feathers, retrix, remige or retrix
Diagnosis- (after Clark and O'Connor, 2021) mediolateral width of digit IV greater than digit III, and that of digit III greater than that of digit II, such that the mediolateral width of digit IV is twice that of digit II; plantar pads of digit IV mediolaterally wider than they are craniocaudally long and located between phalangeal joints; exaggerated plantar pads of digit IV separated by deep clefts; digit II ungual long, recurved and sharply tapered.
(suggested) pedal phalanx IV-4 shorter than IV-1.
Comments- Xing et al. (2019b) describe a foot without preserved bones and rachis-dominated retrix.  The latter indicate this is an avialan, but their referral of the specimen to Enantiornithes seems premature.  The authors wrote in digit II "The ungual sheath is long, recurved, and laterally compressed", which is true in all paravians, and in digit IV "The first phalanx appears to be the longest, followed by three shorter and subequal phalanges", which is actually not true of most enantiornithines that have phalanx IV-4 longest instead.  Xu et al. further suggest the identification "is further supported by the presence of an RDF in the surrounding amber and SSFs on the surface of the foot, as these two feather types have only been found together in the Enantiornithes", but SSFs (scutellate scale filaments) cannot generally be identified in traditionally preserved specimens and only enantiornithine feet have been discovered in amber prior to this.  Similarly, "that Enantiornithes is the only clade documented in the Hukawng avifauna thus far" is not strong evidence since all well-sampled avifaunas from around this time also preserve euornithines and non-ornithothoracines like confuciusornithids.  As enantiornithines universally have a more slender digit IV than II or III, this may be more parsimoniously another kind of avialan.
References- Xing, McKellar, O'Connor, Niu and Mai, 2019. A mid-Cretaceous enantiornithine foot and tail feather preserved in Burmese amber. Scientific Reports. 9:15513.
Clark and O'Connor, 2021. Exploring the ecomorphology of two Cretaceous enantiornithines with unique pedal morphology. Frontiers in Ecology and Evolution. 9:654156.

Praeornithes Rautian, 1978
Praeornithiformes Rautian, 1978
Praeornithidae Rautian, 1978
Praeornis Rautian, 1978
P. sharovi Rautian, 1978
Oxfordian, Late Jurassic
Karabastau (= Balabansai) Formation, Kazakhstan
Holotype- (PIN 2585/32) retrix
Referred- ?(ZPAL V 32/967) feather? (Dzik, Sulej and Niedzwiedzki, 2010)
Comments- Discovered in 1971, Sharov labeled the holotype specimen 'Praeornis'. Rautian later (1978) described this as the feather of a basal bird, naming it Praeornis sharovi. He assigned it its own subclass (Praeornithes), believing it to be more basal than Archaeopteryx due to the lack of barbules, and the medullary cavity in the barbs. Rautian also created the redundant order and family Praeornithiformes and Praeornithidae for the taxon (not to be confused with Kurochkin's 1995 Praeornithurae, which was erected for Protoavis). Bock (1986) stated it was more similar to a cycad leaf, and Burakova and Nessov (in Nessov, 1992) thought that it was identical to the contemporaneous cycad species Cycadites saportae. They thus synonymized the species. Doludenko et al. (1990) found it was comparable to the leaves of Paracycas harrisii and similarly concluded it was a cycad. Glazunova et al. (1991) used scanning electron microscopy to show it was not a plant and that the microstructure showed some resemblence to ratite feathers.  A specimen found in 2006 (ZPAL V 32/967) was referred to Praeornis by Dzik et al. (2010), but Agnolin et al. (2019) felt that "due to some morphological differences [they] are probably not the same taxon."  Dzik et al. found ZPAL V 32/967 differs from plant fossils in preservation and carbon isotope values, but also differs from feathers in having three vanes, an expanded distal tip to the shaft, and lack of basal narrowing. Agnolin et al. convincingly compared retrices of the holotype to Cratoavis to the Praeornis holotype, showing the latter is a rachis-dominated feather.  As these are limited to Epidexipteryx, confuciusornithiforms and enantiornithines, Praeornis is assigned here to Avialae. 
References- Rautian, 1978a. Unikal'noye pero ptitsy iz otlozheniy yurskogo ozera v khrebte Karatau. Paleontologicheskii Zhurnal. 4, 106-114.
Rautian, 1978b. A unique bird feather from Jurassic lake deposits in the Karatau. Paleontological Journal. 4, 520-528.
Bock 1986. The arboreal origin of avian flight. In Padian (ed.). The Origin of Birds and the Evolution of Flight. California Academy of Sciences. Memoir 8, 57-72.
Doludenko, Sakulina and Ponomarenko, 1990. Geology of the unique deposits of the fauna and flora from the Late Jurassic of Aulie (Karatau, South Kazakhstan). Academy of Sciences of the USSR, Geological Institute. [pp].
Glazunova, Rautian and Filin, 1991. Praeornis sharovi: Bird feather or plant leaf? Materialy 10 Vsesoyuznoi Ornitologicheskoi Konferentzii, Vitebsk. Part 2(1), 149-150.
Nessov, 1992. Mesozoic and Paleogene birds of the USSR and their paleoenvironments. in Campbell (ed). Papers in Avian Paleontology Honoring Pierce Brodkorb. Natural History Museum of Los Angeles County Science Series. 36, 465-478.
Kurochkin, 1995. Synopsis of Mesozoic Birds and Early Evolution of Class Aves. Archaeopteryx. 13, 47-66. 
Dzik, Sulej and Niedzwiedzki, 2010. Possible link connecting reptilian scales with avian feathers from the early Late Jurassic of Kazakstan. Historical Biology. 22(4), 394-402.
Agnolin, Rozadilla and de Souza Carvalho, 2019 (online 2017). Praeornis sharovi Rautian, 1978 a fossil feather from the early Late Jurassic of Kazakhstan. Historical Biology. 31(7), 962-966.

Scansoriopterygidae Czerkas and Yuan, 2002
Definition- (Scansoriopteryx heilmanni <- Dromaeosaurus albertensis, Oviraptor philoceratops, Passer domesticus) (proposed)
Other definitions- (Epidexipteryx hui + Epidendrosaurus ningchengensis) (Godefroit, Cau, Hu, Escuillie, Wu and Dyke, 2013; modified from Zhang et al., 2008)
(Epidendrosaurus ningchengensis <- Dromaeosaurus albertensis, Passer domesticus) (modified from Godefroit, Demuynck, Dyke, Hu, Escuillie and Claeys, 2013)
(Epidendrosaurus ningchengensis, Ambopteryx longibrachium <- Dromaeosaurus albertensis, Oviraptor philoceratops, Passer domesticus) (Wang, O'Connor, Xu and Zhou, 2019)
= Scansoriopterygidae sensu Godefroit, Demuynck, Dyke, Hu, Escuillie and Claeys, 2013
Definition - (Epidendrosaurus ningchengensis <- Dromaeosaurus albertensis, Passer domesticus) (modified)
Diagnosis- (after Zhang et al., 2008) dentary toothed only anteriorly; pubic peduncle of ilium subequal in size to ischial peduncle; pubis propubic; pubic boot absent; ischium longer than pubis; ischial shaft curved dorsally; ischium distally wide.
Comments- Note all published definitions break Phylocode Article 11.10 ("when a clade name is converted from a preexisting name that is typified under a rank-based code or is a new or converted name derived from the stem of a typified name, the definition of the clade name must use the type species of that preexisting typified name or of the genus name from which it is derived (or the type specimen of that species) as an internal specifier").
These have been most recently recovered as non-ornithine avialans (Senter et al., 2012), basal avialans closer to birds than Archaeopteryx (Foth et al., 2014; Lee et al., 2014), or basal paravians (Xu et al., 2015). Turner et al. (2012) found Epidexipteryx to be a basal paravian and Scansoriopteryx a non-ornithine avialan, though the former moves to basal oviraptorosaurs with one step and basal Avialae with two. Forcing the two to combine places Scansoriopterygidae in non-ornithine Avialae and takes four more steps. The derivative study of Brusatte et al. (2014) recovered Epidexipteryx as a basal oviraptorosaur.
References- Czerkas and Yuan, 2002. An arboreal maniraptoran from Northeast China. Feathered Dinosaurs and the Origin of Flight. The Dinosaur Museum Journal. 1, 63-95.
Zhang, Zhou, Xu, Wang and Sullivan, 2008. A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers. Nature. 455, 1105-1108.
Senter, Kirkland, DeBlieux, Madsen and Toth, 2012. New dromaeosaurids (Dinosauria: Theropoda) from the Lower Cretaceous of Utah, and the evolution of the dromaeosaurid tail. PLoS ONE. 7(5), e36790.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 1-206.
Godefroit, Cau, Hu, Escuillie, Wu and Dyke, 2013. A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds. Nature. 498, 359-362.
Godefroit, Demuynck, Dyke, Hu, Escuillie and Claeys, 2013. Reduced plumage and flight ability of a new Jurassic paravian theropod from China. Nature. 498, 359-362.
Brusatte, Lloyd, Wang and Norell, 2014. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Current Biology. 24(20), 2386-2392.
Foth, Tischlinger and Rauhut, 2014. New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers. Nature. 511, 79-82.
Lee, Cau, Naish and Dyke, 2014. Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds. Science. 345(6196), 562-566.
Xu, Zheng, Sullivan, Wang, Xing, Wang, Zhang, O'Connor, Zhang and Pan, 2015. A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings. Nature. 521, 70-73.
Wang, O'Connor, Xu and Zhou, 2019. A new Jurassic scansoriopterygid and the loss of membranous wings in theropod dinosaurs. Nature. 569, 256-259.

Yi Xu, Zheng, Sullivan, Wang, Xing, Wang, Zhang, O'Connor, Zhang and Pan, 2015a
Y. qi Xu, Zheng, Sullivan, Wang, Xing, Wang, Zhang, O'Connor, Zhang and Pan, 2015a
Oxfordian, Late Jurassic
Mutoudeng, Tiaojishan Formation, Hebei, China
Holotype- (STM 31-2) (~700 g) skull (44.5 mm), mandible (43.4 mm), atlas, axis (7.3 mm), third cervical vertebra (7.4 mm), fourth cervical vertebra (7.4 mm), fifth cervical vertebra (7.6 mm), sixth cervical vertebra, seventh cervical vertebra (8.2 mm), eighth cervical vertebra (6.8 mm), ninth cervical vertebra, cervical ribs, several partial dorsal ribs, gastralia, partial scapula (~50 mm), humeri (one partial; 94.8 mm), partial radii, ulnae (one partial; ~88.5 mm), scapholunare, carpal, incomplete styliform elements (~133.5 mm), metacarpal I (9.1 mm), phalanx I-1 (18.3 mm), partial manual ungual I (~15.4 mm), metacarpal II (20.1 mm), phalanges II-1 (one distal; 14.5 mm), incomplete phalanges II-2 (19.7 mm), manual ungual II (15 mm), metacarpals III (one distal; ~21.2 mm), phalanges III-1 (35.2 mm), phalanges III-2 (33.8 mm), phalanges III-3 (23.4 mm), manual unguals III (11.6 mm), manual claw sheaths, fragmentary femora, tibiotarsus (81.7 mm), fibula, fragmentary metatarsi (mt IV 48.9 mm), body feathers, patagia
Diagnosis- (after Xu et al., 2015a) low midline nasal crest; small and posteriorly located external mandibular fenestra; tooth crowns symmetrical in lateral view; tooth crowns considerably wider mesiodistally than their roots; humerus and ulna long relative to tibiotarsus (ratios 1.16 and 1.08 respectively); short humeral deltopectoral crest; long rod-like bone (styliform element) articulating with wrist.
Comments- The holotype was discovered by a farmer and purchased in 2007. Yi is notable for having elongate 'styliform elements' extend from the carpus to support patagia, apparently forming wings in the absence of flight feathers. The document properties of the supplementary information's pdf file include the title "Eomicroraptor 5-12 measurement", suggesting "Eomicroraptor" may have been an earlier name Xu used for Yi.
References- Xu, Zheng, Sullivan, Wang, Xing, Wang, Zhang, O'Connor, Zhang and Pan, 2015a. A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings. Nature. 521, 70-73.
Xu, Zheng, Sullivan, Wang, Xing, Wang, Zhang, O'Connor, Zhang and Pan, 2015b. A bizarre new theropod from the Jurassic of Hebei, China, and the diversification of the Scansoriopterygidae. Journal of Vertebrate Paleontology. Program and Abstracts 2015, 242.

Ambopteryx Wang, O'Connor, Xu and Zhou, 2019
A. longibrachium Wang, O'Connor, Xu and Zhou, 2019
Bathonian-Callovian, Middle Jurassic
Wubaiding, Jiulongshan Formation, Liaoning, China
Holotype- (IVPP V24192) (320 mm, ~300 g, subadult or adult) skull, mandible, eight to ten cervical vertebrae, ten to twelve dorsal vertebrae, dorsal ribs, gastralia, four to fave sacral vertebrae, nine to ten caudal vertebrae, pygostyle (13.49 mm), scapulae (28.50 mm), coracoids, humeri (62.31 mm), radii (51.66 mm), ulnae (54.64 mm), styliform element (54.91 mm), scapholunare, pisiform, metacarpal I (5.57 mm), phalanx I-1 (9.34 mm), metacarpal II (14.99 mm), phalanx II-1 (8.75 mm), phalanx II-2 (11.57 mm), manual ungual II (8.78 mm), metacarpal III (16.99 mm), phalanges III-1 (21.32 mm), phalanges III-2 (16.56 mm), phalanges III-3 (11.93 mm), manual unguals III, ilia (28.36 mm), pubis, ischium, femur (36.82 mm), tibia (53.14 mm), fibula, astragalus, calcaneum, distal tarsal III, distal tarsal IV, phalanx I-1 (4.13 mm), pedal ungual I, metatarsal II, phalanx II-1 (4.98 mm), phalanx II-2 (5.85 mm), pedal ungual II (5.50 mm), metatarsal III (30.97 mm), phalanx III-1 (6.56 mm), phalanx III-2, phalanx III-3 (5.87 mm), pedal ungual III (4.20 mm), metatarsal IV, phalanx IV-1 (5.31 mm), phalanx IV-2, phalanx IV-3 (2.83 mm), phalanx IV-4 (4.99 mm), pedal ungual IV (4.35 mm), body feathers, patagia, ~20 gastroliths (0.71-2.66 mm), ingested bony fragments
Diagnosis- (after Wang et al., 2019) short tail that lacks a transition point and that ends in a fused pygostyle; elongate forelimb 1.3x longer than the hindlimb; proximal margin of humerus more convex, and deltopectoral crest more elongate, than in Yi; ulna substantially wider (2x) than radius; styliform element shorter than humerus; manual phalanx I-1 terminates level with the distal end of metacarpal II; manual phalanx I-1 much shorter than metacarpal II (length ratio is 0.62); manual digit III is proportionally shorter than in Yi; ratio of manual phalanx III-1 to III-2 is greater than in Yi and Scansoriopteryx (1.29); straight, rod-like postacetabular process of ilium; tibia shorter than humerus (also in Yi).
Comments- The holotype was discovered prior to January 2019.  While Wang et al. (2019) only say the Wubaiding locality is a "stratigraphic equivalent of the Haifanggou Formation", Xu et al. (2016) noted "The Callovian Jiulongshan Formation is probably exposed at the Wubaiding Locality." 
Wang et al. (2019) added Ambopteryx to Senter's TWiG analysis and recovered it sister to Yi in Scansoriopterygidae.  When  added to Hartman et al.'s TWiG analysis, it is closer to Epidexipteryx and Scansoriopteryx than Yi.
References- Xu, Zhou, Sullivan, Wang and Ren, 2016. An updated review of the Middle-Late Jurassic Yanliao Biota: Chronology, taphonomy, paleontology and paleoecology. Acta Geologica Sinica. 90(6), 2229-2243.
Wang, O'Connor, Xu and Zhou, 2019. A new Jurassic scansoriopterygid and the loss of membranous wings in theropod dinosaurs. Nature. 569, 256-259.

Epidexipteryx Zhang, Zhou, Xu, Wang and Sullivan, 2008
E. hui Zhang, Zhou, Xu, Wang and Sullivan, 2008
Bathonian-Callovian, Middle Jurassic
Daohugou, Haifanggou Formation, Inner Mongolia, China
Holotype- (IVPP V15471) (164 g; subadult) skull (43 mm), mandibles (39.3 mm), seven cervical vertebrae, cervical ribs, fourteen dorsal vertebrae, twelve dorsal ribs, gastralia, sacrum, sixteen caudal vertebrae, scapulae (31 mm), coracoids (12.2 mm), sternal plates, humeri (50 mm), radii (one proximal; 39.2 mm), ulnae (one proximal; 42 mm), metacarpal I (5.1 mm), metacarpal II (13 mm), phalanx II-1 (7.6 mm), phalanx II-2 (12.4 mm), manual ungual II (10.2 mm), metacarpal III (13.4 mm), phalanx III-2 (14 mm), phalanx III-3 (13.5 mm), manual ungual III (10 mm), ilia (34.2 mm), pubes (27.8 mm), ischia (36.2 mm), femora (51 mm), tibiae (63 mm), fibulae (59 mm), astragalocalcaneum (7 mm wide), distal tarsal III, distal tarsal IV, metatarsal I, incomplete metatarsal II, incomplete metatarsal III (31 mm), incomplete metatarsal IV, feathers
Comments- This specimen was first mentioned by Xu (2000) as a new maniraptoran similar to birds, but also to therizinosaurs, oviraptorosaurs and troodontids. It was later named and described by Zhang et al. (2008), though the manuscript was accidentally leaked September 24th to Nature Precedings, while the final version wasn't published until October 23rd. The extremely short tail compared to Scansoriopteryx may be an ontogenetic feature, as other avialans such as Confuciusornis (= Zhongornis?) and enantiornithines reduce their tail length with age. Thus it may be an older individual of Scansoriopteryx, since it is from the same formation. The metacarpals and manual phalanges were left unidentified in the paper, but are here tentatively assigned positions based on their lengths, as compared to Scansoriopteryx.
References- Xu, 2000. A new feathered maniraptoran dinosaur. The Florida Symposium on Dinosaur Bird Evolution. Publications in Paleontology No.2, Graves Museum of Archaeology and Natural History. p 27.
Zhang, Zhou, Xu, Wang and Sullivan, 2008. A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers. Nature. 455, 1105-1108.

Scansoriopteryx Czerkas and Yuan, 2002
= Epidendrosaurus Zhang, Zhou, Xu and Wang, 2002
S. heilmanni Czerkas and Yuan, 2002
= Epidendrosaurus ningchengensis Zhang, Zhou, Xu and Wang, 2002
Middle Jurassic (?)
Haifanggou/Jiulongshan Formation?, Liaoning?, China
Holotype- (CAGS02-IG-gausa-1/DM 607) (130 mm, ~6 g; juvenile) posterior skull, sclerotic rings, posterior mandibles, hyoids, seven dorsal vertebrae, dorsal rib fragments, gastralia, sacrum, twenty-two caudal vertebrae, fourteen chevrons, distal scapula, coracoid, partial furcula, humerus (18.5 mm), radii (one distal; 14.75 mm), ulnae (one distal; 15 mm), distal carpals I, metacarpals I (2.1 mm), phalanges I-1 (5 mm), manual unguals I (3 mm), metacarpals II (5.5 mm), phalanges II-1 (3.1 mm), phalanges II-2 (5.2 mm), manual unguals II (3 mm), metacarpals III (5.75 mm), phalanges III-1 (7.1 mm), phalanges III-2 (6.5 mm), phalanges III-3 (6 mm), manual ungual III (2.8 mm), ilia (11.5 mm), distal pubes (9 mm), ischia (11.5 mm), femora (16.5 mm), tibiae (one distal; 19.25 mm), (?)fibulae (one distal), astragali, calcaneum, distal tarsal III, distal tarsal IV, metatarsal I, phalanx I-1 (2.75 mm), pedal ungual I (1.9 mm), metatarsals II (11.9 mm), phalanx II-1 (2.75 mm), phalanx II-2 (2.8 mm), pedal ungual II (2.5 mm), metatarsals III (12 mm), phalanx III-1 (2.5 mm), phalanx III-2 (2 mm), phalanx III-3 (2.5 mm), pedal ungual III (2 mm), metatarsals IV (1.5 mm), phalanx IV-1 (2 mm), phalanx IV-2 (1.25 mm), phalanx IV-3 (1.1 mm), phalanx IV-4 (2 mm), pedal ungual IV (2 mm), metatarsal V, feathers, scales
Bathonian-Callovian, Middle Jurassic
Daohugou, Haifanggou Formation, Inner Mongolia, China
Referred- (IVPP V12653; holotype of Epidendrosaurus ningchengensis) (130 mm, ~6 g; juvenile) frontals (7.8 mm), parietals (5.3 mm), sclerotic ring, mandibles (18 mm), nine cervical vertebrae, cervical rib, four dorsal vertebrae, five dorsal ribs, ten caudal vertebrae, caudal impression, several chevrons, scapulae (11.3 mm), coracoid, humeri (17.1 mm), radius (15 mm), ulna (15 mm), distal phalanx I-1, manual ungual I (4.1 mm), metacarpal II (5.2 mm), phalanx II-1 (3.2 mm), phalanx II-2 (5.4 mm), manual ungual II (3.2 mm), metacarpal III (5.8 mm), phalanges III-1 (7.3 mm), phalanges III-2 (6.8 mm), phalanges III-3 (6.3 mm), manual ungual III (2.9 mm), femora (one distal; 16.2 mm), tibiae (18.9 mm), fibulae, astragalus, metatarsals I, phalanges I-1, pedal unguals I, metatarsals II, phalanges II-1, phalanges II-2, pedal ungual II, metatarsals III (11.9 mm), phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, metatarsals IV, phalanges IV-1, phalanges IV-2, phalanx IV-3, phalanges IV-4, pedal unguals IV, feathers (Zhang , Zhou, Xu and Wang, 2002)
Comments- Scansoriopteryx and Epidendrosaurus appear to be synonymous, but there are complications in deciding which name has priority. The description Epidendrosaurus was submitted June 10th, 2002, published online on August 21st, but not published in print until September 30th. The description of Scansoriopteryx is dated August 1st, 2002, but was not distributed until around September 2nd. Indeed, Zhang (DML, 2002) stated he received faxed copies of the paper from Czerkas on August 26th-29th which still lacked page numbers. Zhang (DML, 2002) also cited a Naturwissenschaften editor as claiming that nomenclatural acts published in Springer Verlag journals (including Naturwissenschaften) are valid at the date of their online publication as long as a print version follows. Harris (2004) has formally recommended such an amendment to articles 8.1.3 and 9.8 of the ICZN, but this has not been adopted by the ICZN as of this time. Thus online publication dates do not count even if followed by a print version, regardless of the presence of a Digital Object Identifier (DOI) code to ensure citability. This makes Scansoriopteryx the valid name, as it was published in print almost a month prior to Epidendrosaurus. Yet if Harris' suggestions are incorporated into the ICZN, they may be retroactive and thus favor Epidendrosaurus, as the online version of its description was distributed prior to the time it can be proven Scansoriopteryx's description was.
Czerkas and Yuan (2002) stated Scansoriopteryx's holotype derived from "the Dawangzhangzi fossil site of Lingyaun[sic] City", but Wang et al. (2005) suggested it "probably came from the same horizon [as Epidendrosaurus] in Daohugou Village, contrary to the originally reported middle Yixian Formation at the Dawangzhangzi locality" without evidence. Czerkas has apparently revised his opinion since 2004 at least and now believes the latter as well.  There are sites close to Lingyuan that expose Haifanggou/Jiulongshan beds such as Guancaishan, Wubaiding and Fangshen, so that  intermediate alternatives exist.  While Zhang (DML, 2002) implied it had been smuggled into the US, Ford (DML, 2002) stated personal communication with Czerkas revealed that he has been loaned the specimen from a Chinese Museum (presumably CAGS) through a middleman. Regardless, it does seem there is little original stratigraphic information on the specimen, and it is here referred to the Haifanggou/Jiulongshan Formation only tentatively.
Czerkas and Yuan's description of Scansoriopteryx is fraught with errors symptomatic of those who place maniraptorans outside Theropoda. They believe theropods are defined by being terrestrial and having a third manual digit shorter than the second digit, though dinosaur workers near universally define it phylogenetically instead (generally as those taxa closer to birds than to sauropods, though more recently using Allosaurus as the internal specifier instead of a bird). The authors also confusingly classify Scansoriopteryx as a maniraptoran and a saurischian, but exclude it from Theropoda and more tentatively, Dinosauria. This is not possible given the phylogenetic definitions of these clades, as theropods must be saurischians (Saurischia is defined as including a theropod) and saurischians must be dinosaurs (Dinosauria is defined as including a saurischian). The exact phylogeny Czerkas advocates is uncertain, since he never states explicitly where sauropodomorphs or ornithischians go, though he seems to have these groups and theropods branching off (para- or monophyletically?) before Scansoriopteryx, which is itself outside a clade containing deinonychosaurs, oviraptorosaurs and birds. Czerkas and Yuan state there are "massive reversals secondarily resembling primitive characteristics" that would have to take place if Scansoriopteryx were a theropod. The few that are listed are either also present in some other maniraptoriforms (broad sacral vertebrae; metacarpal III longer than II; manual phalanx III-3 shorter than III-1 and III-2; partially closed acetabulum; narrow pubic peduncle on ilium), or misinterpreted (unfused clavicles; robust fibula), except for the short pubis. Notably the ischium also differs from most theropods in lacking an obturator notch, though this is not commented on by the authors. In any case, Czerkas' phylogeny has received no support from phylogenetic analysis, and Scansoriopteryx has been universally recovered as a paravian theropod, generally a basal avialan.
References- Czerkas, 2000. An arboreal theropod. The Florida Symposium on Dinosaur Bird Evolution. Publications in Paleontology No.2, Graves Museum of Archaeology and Natural History. p 14.
Czerkas and Yuan, 2002. An arboreal maniraptoran from Northeast China. Feathered Dinosaurs and the Origin of Flight. The Dinosaur Museum Journal. 1, 63-95.
Ford, DML 2002. https://web.archive.org/web/20190416181247/http://dml.cmnh.org/2002Sep/msg00704.html
Zhang, DML 2002. https://web.archive.org/web/20190416181245/http://dml.cmnh.org/2002Sep/msg00673.html
Zhang , Zhou, Xu and Wang, 2002. A juvenile coelurosaurian theropod from China indicates arboreal habits. Naturwissenschaften. 89, 394-398.
Harris, 2004. Published works" in the Electronic Age: Recommended amendments to Articles 8 and 9 of the Code. Bulletin of Zoological Nomenclature. 61(3), 138-148.
Marjanovic, DML 2004. https://web.archive.org/web/20190416181247/http://dml.cmnh.org/2004Apr/msg00048.html
Wang, Zhou, He, Jin, Wang, Zhang, Wang, Xu and Zhang, 2005. Stratigraphy and age of the Daohugou Bed in Ningcheng, Inner Mongolia. Chinese Science Bulletin. 50(20), 2369-2376.
Czerkas and Feduccia, 2014. Jurassic archosaur is a non-dinosaurian bird. Journal of Ornithology. 155(4), 841-851.

Avialae sensu Gauthier and de Queiroz, 2001
Definition- (feathered wings homologous with Vultur gryphus and used for powered flight)

unnamed clade (Shenzhouraptor sinensis + Passer domesticus)
Diagnosis- nasal process of premaxilla over 50% of snout length (also in oviraptoriforms and Epidexipteryx); dorsal centra much longer than wide (also in many non-paravians and Anchiornis; absent in Jixiangornis, Sapeornis, Alethoalaornis, Eoalulavis, Archaeorhynchus and Patagopteryx); scapula tapers distally (also in Deinocheirus, Nothronychus and Bambiraptor; absent in Confuciusornithidae, Songlingornis(?) and Hesperornis); scapula and coracoid articulate at <90 degree angle (absent in Hesperornithes and Ratites); strut-like coracoid (absent in Confuciusornis zhengi and Hesperornithes); acrocoracoid process (absent in Jixiangornis and Hesperornis); forelimb (humerus + ulna) over 110% of hindlimb (femur + tibiotarsus) (also in Rahonavis; absent in Yandangornis, Dalianraptor, Confuciusornithidae, many enantiornithines and many euornithines more derived than Archaeorhynchus); ulna over 97% length of humerus (absent in Jixiangornis, Dalianraptor, Confuciusornithidae, Elsornis, Patagopterygiformes and basal Carinatae); semilunate carpal fused to metacarpals II and III (also in Anchiornis; not in Jixiangornis); semilunate carpal covers less than half of proximal edge of metacarpal I (also in Anchiornis; absent in Jixiangornis, Dalianraptor and Zhongjianornis); manual phalanx II-1 with posterior flange (also in Microraptoria; absent in "Cathayornis" chabuensis); opisthopubic pelvis (also in Parvicursorinae, some troodontids and Microraptoria + Eudromaeosauria); antitrochanter located posterodorsal to acetabulum (absent in Patagopteryx and Yixianornis); trochanteric crest on femur (also in Parvicursorinae, derived troodontids and Rahonavis); ectocondylar tuber forms single articular surface with lateral condyle of femur (also in Deinonychus and Anchiornis; absent in Zhongornis, Shanweiniao and Alamitornis- ontogenetic?); laterally projected fibular trochlea on femur (also in Alvarezsauridae, Protarchaeopteryx, Rahonavis and Unenlagia); distal tarsals fused to metatarsus (also in Patagonykus, Microraptor and Velociraptor).

Dalianraptor Gao and Liu, 2005
D. cuhe Gao and Liu, 2005
Early Albian, Early Cretaceous
Jiufotang Formation, Liaoning, China
Holotype- (D2139) (multiple taxa?) (625 mm) skull, mandible, cervical vertebrae (series 82 mm), dorsal vertebrae, eight dorsal ribs, ~16-18 caudal vertebrae (series ~310 mm), incomplete scapula (30 mm), incomplete furcula, sternum, humeri (52 mm), radius (42 mm), ulnae (46 mm), semilunate carpal, metacarpals I (6 mm), phalanges I-1 (20, 21 mm), manual unguals I (20, 17 mm), metacarpals II (23 mm), phalanges II-1 (22 mm), phalanges II-2 (19, 22 mm), metacarpals III (22 mm), phalanges III-1 (5 mm), phalanges III-2 (12 mm), phalanges III-3 (13 mm), manual unguals III (17, 16 mm), partial ilium (32 mm), incomplete femora (49 mm), tibiae (68, 63), fibula (36 mm), phalanges I-1 (9 mm), pedal unguals I (12 mm), metatarsals II (24 mm), phalanges II-1 (7 mm), phalanges II-2 (7 mm), metatarsals III (43 mm), phalanges III-1 (14 mm), phalanges III-2 (11 mm), phalanges III-3 (13, 11 mm), metatarsals IV (43 mm), phalanges IV-1 (6 mm), phalanges IV-2 (8 mm), phalanges IV-3 (6 mm), phalanges IV-4 (5 mm), pedal unguals IV (10 mm), retrices
Diagnosis- (after Gao and Liu, 2005) small; mandible ends posterior to snout tip; anterior dentary has ventral crest; less than twenty caudal vertebrae; forelimb/hindlimb ratio 0.82; developed deltopectoral crest; metacarpus not fused; gracile hindlimb; pedal digit I reversed.
Comments- This specimen has a skull and tail similar to Shenzhouraptor, a forelimb similar to confuciusornithids and possibly enantiornithine pedes. O'Connor et al. (2012) state it has been tampered with, leading O'Connor and Zhou (2013) to exclude it from their analysis. It is here considered a probable chimaera, pending further study.
References- Gao and Liu, 2005. A new avian taxon from Lower Cretaceous Jiufotang Formation of western Liaoning. Global Geology. 24(4), 313-316. (in Chinese).
O'Connor, Sun, Xu, Wang and Zhou, 2012. A new species of Jeholornis with complete caudal integument. Historical Biology. 24(1), 29-41.
O'Connor and Zhou, 2013. A redescription of Chaoyangia beishanensis (Aves) and a comprehensive phylogeny of Mesozoic birds. Journal of Systematic Palaeontology. 11(7), 889-906.

Neimengornis Wang, Wang, Guo, Kang, Ma and Ju, 2021
N. rectusmim Wang, Wang, Guo, Kang, Ma and Ju, 2021
Early Albian, Early Cretaceous
Jiufotang Formation, Liaoning, China
Holotype- (IMMNH-PV00122) skull (67 mm), mandibles, atlas, axis, about seven postaxial cervical vertebrae, last seven dorsal vertebrae (~9-10 mm), dorsal ribs, gastralia, synsacrum (36.8 mm), about thirty caudal vertebrae, proximal chevrons, scapula (55.8 mm), scapulocoracoid, furcula, posterolateral sternal process, humeri (89, ~80 mm), radii (85, ~81 mm), ulnae (88, ~80 mm), scapholunares, pisiforms, semilunate carpals, metacarpals I (7.4, ~6.2 mm), phalanges I-1 (27.7 mm), manual unguals I (one partial; 17.9 mm), metacarpals II (38.6, ~34 mm), phalanges II-1 (17.9 mm), phalanges II-2 (22.8 mm), manual unguals II (10.9 mm), metacarpals III (34, ~37 mm), phalanges III-1 (20 mm), phalanx III-2 (4.5 mm), phalanx III-3 (25 mm), manual ungual III (15.8 mm), manual phalanx III-? (~12 mm), ilia (53.5, ~45 mm), pubes (77.3 mm), partial ?ischium, femora (74, ~67 mm), tibia (~84 mm), tibiotarsus (90 mm), astragalaocalcaneum, metatarsals I, phalanges I-1 (13.2 mm), pedal unguals I (19.6 mm), tarsometatarsi (43.6 mm; II- 42.5, III- 43.6, IV- 41.7 mm), phalanges II-1 (10.5 mm), phalanges II-2 (12.1 mm), pedal unguals II (14.8 mm), phalanges III-1 (12.2 mm), phalanges III-2 (11.3 mm), phalanges III-3 (11.7 mm), pedal unguals III (13.2 mm), phalanges IV-1 (9.4 mm), phalanges IV-2 (7 mm), phalanges IV-3 (8.2 mm), phalanges IV-4 (9 mm), pedal unguals IV (14.8 mm), metatarsal V?, pedal claw sheaths, remiges, retrices
Other diagnoses- Wang et al. (2021) listed several supposedly diagnostic characters- undeveloped mid and distal caudal zygapophyses and chevrons; shorter forelimbs than other jeholornithiforms (forelimb/hindlimb ratio 1.09 vs 1.2-1.35); shorter deltopectoral crest (27% of humeral length); straight metacarpal III; pedal digit I largest in pes.  The zygapophyses seem to be developed similarly to Shenzhouraptor, while the missing chevrons are near certainly due to preparation.  The other differences are near certainly due to the specimen being a chimaera of different individuals/taxa (see below).
Comments- Discovered during construction of the Inner Mongolia Museum of Natural History which concluded in 2008, IMMNH-PV00122 was described by Wang et al. (2021) as a new genus of jeholornithiform.  The supposed hyoid is more probably a jugal based on its posterior expansion, while the labeled nasal is more likely a postorbital and the dorsal area labeled maxilla probably made of frontal and nasal.  There is a triangular element on top of the left humerus which is not mentioned in the text, but matches the posterolateral sternal processes of ornithothoracines.  More importantly, this specimen appears to be a chimaera assembled from different individuals.  The right humerus, radius and ulna are 11%, 5% and 10% longer respectively than the left; right metacarpals I and II are 20% and 15% longer while III is 8% shorter than the left; on the right manus digit II with a larger distal articulation is given a small ungual while digit III has a large ungual matched with its more slender phalanx; there is a slender phalanx in the left manus that doesn't match any of the phalanges in the right manus; the left ilium is 84% the size of the right one with a blunter postacetabular process and less projected ischial peduncle; the right femur is 10% longer than the left, the right tarsometatarsus 13% longer, and pedal phalanges are mostly different in length between pedes.  Other probable indications are the differently shaped scapulae; arrangement of carpals in the left manus with the two small ones positioned alongside metacarpal I at the bases of metacarpals II and III; left distal astragalocalcaneum smaller than the right and seemingly disarticulated from the tibia; and retrices appearing as featureless narrow dark lines extending halfway down the tail.  With that in mind, the element identification listed above is based on Wang et al.'s interpretation of the skeleton as articulated, so the phalanges in particular are likely placed incorrectly and the left ?ulna could be a radius or tibiotarsus.  The right scapula, humeri (e.g. the short deltopectoral crest of the diagnosis) and ilia seem more similar to Sapeornis, although the skull, tail and furcula are Shenzhouraptor-grade, while the sacrum has an expanded but distally unfused last rib as in Confuciusornis and the right scapulocoracoid is more like confuciusornithiforms in the apparent fusion and short coracoid.  The radii, left ulna, tarsometatarsi and pubes all seem to be avialan, although the latter plausibly had their distal end modified to be shorter and pointed.  The right pes may be Sapeornis, which also has pedal ungual I largest and is similar in proportions.  Although the robust and straight metacarpal III and small ungual II might suggest the right manus is from a confuciusornithiform, phalanx I-1 doesn't extend past metacarpal II, digit II is much smaller and phalanx III-2 is the tiny one (unlike confuciusornithiforms and the manus in Dalianraptor where III-1 is), pointing to it being an artificial articulation of elements.  Thus we have a situation much like Dalianraptor, and Neimengornis is likewise placed by Shenzhouraptor as all components seem to be at least as close to Aves as it is.
Reference- Wang, Wang, Guo, Kang, Ma and Ju, 2021. A new jeholornithiform identified from the Early Cretaceous Jiufotang Formation in western Liaoning. Geological Bulletin of China. 40(9), 1419-1427.

"Zhyraornis" Nessov and Borkin, 1983
"Z. kashkarovi" Nessov and Borkin, 1983
Mid-Late Turonian, Late Cretaceous
Bissekty Formation, Uzbekistan
Material- (TsNIGRI 43/11915) dorsal vertebra (6.9 mm)
Comments- This dorsal was originally included in a figure in Nessov and Borkin (1983), labeled as Zhyraornis kashkarovi. Yet that species was later described by Nessov (1984) based on a synsacrum (TsNIGRI 42/11915), with the dorsal vertebra as a paratype. As the name was not associated with a description in 1983, it is a nomen nudum and since it referred to a different specimen than what became Z. kashkarovi, it is given its own entry here. Nessov (1992) later regarded it as an indeterminate bird, while Kurochkin (1996) merely noted it was similar in size to Zhyraornis kashkarovi.
The dorsal is from an avialan due to its large lateral central fossae, possibly an ornithothoracine based on its age. It is probably not an enantiornithine as the parapophyses are anteriorly placed, so may actually belong to Zhyraornis. It can also be excluded from Hesperornithes and Aves due to its amphicoely. It is here placed as Avialae incertae sedis.
References- Nessov and Borkin, 1983. New records of bird bones from the Cretaceous of Mongolia and Soviet Middle Asia. USSR Academy of Sciences, Proceedings of the Zoological Institute. 116, 108-110 (in Russian).
Nessov, 1984. [Upper Cretaceous pterosaurs and birds from Central Asia] Paleontologicheskii Zhurnal. 1, 47-57.
Nessov, 1992. Review of localities and remains of Mesozoic and Paleogene birds of the USSR and the description of new findings. Russkii Ornitologicheskii Zhurnal. 1(1), 7-50.
Kurochkin, 1996. A new enantiornithid of the Mongolian Late Cretaceous, and a general appraisal of the Infraclass Enantiornithes (Aves). Russian Academy of Sciences, special issue. 50 pp.

undescribed avialan (Sanz, Chiappe, Fernadez-Jalvo, Ortega, Sanchez-Chillon, Poyato-Ariza and Perez-Moreno, 2001)
Late Barremian, Early Cretaceous
Calizas de La Huerguina Formation, Spain
Material- (LH 11386 bird 4) (juvenile) femur, tibia, metatarsal I, phalanx I-1, pedal ungual I, metatarsus, phalanx III-3, phalanx IV-3
Comments- This specimen is one of the two most fragmentary of four juvenile birds found associated in a theropod or pterosaur pellet. It was only identified as a bird by Sanz et al. (2001), and is the specimen on the left which is colored black in their illustration. The curved metatarsal I and elongate digit I are similar to derived avialans, but its relationships cannot be determined further without better description or illustration.
Reference- Sanz, Chiappe, Fernadez-Jalvo, Ortega, Sanchez-Chillon, Poyato-Ariza and Perez-Moreno, 2001. An Early Cretaceous pellet. Nature. 409, 998-999.

Jeholornithiformes Zhou and Zhang, 2006
Jeholornithidae Zhou and Zhang, 2006
Diagnosis- (Jeholornis prima + Jeholornis palmapenis + Jeholornis curvipes) (Lefevre et al., 2014)
Comments- Zhou and Zhang erected both of these taxa to include only Shenzhouraptor (which they viewed as a synonym of Jeholornis, in addition to Jixiangornis). If Jixiangornis, Dalianraptor or another taxon is found to be more closely related to Shenzhouraptor than to Aves, then they may become useful. Lefevre et al. (2014) provided a definition that ironically assures this family to be identical to or within Jeholornis unless a species is misidentified. As I believe curvipes to be Jixiangornis, the family could be far more inclusive if that genus is closer to Aves than Shenzhouraptor. Thus the definition is flawed and should be stem-based in relation to Jeholornis prima.
Reference- Zhou and Zhang, 2006. Mesozoic birds of China- A synoptic review. Vertebrata PalAsiatica. 44(1), 74-98.
Lefevre, Hu, Escuillie, Dyke and Godefroit, 2014. A new long-tailed basal bird from the Lower Cretaceous of North-eastern China. Biological Journal of the Linnean Society. 113, 790-804.
Shenzhouraptor Ji, Ji, You, Zhang, Yuan, Ji, Li and Li, 2002
= Jeholornis Zhou and Zhang, 2002
S. sinensis Ji, Ji, You, Zhang, Yuan, Ji, Li and Li, 2002
= Jeholornis prima Zhou and Zhang, 2002
= Jeholornis "palmapenis" O'Connor, Sun, Xu, Wang and Zhou, online 2011
= Jeholornis palmapenis O'Connor, Sun, Xu, Wang and Zhou, 2012
Early Albian, Early Cretaceous
Jiufotang Formation, Liaoning, China
Holotype- (LPM 0193) (subadult) partial skull, incomplete mandible, five or six cervical vertebrae, ten to twelve dorsal vertebrae, dorsal ribs, uncinate processes, three sacral vertebrae, (caudal series ~320 mm) twenty-three to twenty-five caudal vertebrae, chevrons, scapulae (one incomplete; ~48 mm), partial coracoid, furcula, partial sternal plate, humeri (79.8 mm), radius, ulnae (83.4 mm), scapholunare, pisiform, semilunate carpal, metacarpal I (~7.7 mm), phalanx I-1 (~22.3 mm), manual ungual I, metacarpal II (36.7 mm), phalanx II-1 (17.8 mm), phalanx II-2 (19.2 mm), manual ungual II (13.9 mm on curve), metacarpal III (36.6 mm), phalanx III-1 (~8 mm), phalanx III-2 (~4.3 mm), phalanx III-3 (~9 mm), manual ungual III, ilia (one fragmentary; ~40.8 mm), pubes (one partial; ~56.4 mm), incomplete ischium, femora (55.4 mm), tibiae (68.3 mm), metatarsal I (7.8 mm), phalanx I-1 (9 mm), pedal ungual I (12.1 mm on curve), metatarsals II (29.8 mm), phalanx II-1 (9 mm), phalanx II-2 (10.5 mm), pedal ungual II, metatarsals III (34.6 mm), phalanx III-1 (10.9 mm), phalanx III-2 (10.6 mm), phalanx III-3 (7.3 mm), pedal ungual III, metatarsals IV (31.8 mm), phalanx IV-1 (8.2 mm), phalanx IV-2 (6.7 mm), phalanx IV-3 (6.2 mm), phalanx IV-4, pedal ungual IV, remiges (to 210 mm), retrices
Referred- (IVPP V13274; holotype of Jeholornis prima) (one year old) (1.5 kg) skull, mandibles, hyoids, five cervical vertebrae, seven dorsal vertebrae, dorsal ribs, gastralia, sixth sacral vertebra, twenty-two caudal vertebrae, twenty chevrons, incomplete scapula, coracoids (39 mm), partial furcula, partial sternal plate, posterolateral sternal process, humeri (110 mm), radii (~102 mm), ulnae (109 mm), pisiform, metacarpals I (~13 mm), phalanx I-1 (~30 mm), manual unguals I, carpometacarpus (one incomplete; 47 mm), phalanges II-1 (~23 mm), phalanges II-2 (~24 mm), manual unguals II, phalanx III-1, phalanx III-2, phalanges III-3, manual unguals III, ilium, pubes (73.6 mm), incomplete ischium, femora (one partial; 78.3 mm), tibiae (93 mm), partial fibula, astragali, calcaneum, pedal ungual I, proximal metatarsus (~47 mm), phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, eight pedal phalanges, five pedal unguals, metatarsal V, stomach contents (Zhou and Zhang, 2002)
(IVPP V13550) (subadult) skull, mandible, about ten cervical vertebrae, about thirteen dorsal vertebrae, partial dorsal ribs, sixth sacral vertebra, twenty-seven caudal vertebrae (~299 mm), chevrons, ilia, pubis, ischium, femora (55.6 mm), tibiae (67 mm), metatarsal I, phalanges I-1, pedal unguals I, metatarsals II, phalanges II-1, phalanges II-2, pedal unguals II, metatarsals III (36.5 mm), phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, metatarsals IV, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, retrices (Zhou and Zhang, 2003)
(IVPP V13553) (980 g; subadult) (less than one year old) (285 g) skull, cervical vertebrae, dorsal vertebrae, dorsal ribs, sacrum, twenty-four caudal vertebrae (~387 mm), scapulae, partial coracoid (~37 mm), furcula, humeri (94 mm), radii (~91 mm), ulnae (96 mm), metacarpal II (45 mm), phalanx II-1, phalanx II-2, metacarpal III, phalanx III, ilia, pubes (51.8 mm), femora (64 mm), tibiae (76 mm), distal tarsal, metatarsal I, phalanx I-1, pedal ungual I, metatarsals II, phalanges II-1, phalanges II-2, pedal unguals II, metatarsals III (37 mm), phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, metatarsals IV, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, remiges (Zhou and Zhang, 2003)
(IVPP V13886) specimen including dorsal vertebrae, scapulae, incomplete coracoids, incomplete sternum and humerus (Wu, Bailleul, Li, O'Connor and Zhou, 2021)
(SDM 20090109; holotype of Jeholornis palmapenis) incomplete skull, partial mandibles, nine or ten cervical vertebrae, cervical ribs, twelve dorsal vertebrae, three dorsal ribs, gastralia, synsacrum, twenty-seven caudal vertebrae, chevrons, partial ilia, pubes (49 mm), ischia, femora (57.9 mm), tibiae (76.2 mm), fibula, astragalus, distal tarsal III, distal tarsal IV, tarsal, metatarsals I, phalanges I-1, pedal unguals I, metatarsals II, phalanx II-1, phalanges II-2, pedal unguals II, metatarsals III (40.1 mm), phalanges III-1, phalanx III-2, phalanx III-3, pedal unguals III, metatarsals IV, phalanges IV-1, phalanx IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, metatarsal V, pedal claw sheaths, four to five remiges, eleven retrices (60-90 mm) (O'Connor et al., 2012)
(STM 3-8) skull, sclerotic plates, mandibles, few postcranial elements including caudal vertebrae and ilium (Zheng et al., 2014)
specimen including furcula, forelimbs, hindlimbs including pedal digit I and remiges (Yuan and Ji, 2004)
Diagnosis- (modified after Zhou and Zhang, 2002) lacrimal with two vertical and elongated pneumatic fossae; dentary symphysis fused (also in Confuciusornithidae, Gobipteryx, Apsaravis and Aves; possibly ontogenetically absent in known Jixiangornis); manual phalanx III-2 <60% of the length of III-1 (also in some dromaeosaurids and Jixiangornis); manual phalanges III-1 and III-2 articulate to be medially concave (also in Jixiangornis).
(after Zhou and Zhang, 2006) premaxilla toothless (also in Jixiangornis, Yandangornis, Zhongjianornis, Confuciusornithidae and Aves).
(after O'Connor er atl., 2012) two pairs of pleurocoels in anterior dorsal vertebrae (unknown in Jixiangornis).
(proposed) jugal dorsal process angled anteriorly; chevrons contact at distal tips (also in Jixiangornis); scapula and coracoid with mobile articulation (also in Rahonavis, Jixiangornis and Ornithothoraces); coracoid with concave articulation with scapula (also in Jixiangornis and Euornithes).
Other diagnoses- Ji et al. (2002) included several characters in their diagnosis. Jixiangornis has a comparable number of caudal vertebrae, and almost all deinonychosaurs and basal avialans have distal caudal centra 3-4 times longer than tall. Robust, well developed forelimbs and a broad manual phalanx II-1 could be said to be present in most avialans. The deltopectoral crest is identical in length in Jixiangornis. The forelimb (humerus+ulna+metacarpus) to hindlimb (femur+tibia+metatarsus) ratio is over 1.3 in IVPP V13553 and nearly identical to Jixiangornis. The remiges exceed ulnar+manual length in confuciusornithids and enantiornithines (e.g. Eoenantiornis) as well, so is probably a derived avialan character.
Zhou and Zhang (2002) included additional characters in their diagnosis. Robust mandibles are also present in Jixiangornis, Dalianraptor and confuciusornithids. The number of caudal vertebrae behind the transition point varies between twenty and twenty-two (Zhou and Zhang, 2003), which is comparable to some other basal paravians like Scansoriopteryx, Microraptor and Sinusonasus. The fenestra in the distal end of the posterolateral sternal process turned out to be in sternal rib four (Zheng et al., 2020).
Ji et al. (2003) added a couple problematic characters. Teeth are not absent, but are present in the maxilla and dentary. The U-shaped furcula is shared with other basal paravians.
Of O'Connor et al.'s (2012) characters, the teeth being small, blunt and conical looks comparable to Sapeornis. The slightly opisthopubic pelvis is intermediate between Archaeopteryx and Sapeornis, so is not an autapomorphy. Similarly, a posteromedially oriented hallux is intermediate between Archaeopteryx and Confuciusornis. Anteriorly-limited dentary teeth are intermediate between extensive dentary teeth in Archaeopteryx and the toothless dentary of other non-ornithothoracine birds (Sapeornis, Zhongjianornis, confuciusornithids, Yandangornis) and may be basal for ornithothoracines.
Comments- Wang et al. (2014) proposed to emmend Jeholornis prima to Jeholornis primus following ICZN Article 31.2. However, gender disagreement is not listed under Article 32.5 as a property which must be corrected, leaving prima as the correct original spelling (ICZN Article 32.2). Note the description of palmapenis was released in November 2011 but not officially published until January 2012.
While Zhou and Zhang (2002) claimed the tail has "unexpected elongated prezygopophyses and chevrons, resembling that of dromaeosaurids", they are actually far shorter than most dromaeosaurids and resemble generalized paravians such as Scansoriopteryx, troodontids and Mahakala instead.
Jeholornis- Both Shenzhouraptor and Jeholornis were named in July 2002, with Shenzhouraptor appearing in the July issue of Geological Bulletin of China, and Jeholornis appearing in the July 25th issue of Nature. I first recognized them as synonymous on the DML, which has been the consensus in the literature as well. Ji et al. (2003) made Jeholornis a junior synonym of Shenzhouraptor without comment, incorrectly making the Jeholornis holotype a paratype of Shenzhouraptor. Zhou and Zhang (2006) on the other hand, made Shenzhouraptor a junior synonym of Jeholornis, again without discussion. They stated the ICZN gives priority to a weekly journal instead of a monthly journal, undoubtedly based on Article 21.3.1. Yet, that article only applies in the absence of evidence of "the earliest day on which the work is demonstrated to be in existence as a published work." As Olshevsky (DML, 2002) noted, Wang (2002) reported the Shenzhouraptor article "were published in this month's issue of the Geological Bulletin of China" as of July 23rd, two days before Jeholornis was published. Thus Shenzhouraptor has precedence if the genera are synonymous. Somewhat oddly, no one has yet published a detailed rationale for their synonymy, though Li et al. (2010) did state both have long tails of more than 20 vertebrae (symplesiomorphic), similar forelimb/hindlimb ratios and well developed deltopectoral crests (also in Sapeornis and confuciusornithids).
Comparison is hindered by the short description of each taxon and low resolution photos for much of Jeholornis. Shenzhouraptor's holotype was reported to have no observed teeth, yet the Jeholornis holotype has three tiny dentary teeth, IVPP V13550 has two, and the palmapenis type has two maxillary teeth. I agree with Chiappe and Dyke (2006) that poor preservation in Shenzhouraptor may be to blame, as they are hard to discern even in the published photo of Jeholornis. Ji et al. report that Shenzhouraptor has a straight mandible, but the lower edge is difficult to determine given published photos. The caudal vertebral count of Shenzhouraptor was reported as 23-25, which is within the range of individual variation of the Jeholornis holotype (22), IVPP V13553 (24) and V13550 (27).  There seems to be a deeper dorsal concavity just posterior to the acromion in Shenzhouraptor than the referred Jeholornis specimen IVPP V13553, but this is poorly preserved in the Jeholornis holotype. The first metacarpal and phalanx I-1 in Shenzhouraptor have an "unclear" suture, while that in the Jeholornis holotype is obvious. Whether Shenzhouraptor's condition is anatomical or taphonomic is uncertain. Phalanx II-2 is 108% of II-1 in Shenzhouraptor, but 92% in IVPP V13553 and ~96% in Jeholornis. Yet this is known to vary by 28% in Deinonychus and over 80% in Struthiomimus and Dromiceiomimus. The third manual digit would seem to differ in the ratio between phalanges III-2 and III-1 based on the illustration of Shenzhouraptor, which has a ratio of ~80% compared to Jeholornis' reported ratio of <50%. Yet the photo of Shenzhouraptor's manus suggests an alternative identification where the supposed proximal end of III-2 is really the distal end of III-1, based on apparent distal condyles and phalanx outlines. Indeed, Ji et al. only dotted in the boundary in their illustration, and the resulting ratio of ~50% matches the ~40% ratio measured in Jeholornis. The manus is otherwise extremely similar in the two holotypes, except that in Jeholornis metacarpal III reaches slightly past metacarpal II. The ilia seem to differ in that Shenzhouraptor's has a large ventral process on the preacetabular process while Jeholornis' tapers based on the illustration. Yet IVPP V13553 has an ilium in medial view which seems to taper as well, unless the ventral process is taken into account, which is separated from the main blade by the cuppedicus fossa. In the Jeholornis holotype, the photo indicates that the ilium is overlain by the caudal series, so is probably in medial view as well. The ventral process would be underneath the second and third caudals and chevrons if it exists, so this difference cannot be substantiated. IVPP V13553 differs from both holotypes in having a postacetabular process which is blunt posteriorly. The proximodorsal ischial process in Jeholornis' holotype is expanded distally, while Shenzhouraptor's is rounded. Perhaps more importantly, the ischium of Jeholornis is illustrated with a pronounced dorsal kink about halfway down the shaft, inviting comparisons to the mid dorsal processes of some other maniraptorans. Shenzhouraptor's is gently concave. Examination of the photo indicates that the ischium in Jeholornis is straight until a crack in the slab interrupts it, after which what must have been identified as the distal ischium extends at a more ventral angle. Yet this supposed distal ischium is just as parsimoniously a fibular fragment, while the true distal ischium could be underneath the left tibiotarsus or right femur. The proximal metatarsus of Shenzhouraptor is unfused, unlike the Jeholornis holotype, but this could be ontogenetic due to its smaller size. Similarly, the small IVPP V13553 has a free distal tarsal and seems to have an unfused metatarsus. Shenzhouraptor was reported to have an unreversed hallux, while Jeholornis' was said to be reversed. Yet in Jeholornis the distal metatarsus is almost completely destroyed by a gap in the matrix, all phalanges except for right digit IV are disarticulated, and the probable hallucial ungual (based on its proximal position) is oriented to curve in the same direction as five of the six other pedal unguals in any case. IVPP V13550 has a hallux preserved in unreversed position like the Shenzhouraptor holotype, while Li and Zhang (2008) find the preserved orientation depends on taphonomy. Wang et al. (2020) list unfused metacarpals II and II as different in Shenzhouraptor, as Jeholornis' was reported as "fused at the proximal end" by Zhou and Zhang, but its outline is visible even proximally, so that such incipient fusion might be missed or ontogenetically absent in the smaller Shenzhouraptor type.  The suture between metacarpal II and the semilunate carpal looks more obvious in the Shenzhouraptor type, but again this may be ontogenetic.  Wang et al. claim the pubis is straight in Shenzhouraptor unlike Jeholornis, but the former's type has pubes exposed in posterior view while Jeholornis' type is in side view, so their curvature isn't comparable.  Those authors also list Shenzhouraptor as differing in lacking metatarsal V, but that could easily be hidden in the single pes preserved in dorsal view.  Finally, Wang et al. claim the Jeholornis type has subequal pedal unguals II and III unlike the Shenzhouraptor type, but while all except digit IV are disarticulated in the Jeholornis type, there is a much larger ungual preserved distal to two short ones (hallux?) and proximal to four long ones (IV and III?) that would make sense as an ungual II.  In conclusion, the demonstrable differences are limited to those explainable by ontogeny (carpometacarpal fusion?; metatarsal fusion) or individual variation (caudal count; distal extent of metacarpal III; manual digit II proportions; proximodorsal ischial process expansion). Their synonymy is upheld.
Jeholornis palmapenis- O'Connor et al. (2012) listed several characters supposedly distinguishing this taxon from Jeholornis prima. The single preserved maxillary tooth and second empty alveolus contrast with IVPP V13274 (the prima holotype), V13550 and V13553, which have been reported to lack maxillary teeth. Yet jeholornithid teeth are often unpreserved due to their small size and low number, as seen by palmapenis' lack of dentary teeth (considered preservational by O'Connor et al.) and LPM 0193's (the Shenzhouraptor holotype) lack of any recognizable teeth. Even palmapenis only preserves one of the at least two maxillary teeth it had on that side. Thus the absence of maxillary teeth in other specimens may easily be preservational. The presence of two pairs of anterior dorsal pleurocoels was listed as diagnostic (grading into a single pair posteriorly), but pleurocoel number often varies between different vertebrae and even sides of the same vertebra in theropods. Anterior pleurocoel number has not been described in any other jeholornithid specimen, but IVPP V13353 shows single pairs in dorsals nine and eleven, and three pairs in ten. Until palmapenis is shown to be consistantly unique in pleurocoel number, this character is not considered diagnostic. The ilium is supposedly strongly convex dorsally, but it's clear the anterodorsal portion has merely been broken off, with no dorsal margin remaining anterior to the acetabular midpoint. The margin posterior to this is slightly convex as in other jeholornithid specimens. The anterior dorsal margin is preserved on the disarticulated left ilium, which forms a similar overall ilial dorsal convexity to other jeholornithids when rotated into place. Similarly, though the postacetabular process was described as strongly concave ventrally, the concavity is almost identical to that in IVPP V13353 (20% distance from line stretching from top of acetabulum to ventral postacetabular tip is 20% of ilial depth above acetabulum, compared to 19%) and other jeholornithids (the supposedly straight margin of IVPP V13274 looks slightly curved in the photo, and any difference would be insignificant in any case). The dorsally curved ischium was also said to be diagnostic, but the distal ischium is unpreserved in the prima holotype, with the reconstructed portion being part of the tibia or fibula instead. Indeed, O'Connor et al. state ischial curvature is unclear in other Jeholornis specimens. LPM 0193 shows a dorsally curved ischium, albeit less so than in palmapenis. In the tail, the transition point was stated to be more gradual (in central elongation) and posterior (at caudal seven instead of six) in palmapenis than IVPP V13550. Yet the transition point is also different in IVPP V13353, where the first elongated caudal is five, and IVPP V13274, where it seems to be at four (an unlabeled caudal is disarticulated adjacent to the last sacral). Differences in transition point abruptness are present as individual variation in other taxa, such as two nearly identical Microraptor specimens (CAGS 20-7-004 and 20-8-001), where the difference between lengths of caudals three and four is 9% in one and 53% in the other). Both caudal differences are thus more probably individual variation. Finally, the diagnosis lists "elongated caudals possess chevrons with hooked articulations", but these articulations are not mentioned again and photos show normal, straight dorsal, anterior and posterior ends as in other paravians. Of the diagnostic characters listed for prima by O'Connor et al., the ones not mentioned above are all unknown in palmapenis (except the robust dentary, which is true for all jeholornithids). In the text, the dentaries are said to appear unfused unlike the prima holotype, but they note this may be due to poor preservation. It may also be due to ontogeny, as palmapenis is smaller and has an unfused metatarsus. The text also states the ilium differs in having a bround rounded preacetabular process supposedly unlike IVPP V13274, but this is due to the latter being in medial view and not showing the ventral flange that would be lateral to the cuppedicus fossa, as seen in IVPP V13353 and LPM 0193. So of the listed differences from prima, only the difference in maxillary dentulousness can even be plausibly considered true and not subject to individual variation. Ironically there are some valid differences not mentioned in the text. The dentary is a third deeper than the prima holotype and IVPP V13350, which is opposite the expected trend for a juvenile. The ischium slightly expands at its tip, unlike the Shenzhouraptor holotype. But since the first difference is not observable in the Shenzhouraptor type (whose anterior dentary angles beneath the skull) and the second difference is not observable in the prima type (whose distal ischium is broken off), these would form a weak differentiation from either species. As both character states are derived in Avialae, Shenzhouraptor and prima could not be united by their counterpart states. Instead, until they are shown to have a consistant variation between multiple specimens, the differences are more readily ascribed to individual variation as is found in any theropod known from large sample sizes (Allosaurus, Tyrannosaurus, Microraptor, Archaeopteryx). Jeholornis palmapenis is here made a junior synonym of Shenzhouraptor sinensis.
References- Ji, Ji, You, Zhang, Yuan, Ji, Li and Li, 2002. Discovery of an Avialae bird - Shenzhouraptor sinensis gen. et sp. nov. - from China. Geological Bulletin of China. 21(7), 363-369.
Mortimer, DML 2002. https://web.archive.org/web/20190416181244/http://dml.cmnh.org/2002Jul/msg00671.html
Olshevsky, DML 2002. https://web.archive.org/web/20190416181245/http://dml.cmnh.org/2002Nov/msg00292.html
Wang, 2002. Fossil supports dinosaur-into-bird theory. China Daily. 07/23/2002.
Zhou and Zhang, 2002. A long-tailed, seed-eating bird from the Early Cretaceous of China. Nature. 418, 405-409.
Ji, Ji, You, Zhang, Zhang, Zhang, Yuan and Ji, 2003. An Early Cretaceous avialan bird, Shenzhouraptor sinensis from western Liaoning, China. Acta Geologica Sinica. 77(1), 21-27.
Zhou and Zhang, 2003. Jeholornis compared to Archaeopteryx, with a new understanding of the earliest avian evolution. Naturwissenschaften. 90, 220-225.
Yuan and Ji, 2004. New abnatomical observation of Shenzhouraptor sinensis (Avialae) of Jehol biota from China and cursorial origin of avian flight. Journal of Vertebrate Paleontology. 24(3), 245A.
Chiappe and Dyke, 2006. The early evolutionary history of birds. Journal of the Palaontological Society of Korea. 22(1), 133-151.
Zhou and Zhang, 2006. Mesozoic birds of China- A synoptic review. Vertebrata PalAsiatica. 44(1), 74-98.
Li and Zhang, 2008. Reconstructing the habits of Jeholornis prima. SAPE 2008 abstracts. 11.
Erickson, Rauhut, Zhou, Turner, Inouye, Hu and Norell, 2009. Was dinosaurian physiology inherited by birds? Reconciling slow growth in Archaeopteryx. PLoS ONE. 4(10), e7390.
Li, Sullivan, Zhou and Zhang, 2010. Basal birds from China: A brief review. Chinese Birds. 1(2), 83-96.
O'Connor, Sun, Xu, Wang and Zhou, 2012. A new species of Jeholornis with complete caudal integument. Historical Biology. 24(1), 29-41.
Wang, O'Connor and Zhou, 2014. A new robust enantiornithine bird from the Lower Cretaceous of China with scansorial adaptations. Journal of Vertebrate Paleontology. 34(3), 657-671.
Zheng, O'Connor, Wang, Wang, Zhang and Zhou, 2014. On the absence of sternal elements in Anchiornis (Paraves) and Sapeornis (Aves) and the complex early evolution of the avian sternum. Proceedings of the National Academy of Sciences. 111(38), 13900-13905.
Wu, Bailleul, Li, O'Connor and Zhou, 2021. Osteohistology of the scapulocoracoid of Confuciusornis and preliminary analysis of the shoulder joint in Aves. Frontiers in Earth Science. 9, 617124.
Wang, Huang, Kundr�t, Cau, Liu, Wang and Ju, 2020. A new jeholornithiform exhibits the earliest appearance of the fused sternum and pelvis in the evolution of avialan dinosaurs. Journal of Asian Earth Sciences. 199, 104401.
Hu, Wang, McDonald, Wroe, O'Connor, Bjarnason, Bevitt, Yin, Zheng, Zhou and Benson, 2022. Earliest evidence for frugivory and seed dispersal by birds. eLife. 11:e74751.

Euavialae Ji, Ji, Zhang, You, Zhang, Wang, Yuan and Ji, 2002
= Avebrevicauda sensu Agnolin and Novas, 2013
Definition- (Passer domesticus <- Jeholornis prima, Rahonavis ostromi) (modified)
Diagnosis- dorsal premaxillary process extends to anterior edge of orbit (unknown in Shenzhouraptor; absent in most enantiornithines and Archaeorhynchus); quadrate not pneumatic (also in Epidexipteryx, Dromaeosauridae and many other taxa; absent in Patagopteryx, Ichthyornis and Aves); dentary strongly forked posteriorly (also in oviraptorosaurs and Epidexipteryx; absent in most ornithothoracines); at least seven sacral vertebrae (also in Parvicursorinae, some caenagnathoids and Epidexipteryx); less than twenty-three caudal vertebrae (also in Caudipteryx, Epidexipteryx and some Archaeopteryx specimens; absent in Jixiangornis and Yandangornis); pygostyle (also in Beipiaosaurus, Similicaudipteryx and Nomingia; absent in Jixiangornis and Yandangornis); humeral distal condyles developed on anterior surface (also in Sinosauropteryx, Therizinosauria, Alvarezsauridae and Bambiraptor); brevis fossa absent on ilium (also in some therizinosaurids; absent in Patagopteryx); astragalocalcaneum fused to tibia (also in derived alvarezsaurids, Pedopenna and Microraptor; absent in Vorona, Paraprotopteryx, Hebeiornis and Gobipteryx- ontogenetic?).
Comments- This name was used in a figure by Ji et al. (2002) for a clade containing Jixiangornis and Pygostylia, but not Shenzhouraptor or Archaeopteryx.
While it seems logical that the long-tailed, pygostyle-less Jixiangornis, Yandangornis and Dalianraptor are more basal than omnivoropterygids, the total character evidence may suggest otherwise. For instance, Jixiangornis and Dalianraptor have narrower interclavicular angles like ornithothoracines. Jixiangornis has a mobile scapulocoracoid (as in Shenzhouraptor and ornithothoracines). Yandangornis has posterolateral sternal processes which extend posteriorly to level of the median sternal edge, as in most ornithothoracines. None of these characters are found in omnivoropterygids or confuciusornithids.
The posteriorly extensive dorsal premaxillary processes were reported as absent in Sapeornis and Zhongjianornis, but my examination of figures suggests they were misidentified as nasals.
References- Ji, Ji, Zhang, You, Zhang, Wang, Yuan and Ji, 2002. A new avialian bird - Jixiangornis orientalis gen. et sp. nov. - from the Lower Cretaceous of western Liaoning, NE China. Journal of Nanjing University (Natural Sciences). 38(6), 723-736.

Bauxitornis Dyke and Osi, 2010
B. mindszentyae Dyke and Osi, 2010
Santonian, Late Cretaceous
Csehbanya Formation, Hungary
Holotype- (MTM V 2009.38.1; = MTM Gyn 439) incomplete tarsometatarsus (51 mm)
Diagnosis- (after Dyke and Osi, 2010) marked scar (tubercle) for M. tibialis cranialis absent; metatarsal II shorter than III or IV; metatarsal IV extends farther distally than mt III.
Comments- Discovered between 2002 and 2004, this specimen was first noted in an abstract (Osi, 2004), described as Enantiornithes indet. by Osi (2008), then named as the new taxon of avisaurid enantiornithine Bauxitornis mindszentyae by Dyke and Osi (2010). Cau (online, 2010) found that while most parsimoniously an enantiornithine, Bauxitornis could also form the sister group to the similar Romanian paravian Balaur with one additional step. It is here referred to Euavialae incertae sedis pending further study.
References- Osi, 2004. Enantiornithine bird remains from the Late Cretaceous of Hungary. Sixth International Meeting of the Society of Avian Palaeontology and Evolution, Abstracts. 50.
Osi, 2008. Enantiornithine bird remains from the Late Cretaceous of Hungary. Oryctos. 7, 55-60.
Cau, online 2010. http://theropoda.blogspot.com/2010/09/balaur-more-than-just-double-sickle.html
Dyke and Osi, 2010. A review of Late Cretaceous fossil birds from Hungary. Geological Journal. 45(4), 434-444.

unnamed euavialan (Dettmann, Molnar, Douglas, Burger, Fielding, Clifford, Francis, Jell, Rich, Wade, Rich, Pledge, Kemp and Rozefelds, 1992)
Albian, Early Cretaceous
New Field, Griman Creek Formation, New South Wales, Australia
Material- (AM F102786) distal tibiotarsus (7.2 mm wide) (Dettmann, Molnar, Douglas, Burger, Fielding, Clifford, Francis, Jell, Rich, Wade, Rich, Pledge, Kemp and Rozefelds, 1992)
(AM F102787) distal tibiotarsus (7.6 mm wide) (Dettmann, Molnar, Douglas, Burger, Fielding, Clifford, Francis, Jell, Rich, Wade, Rich, Pledge, Kemp and Rozefelds, 1992)
Albian, Early Cretaceous
Lightning Ridge, Griman Creek Formation, New South Wales, Australia
?(private coll.; cast QM F37912) distal tibiotarsus (26.7 mm wide) (Molnar, 1999)
Diagnosis- (after Molnar, 1999) posterolateral edge of distal tibiotarsal shaft sharpened to form a ridge; fossa on medial face of medial tibiotarsal condyle.
Comments- Discovered in 1991, AM F102786 and F102787 were first mentioned in a "Note added in proof" in Dettmann et al. (1992) as "distal ends of tibiotarsi about the same size as those of Nanantius eos, but quite
different in form" which "most resemble those of Baptornis, but a phylogenetic analysis has yet to be carried out."  Molnar (1999) described them in detail and suggested they (considered as a single taxon but "sufficiently different as probably not to have come from the same individual") were non-enantiornithine, non-ornithuromorph ornithothoracines. The lack of a fibular articulation is similar to derived avialans and the complete fusion suggests a euavialan. The lack of a supratendinal bridge excludes it from Ornithurae. The small medial condyle excludes it from Enantiornithes, though taxa such as Yandangornis and Longicrusavis are similar. The distally rounded condyles are also unlike all but the most basal enantiornithines. The lack of any proximal extent to the articular surface posteriorly is unlike pygostylians. These are thus most parsimoniously from a non-pygostylian euavialan.
Molnar (1999) also described cast QM F37912, considered to perhaps be "a larger individual of the same taxon" or "represent a distinct, larger taxon."  He stated it shared the posterolateral ridge and medial fossa with the smaller tibiotarsi, but noted "The ridge differs in profile, the medial condyle is more roller-like in form and markedly more robust and the intercondylar sulcus is more pronounced."  The same characters as described above would also make this a non-pygostylian euavialan.
References- Dettmann, Molnar, Douglas, Burger, Fielding, Clifford, Francis, Jell, Rich, Wade, Rich, Pledge, Kemp and Rozefelds, 1992. Australian Cretaceous terrestrial faunas and floras: Biostratigraphic and biogeographic implications. Cretaceous Research. 13, 207-262.
Molnar, 1999. Avian tibiotarsi from the Early Cretaceous of Lightning Ridge, N.S.W. In Tomida, Rich and Rich (eds). Proceedings of the Second Gondwanan Dinosaur Symposium, National Sciences Museum Monographs. 15, 197-209.

Balaur Csiki, Vremir, Brusatte and Norell, 2010
B. bondoc Csiki, Vremir, Brusatte and Norell, 2010
Maastrichtian, Late Cretaceous
Sebes Formation, Romania
Holotype- (EME PV.313) (7+ year old adult) anterior dorsal vertebra (12 mm), posterior dorsal vertebral fragment, incomplete posterior dorsal vertebra (14 mm), posterior dorsal vertebra (16 mm), incomplete posterior dorsal vertebra (15 mm), incomplete posterior dorsal vertebra (14 mm), posterior dorsal vertebra (11 mm), posterior dorsal vertebra (12 mm), several incomplete posterior dorsal ribs, incomplete synsacrum, first caudal vertebra, second caudal vertebra (17 mm), third caudal vertebra (19 mm), fourth caudal vertebra, proximal caudal vertebra (22 mm), ~eighth caudal vertebra (26 mm), scapulocoracoids (one incomplete, one partial), sternal plates, humeri (117 mm), radii (95 mm), ulnae (99 mm), carpometacarpi (one incomplete; I 18, II 41, III 39 mm), phalanges I-1 (40 mm), manual unguals I (37 mm straight), phalanges II-1 (31 mm), phalanges II-2 (38 mm), manual unguals II, phalanx III-1 (11 mm), incomplete pelves, tibiofibulotarsus (153 mm), metatarsal I (37 mm), phalanx I-1 (23 mm), pedal ungual I (33 mm), tarsometatarsi (II 52, III 61, IV 53, V 18 mm), phalanx II-1 (13 mm), phalanx II-2 (22 mm), pedal ungual II (42 mm), phalanx III-1 (21 mm), phalanx III-2 (15 mm), phalanx III-3 (19 mm), pedal ungual III (24 mm), phalanx IV-1 (14 mm), phalanx IV-2 (11 mm), phalanx IV-3 (11 mm), phalanx IV-4 (12 mm), pedal ungual IV (19 mm)
Maastrichtian, Late Cretaceous
Densus-Ciula Formation, Romania
Paratypes- ?(FGGUB R.1580) (6+ year old adult) incomplete humerus (~170 mm) (Csiki and Grigorescu, 2005)
....(FGGUB R.1581) ulna (~163 mm) (Csiki and Grigorescu, 2005)
....(FGGUB R.1582) proximal manual phalanx I-1 or II-1 (Csiki and Grigorescu, 2005)
....(FGGUB R.1583) proximal manual phalanx I-1 (Csiki and Grigorescu, 2005)
....(FGGUB R.1584) distal manual phalanx II-2 (Csiki and Grigorescu, 2005)
....(FGGUB R.1585) incomplete metacarpal II (Csiki and Grigorescu, 2005)
Diagnosis- (after Csiki et al., 2010b) sinuous ridge on lateral surface of distal humerus extends for 1/3 of the length of the bone; prominent ridge on medial surface of distal half of humerus; anterior surface of ulna flattened and bisected by longitudinal ridge; reduced, splint-like metacarpal III; dorsolateral intermetacarpal ridge on metacarpal II; manual ungual II with Y-shaped lateral and medial grooves; phalanges of manual digit III reduced and digit nonfunctional (also in Sapeornis and Ornithothoraces); extremely retroverted pubes and ischia whose long axes are nearly horizontal (taphonomic?); ischial obturator tuberosity expressed as enlarged, thin flange that contacts or nearly contacts pubis ventrally; tarsometatarsus substantially wider (1.5x) than distal tibiotarsus; robust ridges on plantar surfaces of metatarsals II-IV; metatarsals II and III not ginglymoid; articular region of mts II-III narrower than entire distal end; metatarsal V fused with tarsometatarsus; short, hook-like mt V.
Other diagnoses- Many of Csiki et al.'s (2010b) listed autapomorphies for Balaur are plesiomorphic when considered as an anialan instead of a dromaeosaurid- hypertrophied coracoid tubercle; fused carpometacarpus; distal articular surface not extending onto ventral faces of metacarpals I and II; metacarpal III contacting metacarpal II distally; fused tarsometatarsus; first digit of pes functional with enlarged phalanges but vestigial metatarsal I. Csiki et al. listed two other supposed autapomorphies- pubic peduncle laterally everted such that broad cuppedicus fossa faces laterally and dorsally; pubis reoriented so that lateral surface faces ventrally and pubic tubercle located directly below acetabulum. Brusatte et al. (2013) determined these were both due to the pelvis being crushed.
Comments- The paratypes were discovered in 1997 and briefly noted by Csiki and Grigorescu (2005) as the remains of a caenagnathid. Brusatte et al. (2013) referred them to Balaur sp. nov., based on their larger size and different locality, though no anatomical differences were noted. The holotype was discovered in 2009, noted in an abstract by Csiki et al. (2010a), and described by Csiki et al. (2010b) as a new taxon of dromaeosaurid sister to Velociraptor. However, Cau (online, 2010), Godefroit et al. (2013) and Dyke et al. (2014) noted that several of its supposed autapomorphies are also present in birds, which was expanded on by Cau et al. (2015). The latter modified Brusatte et al.'s TWG matrix and also used Cau's matrix as did Godefroit et al., finding it takes 3-10 steps to move Balaur back to Dromaeosauridae depending on the analysis. Within Avialae, Balaur is sister to Avebrevicauda in Cau's trees, the bjust closer to Aves than Archaeopteryx in Foth et al. (2014) and an omnivoropterygid in the modified Brusatte et al. tree.
References- Csiki and Grigorescu, 2005. A new theropod from Tustea: Are there oviraptorosaurs in the Upper Cretaceous of Europe? Kaupia. 14, 78.
Cau, online 2010. http://theropoda.blogspot.com/2010/08/quello-che-gli-altri-non-vi-diranno-su.html
Csiki, Brusatte, Vremir and Norell, 2010a. Being a theropod on an island: A peculiar dromaeosaurid from the Maastrichtian of the Transylvanian Basin, Romania. Journal of Vertebrate Paleontology. Program and Abstracts 2010, 76A.
Csiki, Vremir, Brusatte and Norell, 2010b. An aberrant island-dwelling theropod dinosaur from the Late Cretaceous of Romania. Proceedings of the National Academy of Sciences. 107(35), 15357-15361.
Brusatte, Vremir, Csiki-Sava, Turner, Watanabe, Erickson and Norell, 2013. The osteology of Balaur bondoc, an island-dwelling dromaeosaurid (Dinosauria: Theropoda) from the Late Cretaceous of Romania. Bulletin of the American Museum of Natural History. 374, 1-100.
Godefroit, Cau, Hu, Escuillie, Wu and Dyke, 2013. A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds. Nature. 498, 359-362.
Dyke, Cau, Naish, Brougham and Godefroit, 2014. Archaeopteryx and paravian phylogeny: The enigma of Balaur. Journal of Vertebrate Paleontology. Program and Abstracts 2014, 123.
Foth, Tischlinger and Rauhut, 2014. New specimen of Archaeopteryx provides insights into the evolution of pennaceous feathers. Nature. 511, 79-82.
Cau, Brougham and Naish, 2015. The phylogenetic affinities of the bizarre Late Cretaceous Romanian theropod Balaur bondoc (Dinosauria, Maniraptora): Dromaeosaurid or flightless bird? PeerJ. 3, e1032.

Fukuipteryx Imai, Azuma, Kawabe, Shibata, Miyata, Wang and Zhou, 2019b
F. prima Imai, Azuma, Kawabe, Shibata, Miyata, Wang and Zhou, 2019b
Middle-Late Aptian, Early Cretaceous
Kitadani quarry, Kitadani Formation, Japan
Holotype- (FPDM-V-9769) (<1 year old subadult) incomplete surangular, cranial fragments, two cervical centra, two anterior-mid dorsal vertebrae, posterior dorsal centrum, posterior dorsal neural arch, five partial dorsal ribs, two partial synsacral vertebrae, five caudal vertebrae, pygostyle (26 mm), incomplete furcula, coracoids One incomplete, one distal), humerus (75 mm), radii, ulnae (one incomplete; 71 mm), phalanx I-1, metacarpal II (31 mm), phalanx II-2, manual ungual II, metacarpal III, phalanx III-3, manual ungual III, incomplete ilium, femora (58 mm), incomplete tibiae, metatarsal II, partial metatarsal III, metatarsals IV (one incomplete)
Diagnosis- (after Imai et al., 2019b) robust pygostyle with incipient spinal processes and paddle-like structure at distal end; semicircular depression on anterodorsal corner of humeral head; dorsally bowed humeral shaft.
Comments- This was discovered in 2013 and initially announced as a probably non-ornithothoracine bird by Imai et al. (2016). 
Imai et al. (2020) added it to O'Connor's avialan matrix and recovered it as more derived than Archaeopteryx but outside Jeholornithidae plus Pygostylia.
References- Imai, Azuma, Shibata and Miyata, 2016. Report on a fossil bird from the Lower Cretaceous Kitadani Formation, Tetori Group, Fukui, Japan. Journal of Vertebrate Paleontology. Program and Abstracts, 159-160.
Imai, Azuma, Kawabe, Shibata, Miyata, Wang and Zhou, 2019a. First non-ornithothoracine fossil bird (Theropoda, Avialae) from the Early Cretaceous of Japan: Increasing our understanding about evolution and paleobiogeography of stem birds. Journal of Vertebrate Paleontology. Program and Abstracts, 123.
Imai, Azuma, Kawabe, Shibata, Miyata, Wang and Zhou, 2019b. An unusual bird (Theropoda, Avialae) from the Early Cretaceous of Japan suggests complex evolutionary history of basal birds. Communications Biology. 2:399.

Hesperonychus Longrich and Currie, 2009
H. elizabethae Longrich and Currie, 2009
Late Campanian, Late Cretaceous
Dinosaur Park Formation of the Judith River Group, Alberta, Canada
Holotype- (UALVP 48778) (1.6 kg) partial ilia, pubes (95 mm)
Referred- (RTMP 1988.36.68) pedal ungual II (Longrich and Currie, 2009)
(RTMP 1989.116.65) pedal phalanx II-1 (14.2 mm) (Longrich and Currie, 2009)
(RTMP 1991.50.105) incomplete pedal ungual II (Longrich and Currie, 2009)
(RTMP 2000.12.100) incomplete pedal ungual II (Longrich and Currie, 2009)
(UALVP 50686; = UALVP 50048 in supplementary info?) pedal ungual II (Longrich and Currie, 2009)
(UALVP 50687; = UALVP 50049 in supplementary info?) incomplete pedal phalanx II-1 (Longrich and Currie, 2009)
Late Campanian, Late Cretaceous
Oldman Formation of the Judith River Group, Alberta, Canada
Referred- (RTMP 1995.92.9) pedal ungual II (Longrich and Currie, 2009)
Late Campanian, Late Cretaceous
Judith River Group, Alberta, Canada
Referred- (RTMP 1966.19.22) incomplete pedal phalanx II-1 (Longrich and Currie, 2009)
(RTMP 1979.10.6) pedal ungual II (Longrich and Currie, 2009)
(RTMP 1980.8.205) pedal ungual II (Longrich and Currie, 2009)
(RTMP 1980.16.1880) pedal ungual II (Longrich and Currie, 2009)
(RTMP 1983.67.7) pedal phalanx II-2 (17.1 mm) (Longrich and Currie, 2009)
(RTMP 1988.50.34) pedal ungual II (Longrich and Currie, 2009)
(RTMP 1990.107.15) pedal ungual II (Longrich and Currie, 2009)
(RTMP 1991.50.143) pedal phalanx II-2 (4.8 mm) (Longrich and Currie, 2009)
(RTMP 1992.36.61; = RTMP 1992.36.31 in supplementary info) pedal phalanx II-2 (11.1 mm) (Longrich and Currie, 2009)
Diagnosis- (after Longrich and Currie, 2009) pubic peduncle of ilium with medial surface deeply excavated; postacetabular process of ilium with medial shelf split to form anterior and posterior processes; lateral tubercles of pubis wing-like and curving anteriorly; pubis with fossa on lateral surface ventral to acetabulum; pubic apron shifted onto posterior surface of pubis; pubic symphysis teardrop-shaped in lateral view; ischial peduncle of pubis reduced to a narrow lamina.
Comments- Several of the referred specimens are only listed in the electronic supplementary material, not the hypodigm of the article.
While generally referred to Microraptoria, Hartman et al. (2019) recovered this as an avialan close to Balaur.
References- Longrich and Currie, 2009. A microraptorine (Dinosauria–Dromaeosauridae) from the Late Cretaceous of North America. Proceedings of the National Academy of Sciences. 106(13), 5002-5007.
Hartman, Mortimer, Wahl, Lomax, Lippincott and Lovelace, 2019. A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ. 7:e7247. DOI: 10.7717/peerj.7247

undescribed Jeholornithidae (O'Connor, Wang, Sullivan, Zheng, Tubaro, Zhang and Zhou, 2013)
Barremian-Aptian, Early Cretaceous
Chaoyang, Yixian Formation, Liaoning, China
(STM 2-51) (adult female, ~690 g) fragmentary skull, cervical vertebrae, dorsal vertebrae, dorsal ribs, caudal vertebrae, scapula, humeri (118.3 mm), radii, ulnae, metacarpal I, phalanx I-1, manual ungual I, carpometacarpus, phalanx II-1, phalanx II-2, manual ungual II, femora (88 mm), tibiotarsi, metatarsals I, phalanx I-1, pedal ungual I, tarsometatarsi, phalanx II-1, phalanx II-2, pedal ungual II, phalanx III-1, phalanx III-2, phalanx III-3, pedal ungual III, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, ovarian follicles (Zheng et al., 2013)
Barremian-Albian, Early Cretaceous
Jehol Group, Liaoning, China
Material- (STM 2-1) incomplete skeleton including femur (55 mm) (Zheng et al., 2014)
(STM 2-2) material including femur (76 mm) (Zheng et al., 2014)
(STM 2-5) incomplete skeleton including gastralia, sternum femur (70 mm) and feathers (Zheng et al., 2014)
(STM 2-3) material including partial femur (Zheng et al., 2014)
(STM 2-4) incomplete skeleton including femur (85 mm) and feathers (Zheng et al., 2014)
(STM 2-6) incomplete skeleton including gastralia, sternum, femur (75 mm) and feathers (Zheng et al., 2014)
(STM 2-7) incomplete skeleton including five rows of gastralia, sternum, femur (67 mm) and feathers (Zheng et al., 2014)
(STM 2-8) incomplete skeleton including eight rows of gastralia, sternum, femur (68.8 mm), remiges and retrices (O'Connor et al., 2013)
(STM 2-9) incomplete skeleton including sternum, femur (56 mm) and feathers (Zheng et al., 2014)
(STM 2-10) incomplete skeleton including five rows of gastralia, sternum and femur (54 mm) (Zheng et al., 2014)
(STM 2-11) posterior skull, mandibles, cervical vertebrae, dorsal vertebrae, dorsal ribs, sacrum, caudal series, scapulae, humeri, radii, ulnae, semilunate carpals, metacarpal I, phjalanges I-1, manual unguals I, carpometacarpi, phalanges II-1, phalanges II-2 (one proximal), phalanx III-3, ilium, pubes, femora (47.6 mm), tibiotarsi, tarsometatarsi, pedal phalanges, pedal unguals, body feathers, remiges and retrices (O'Connor et al., 2013)
(STM 2-12) incomplete skeleton including sternum and femur (70 mm) (Zheng et al., 2014)
(STM 2-13) material including gastralia, sternum, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 2-14) incomplete skeleton including sternum and femur (58 mm) (Zheng et al., 2014)
(STM 2-15) incomplete skeleton including femur (80 mm), feathers and gastroliths (Zheng et al., 2014)
(STM 2-16) incomplete skeleton including gastralia, sternum and partial femur (Zheng, Wang, O'Connor and Zhou, 2012)
(STM 2-17) material including gastralia, femur (57 mm) and feathers (Zheng et al., 2014)
(STM 2-18) skull, mandible, cervical series, dorsal series, dorsal ribs, five rows of gastralia, sacrum?, caudal series, furcula, scapulae, humeri, partial radii, ulnae, pisiform, metacarpals I, phalanges I-1, manual unguals I, carpometacarpi, phalanges II-1, phalanges III-X,  femora (55 mm), tibiotarsi, tarsometatarsi, pedal phalanges, pedal unguals, remiges, proximal caudal fan and retrices (O'Connor et al., 2013)
(STM 2-19) material including gastralia, ?sternum, femur (77 mm) and feathers (Zheng et al., 2014)
(STM 2-20) material including gastralia, sternum and femur (73 mm) (Zheng et al., 2014)
(STM 2-21) incomplete skeleton including gastralia and femur (78 mm) (Zheng et al., 2014)
(STM 2-22) material (Zheng et al., 2014)
(STM 2-23) incomplete skeleton including femur (77 mm), remiges and retrices (O'Connor et al., 2013)
(STM 2-24) incomplete skeleton including gastralia, sternum, femur (100 mm) and feathers (Zheng et al., 2014)
(STM 2-25) incomplete skeleton including gastralia, sternum, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 2-26) incomplete skeleton including sternum and femur (70 mm) (Zheng et al., 2014)
(STM 2-27) incomplete skeleton including partial femur and feathers (Zheng et al., 2014)
(STM 2-28) incomplete skeleton including sternum (Zheng et al., 2014)
(STM 2-29) incomplete skeleton including gastralia, sternum, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 2-30) incomplete skeleton including femur (75 mm) (Zheng et al., 2014)
(STM 2-31) incomplete skeleton including sternum, partial femur and feathers (Zheng et al., 2014)
(STM 2-32) incomplete skeleton including gastralia and femur (60 mm) (Zheng et al., 2014)
(STM 2-33) incomplete skeleton including sternum and femur (66 mm) (Zheng et al., 2014)
(STM 2-34) incomplete skeleton including gastralia, sternum, femur (59 mm) and feathers (Zheng et al., 2014)
(STM 2-35) incomplete skeleton including sternum and femur (79 mm) (Zheng et al., 2014)
(STM 2-36) incomplete skeleton including gastralia, sternum, femur (66 mm) and feathers  (Zheng et al., 2014)
(STM 2-37) dorsal vertebrae, gastralia, synsacrum, proximal caudal vertebrae, furcula, scapulae, humeri, radii, ulnae, scapholunare, pisiforms, metacarpals I, phalanx I-1, manual ungual I, carpometacarpi, phalanges II-1, phalanges II-2, manual unguals II, phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III, pubes (one distal), ischium, femora (71 mm), tibiotarsi, fibula, metatarsals, I , phalanges I-1, pedal unguals I, tarsometatarsi, phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, remiges and retrices (O'Connor et al., 2013)
(STM 2-38) incomplete skeleton including gastralia, sternum, femur (80 mm) and feathers (Zheng et al., 2014)
(STM 2-39) incomplete skeleton including sternum and femur (68 mm) (Zheng, Wang, O'Connor and Zhou, 2012)
(STM 2-40) material including gastralia and femur (64 mm) (Zheng et al., 2014)
(STM 2-41) incomplete skeleton including gastralia, sternum, femur (60 mm) and seeds (Zheng et al., 2014)
(STM 2-42) material including sternum and femur (63 mm) (Zheng et al., 2014)
(STM 2-44) material including feathers (Zheng et al., 2014)
(STM 2-45) incomplete skeleton including femur (53 mm) and feathers (Zheng et al., 2014)
(STM 2-46) incomplete skeleton including sternum, femur (79 mm) and feathers (Zheng et al., 2014)
(STM 2-47) incomplete skeleton including gastralia, sternum and femur (75 mm) (Zheng et al., 2014)
(STM 2-48) material including femur (58 mm) (Zheng et al., 2014)
(STM 2-49) incomplete skeleton including scapula, coracoid, sternum, manual ungual and femur (75 mm) (Zheng et al., 2014)
(STM 2-50) incomplete skeleton including partial femur (Zheng et al., 2014)
(STM 2-51) (adult female, ~690 g) fragmentary skull, cervical vertebrae, dorsal vertebrae, dorsal ribs, caudal vertebrae, scapula, humeri (118.3 mm), radii, ulnae, metacarpal I, phalanx I-1, manual ungual I, carpometacarpus, phalanx II-1, phalanx II-2, manual ungual II, femora (70 mm), tibiotarsi, metatarsals I, phalanx I-1, pedal ungual I, tarsometatarsi, phalanx II-1, phalanx II-2, pedal ungual II, phalanx III-1, phalanx III-2, phalanx III-3, pedal ungual III, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, ovarian follicles (Zheng et al., 2013)
(STM 2-52) material including gastralia and femur (59 mm) (Zheng et al., 2014)
(STM 2-53) material including partial femur (Zheng et al., 2014)
(STM 2-54) incomplete skeleton including gastralia and femur (73 mm) (Zheng et al., 2014)
(STM 2-55) incomplete skeleton including femur (56 mm) (Zheng et al., 2014)
(STM 3-1) material including femur (66 mm) (Zheng et al., 2014)
(STM 3-2) material including sternum and femur (71 mm) (Zheng et al., 2014)
(STM 3-3) skull, mandible, cervical series, dorsal series, dorsal ribs, gastralia, caudal series, chevrons, sternal ribs, ilia, pubes, ischia, femora (64 mm), tibiae, metatarsals I, phalanges I-1, pedal; unguals I, tarsometatarsi, phalanges II-1, phalanges II-2, pedal unguals II, phalanx III-1, phalanx III-2, phalanges III-3, pedal unguals III, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanges IV-4, pedal unguals IV, proximal caudal fan (O'Connor et al., 2013)
(STM 3-4) specimen including skull, cervical series, dorsal ribs, gastralia, caudal series, femora (58 mm), tibiae, metatarsi, pedal phalanges, proximal caudal fan and retrices (O'Connor et al., 2013)
(STM 3-5) material including femur (55 mm) (Zheng et al., 2014)
(STM 3-6) material including gastralia and femur (65 mm) (Zheng et al., 2014)
(STM 3-7) material including gastralia and femur (77 mm) (Zheng et al., 2014)
(STM 3-9) material including femur (60 mm) (Zheng et al., 2014)
(STM 3-10) material (Zheng et al., 2014)
(STM 3-11) material including femur (68 mm) (Zheng et al., 2014)
(STM 3-12) material (Zheng et al., 2014)
(STM 3-13) material including femur (58 mm) (Zheng et al., 2014)
(STM 3-14) material (Zheng et al., 2014)
(STM 3-15) material including femur (73 mm) (Zheng et al., 2014)
(STM 3-16) incomplete skeleton including six rows of gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 3-17) material including sternum and femur (75 mm) (Zheng et al., 2014)
(STM 3-18) material (Zheng et al., 2014)
(STM 3-19) material including gastralia and femur (54 mm) (Zheng et al., 2014)
(STM 3-20) material including gastralia, femur (76 mm) and feathers (Zheng et al., 2014)
(STM 3-21) mterial including femur (58 mm) and feathers (Zheng et al., 2014)
(STM 3-22) material including femur (61 mm) (Zheng et al., 2014)
(STM 3-23) material; including gastralia and femur (73 mm) (Zheng et al., 2014)
(STM 3-24) material (Zheng et al., 2014)
(STM 3-25) material including gastralia, femur (80 mm) and feathers (Zheng et al., 2014)
(STM 3-26) material including femur (54 mm) (Zheng et al., 2014)
(STM 3-27) incomplete skeleton including femur (70 mm) (Zheng et al., 2014)
(STM 3-28) material including femur (75 mm) and feathers (Zheng et al., 2014)
(STM 3-29) material (Zheng et al., 2014)
(STM 3-30) specimen including femur (57 mm) and retrices (O'Connor et al., 2013)
(STM 3-31) material including gastralia and femur (50 mm) (Zheng et al., 2014)
(STM 3-32) material including gastralia and femur (68 mm) (Zheng et al., 2014)
(STM 3-33) material including gastralia and femur (75 mm) (Zheng et al., 2014)
Comments- STM 2-16 and 2-39 (Zheng et al., 2012) are possibly Jixiangornis as both have sterna which "preserve clefts on the rostral and caudal midline connected by a visible medial suture."
Zheng et al. (2013) describe a specimen with ovarian follicles as Jeholornis sp., but their supporting characters (large size; dorsoventrally deep skull; elongate bony tail formed by more than 20 free caudal vertebrae; proximally straight ulna; large intermetacarpal space formed by lateral curvature of metacarpal III; three large, recurved manual unguals; tarsometatarsus proportionately short) are also found in Jixiangornis. O'Connor et al. (2014) later described its histology.
Similarly, O'Connor et al. (2013) refer specimens to Jeholornis based on "their short and deep skull with small peg-like reduced dentition and triangular mandibles, elongate boney tail composed of ∼27 free vertebrae with transition point at the fifth/sixth caudal, curved scapula, and unreduced manus with three claws", which are also true in Jixiangornis (except perhaps the dentition).  Of those specimens, STM 2-18 may be Jixiangornis based on low interclavicular angle; STM 2-37 may be Jixiangornis based on low interclavicular angle and furcular arms expanded in the middle.  Of specimens listed by Zheng et al. (2014), STM 2-49 may be Jixiangornis based on its procoracoid process. 
References- Zheng, Wang, O'Connor and Zhou, 2012. Insight into the early evolution of the avian sternum from juvenile enantiornithines. Nature Communications. 3, 1116.
O'Connor, Wang, Sullivan, Zheng, Tubaro, Zhang and Zhou, 2013. Unique caudal plumage of Jeholornis and complex tail evolution in early birds. Proceedings of the National Academy of Sciences. 110(43), 17404-17408.
Zheng, O'Connor, Huchzermeyer, Wang, Wang, Wang and Zhou, 2013. Exceptional preservation of ovarian follicles in Early Cretaceous birds and implications for early evolution of avian reproductive behaviour. Nature. 495, 507-511.
O'Connor, Wang, Zheng, Wang and Zhou, 2014. The histology of two female Early Cretaceous birds. Vertebrata PalAsiatica. 52(1), 112-128.
Zheng, O'Connor, Wang, Wang, Zhang and Zhou, 2014. On the absence of sternal elements in Anchiornis (Paraves) and Sapeornis (Aves) and the complex early evolution of the avian sternum. Proceedings of the National Academy of Sciences. 111(38), 13900-13905.
Hu, Wang, McDonald, Wroe, O'Connor, Bjarnason, Bevitt, Yin, Zheng, Zhou and Benson, 2022. Earliest evidence for frugivory and seed dispersal by birds. eLife. 11:e74751.

Jixiangornis Ji, Ji, Zhang, You, Zhang, Wang, Yuan and Ji, 2002
= "Luckyraptor" Zhang, 2007
= Kompsornis Wang, Huang, Kundr�t, Cau, Liu, Wang and Ju, 2020
J. orientalis Ji, Ji, Zhang, You, Zhang, Wang, Yuan and Ji, 2002
= "Luckyraptor eastensis" Zhang, 2007
= Jeholornis curvipes Lefevre, Hu, Escuillie, Dyke and Godefroit, 2014
= Kompsornis longicaudus Wang, Huang, Kundr�t, Cau, Liu, Wang and Ju, 2020
Late Barremian-Early Aptian, Early Cretaceous
Jianshangou Beds of Yixian Formation, Liaoning, China
Holotype- (CDPC-02-04-001; material of "Luckyraptor eastensis") skull (80.7 mm), mandibles, hyoid, nine cervical vertebrae (12.5, 13.3, 14.8 mm), eight dorsal vertebrae (8-9 mm), eight pairs of dorsal ribs, uncinate processes, thirteen to fourteen rows of gastralia, sacrum (43 mm), twenty-seven caudal vertebrae (sixth caudal vertebra 18.6 mm, seventh caudal vertebra 20.7 mm, eighth caudal vertebra 21.2 mm, ninth caudal vertebra 22.4 mm), chevrons, partial scapula, coracoids (39.5, 40.6 mm), furcula, incomplete sternum, four to five sternal ribs, humeri (112 mm), radii (one partial; 103.4 mm), ulnae (one partial; 107.1 mm), scapholunare, semilunate carpal, metacarpal I (11.3 mm), phalanx I-1 (28 mm), manual ungual I, metacarpal II (44.9 mm), phalanx II-1 (22.7 mm), phalanx II-2 (21.1 mm), manual ungual II (18.5 mm), metacarpal III (47.2 mm), phalanx III-2 (12.3 mm), manual ungual III (10.2 mm), ilium (28 mm), pubes (36.6 mm), ischium, femora (71.9 mm), tibiotarsi (83.2, 83 mm), fibulae (67.7, 55.6 mm), metatarsals I (10.5, 9.2 mm), phalanges I-1 (9.3 mm), pedal unguals I (15.6, 14.1 mm), tarsometatarsus (II 38.7 mm, III 41.3 mm, IV 39.8 mm), phalanges II-1 (9.3 mm), phalanges II-2 (13.7, 12.9 mm), pedal unguals II (23.4 mm), phalanges III-1, phalanges III-2, (11.9, 12.6 mm), phalanges III-3 (12.9, 12.2 mm), pedal unguals III (19.4 mm), phalanges IV-1 (9.4 mm), phalanges IV-2 (7.9, 8.5 mm), phalanges IV-3 (6.8, 7 mm), phalanges IV-4 (10.5, 10.5 mm), pedal unguals IV (16.1 mm), retrices
Referred- (CAGS coll.) specimen including posterior cervical vertebrae, dorsal ribs, scapulae, coracoids (~38 mm), furcula and humeri (Nesbitt et al., 2009)
(YFGP-yb2; holotype of Jeholornis curvipes) incomplete skull, mandible, six cervical vertebrae, eight dorsal vertebrae, twelve dorsal ribs, ?uncinate process, ?gastralia, synsacrum, nine caudal vertebrae, chevrons, scapulae (73 mm), incomplete coracoids, furcula, incomplete sternum, humeri (102 mm), radii, ulnae (one incomplete; 108 mm), pisiform, metacarpal I (10 mm), phalanx I-1 (34 mm), manual ungual I (14 mm), carpometacarpus (mcII 59, mcIII 55 mm), phalanx II-1 (26 mm), phalanx II-2, manual ungual II, partial phalanx III-1, partial phalanx III-2, manual ungual III, incomplete ilium, pubes (one partial; 74 mm), incomplete ischium, femora (76 mm), tibiotarsi (one incomplete; 94 mm), fibulae, metatarsal I, phalanx I-1, pedal ungual I, tarsometatarsi (one partial; 48 mm), phalanx II-1, phalanx II-2 (14 mm), pedal ungual II (~18 mm), phalanx III-1 (15.5 mm), phalanx III-2 (13 mm), phalanx III-3 (13 mm), pedal ungual III (15 mm), phalanx IV-1, phalanx IV-2, phalanx IV-3 (8 mm), phalanx IV-4 (10 mm), pedal ungual IV (11 mm), metatarsal V (Lefevre et al., 2014)
Early Albian, Early Cretaceous
Lingyuan, Jiufotang Formation, Liaoning, China
(AGB-6997; holotype of Kompsornis longicaudus) (adult) skull (80 mm), hyoid, mandibles, cervical vertebrae, first to thirteenth dorsal vertebrae, six partial dorsal ribs, synsacrum, first to twenty-seventh caudal vertebrae, chevrons, proximal scapulae, coracoids (42 mm), furcula, sternum (45 mm), three sternal ribs, humeri (119 mm), radii (111 mm), ulnae (116 mm), scapholunare, semilunate carpals, metacarpals I (13 mm), phalanges I-1 (33 mm), manual unguals I (17 mm), metacarpals II (63 mm), phalanges II-1 (28 mm), phalanges II-2 (25 mm), manual unguals II (16 mm), metacarpals III (56 mm), phalanges III-1 (13 mm), phalanges III-2 (7 mm), phalanges III-3 (14 mm), manual unguals III (9 mm), manual claw sheaths, ilia (58 mm), pubes (75 mm), ischia (26 mm), femora (79 mm), tibiae (81 mm), fibulae, metatarsals I (8 mm), phalanges I-1 (13 mm), pedal unguals I (11 mm), tarsometatarsi (mtII 40, mtIII 46, mtIV 43 mm), phalanges II-1 (12 mm), phalanges II-2 (16 mm), pedal unguals II (15 mm), phalanges III-1 (15 mm), phalanges III-2 (14 mm), phalanges III-3 (13 mm), pedal unguals III (12 mm), phalanges IV-1 (11 mm), phalanges IV-2 (8 mm), phalanges IV-3 (6 mm), phalanges IV-4 (11 mm), pedal unguals IV (9 mm), pedal claw sheaths, metatarsal V (Wang, Huang, Kundr�t, Cau, Liu, Wang and Ju, 2020)
Diagnosis- (after Ji et al., 2002) premaxillae toothless (also in Shenzhouraptor, Yandangornis, Zhongjianornis and Confuciusornithidae); maxilla toothless (?) (also in Yandangornis, Zhongjianornis and Confuciusornithidae); dentary toothless (?) (also in Omnivoropterygidae, Zhongjianornis and Confuciusornithidae); keeled sternum (also in some Confuciusornis).
(proposed) posteriorly forked dentary (also in Confuciusornithidae); dorsal parapophyses centrally placed(?); gastralia absent (maybe in Zhongjianornis); some proximal chevrons fused to centra(?); procoracoid process; low interclavicular angle (50-60 degrees); middle of furcular rami expanded.
Other diagnoses- Ji et al. list twenty-seven caudals as being an apomorphic number, but Shenzhouraptor can have that many too (IVPP 13550). U-shaped furculae are found in most basal paravians. The ulnohumeral ratio is not lower than  Shenzhouraptor (96-106% vs. 99-105%). An elongate forelimb is plesiomorphic for basal avialans, and is of equal length to Shenzhouraptor (forelimb/hindlimb ratio 123-134% vs. 122-133%). A lack of fibular-tarsal contact is also plesiomorphic for basal avialans. Metatarsal I is probably not retroverted based on AGB-6997, and the commonly artificially retroverted pedal unguals I of basal birds without the twisted metatarsal I.
Wang et al. (2020) claim the medial coracoid margin is concave unlike Shenzhouraptor, but that of the type is convex.  They write the coracoid lacks a fenestra unlike Shenzhouraptor, but it actually has a large fenestra (CAGS coll.; AGB-6997; visible in the holotype in Chiappe and Meng, 2016; YFGP-yb2 broken just distal to fenestra).  The humerofemoral ratio is not higher in Jixiangornis (134-156%) than Shenzhouraptor (140-147%).  Contra Wang et al., metatarsal V is present (YFGP-yb2, AGB-6997), hidden in the holotype which has feet preserrved in dorsal view. 
Comments- The description of Jixiangornis has only recently been translated from Chinese, but the holotype is well figured by Chiappe and Wang (2016). The skull, pectoral area, manus and pes were illustrated quite schematically in its original description. The matrices of Yuan (2005), O'Connor and Zhou (2012) and Turner et al. (2012) provide much needed information. Nesbitt et al. (2009) included a good quality photograph of the pectoral area for their theropod furcula paper, as well as a description of the furcula. Confusingly, this photo does not correspond to the holotype, though it is labeled as such. Differences include the disarticulation of one humerus, angle of the other, the fact the cervical series angles to the right, the furcula with an apex pointing anteriorly, the scapula on the right being oriented transversely, and the coracoids being nearly parallel. Yet the furcular morphology is identical, featuring the low interclavicular angle and expanded rami characteristic of the taxon. This therefore must be a referred specimen and as shown by a photo in Turner et al. (2012), is the undescribed CAGS specimen referred to in that publication.
The skull of the holotype is crushed with some questionable identifications. Two fenestrae are identified by Ji et al. as the external naris, with a third elongate fenestra existing posteroventral to these. It is likely the premaxillary and nasal processes disarticulated and deformed to cause this illusion. As illustrated, the orbit is very small and dorsally placed, with a large posterior antorbital fenestra placed almost entirely ventral to it, and even extending posteriorly under part of the orbit. This is quite unlike any theropod and is near certainly a misinterpretation. More likely, the supposed posterior antorbital fenestra is the anteroventral portion of the orbit, and the anterior antorbital fenestra is the real antorbital fenestra. This would make the lacrimal be the thinner portion anteroventral to its label, while the labeled jugal is probably a braincase or palatal element. The more vertical process ventral to the labeled jugal may then be the actual jugal.
Ji et al. (2002) believed Jixiangornis was closer to modern birds than Archaeopteryx and Shenzhouraptor, but outside Pygostylia. Yuan (2005) found Jixiangornis emerged sister to Rahonavis, closer to modern birds than archaeopterygids, but further than Shenzhouraptor. O'Connor and Zhou (2012) found it in a polytomy with Shenzhouraptor and Rahonavis, while Turner et al. (2012) found it closer to Aves than Shenzhouraptor and Sapeornis, but outside Pygostylia.
Initially, Wang et al. (2012 unpublished) used YFGP-yb2 to support synonymization of Jixiangornis and Jeholornis/Shenzhouraptor, though the manuscript was severely flawed and released early. The specimen was later found to have been modified, with a manus and pes being artificial. The resulting publication by Lefevre et al. (2014) named it as the new species Jeholornis curvipes, but I believe it is a junior synonym of Jixiangornis orientalis. Details to follow.
Synonymous with Shenzhouraptor?- Zhou and Zhang (2006) synonymized Jixiangornis with Jeholornis and Shenzhouraptor, merely stating it "possesses no obvious difference". Li et al. (2010) elaborated, noting both have long tails of more than 20 vertebrae (symplesiomorphic), similar forelimb/hindlimb ratios and well developed deltopectoral crests (also in Sapeornis and confuciusornithids). Known specimens of Jixiangornis are 12-30% larger than most Shenzhouraptor specimens, but only 92% the size of the largest, the Jeholornis holotype. Thus variation may be ontogenetic depending on the specimens being compared. Wang et al. (2012 unpublished) proposed the genera were synonymous based on a highly flawed manuscript which was later published in a form supporting generic separation (Lefevre et al., 2014).
"Luckyraptor"- Zhang (2007) featured an entry for Luckyraptor eastensis in his extensive book on Chinese fossils, but the specimen photograph showing CDPC-02-04-001 reveals this is merely a bad translation of Jixiangornis orientalis ("auspicious bird from the East").  While the absence of gen. et sp. nov. indicates it was not intended as a new taxon and is thus more similar to a misspelling that aren't given entries on this site, "Luckyraptor" was listed as a nomen nudum in Olshevsky's influential Dinosaur Genera List so has been spread widely online and the -raptor vs. -ornis difference means it is not a complete translation of Jixiangornis.  Besides not being indicated as an explicitly new name (ICZN Article 16.1), the lack of an "explicit fixation of a holotype, or syntypes" (Article 16.4.1) also makes "Luckyraptor eastensis" a nomen nudum regardless of the name's origin.
Kompsornis- Wang et al. (2020) described nearly complete skeleton AGB-6997 as a new taxon of jeholornithid Kompsornis longicaudus.  Among the supposedly diagnostic characters, the "distinctly angular antero-lateral corner of the sternum" is also present in the Jeholornis type and Jixiangornis (CAGS coll.), the former of which Wang et al. illustrated backwards, also explaining the higher anteromedian angle labeled in their figure.  The "stout postero-lateral processes fused to the sternum" is also seen in STM 2-5, cannot be compared in any Jixiangornis specimen, and may be taphonomic in the Jeholornis type as the posterolateral sternal margin is irregular so perhaps broken.  In any case, the supposed elongate posterolateral sternal process of that specimen has since been identified as a sternal rib.  A "large fenestra in the coracoid which is immediately proximal to the acrocoracoid and distinct from the dorsal margin by a bony strut narrower than the fenestra" is also found in Jixiangornis (CAGS coll.).  The fused pelvis cannot be compared with other Jixiangornis specimens except perhaps the disarticulated proximal left pubis of the holotype, which could also be broken due to taphonomy or ontogenetically unfused being ~91% the size of the Kompsornis type.  The pubis is not more posteriorly inclined than Jixiangornis (YFGP-yb2), with identical angles between the proximal portion and line drawn between the dorsal acetabular edge and ventral preacetabular edge.  Finally the tenth to twenty-third caudal centra are said to be more elongate ("more than five times as long as they are dorso-ventrally tall" versus a ratio of 3-4 times), but this does not seem to be the case when compared to the Jeholornis and Jixiangornis types, each of which has a similar ratio of at least five times.  The diagnosis lists long tail and forelimb/hindlimb ratios, but the tail is similar in length to Jixiangornis' type (578 vs. 573% of femoral length) although the forelimb is longer (145%) than other Jixiangornis (123-134%) or Shenzhouraptor (122-133%) specimens.  Notably, the tibia is supposedly shorter than other jeholornithids (103% of femoral length vs. 116-132%).  Suspiciously, the proximal end of each femur and distal end of each tibia is hidden beneath the sacrum and pelvis, which given the range of error allowed by covered portions could bring both ratios into line with other specimens.  The sternum is also fused in the Jixiangornis type and probably YFGP-yb2.  The fifth metatarsal was stated to be absent, but appears to be present on the right pes passing distomedially ventral to the base of metatarsal IV.  The final character is the diagnosis is "ungual of the second pedal digit largest and much more expanded proximally than other pedal unguals" which is also true in the Jixiangornis type. Additional supposed differences from Jixiangornis are- well developed lateral coracoid process in Jixiangornis' type (but not in CAGS coll. or YFGP-yb2); straighter humeral shaft in Jixiangornis (as in the right humerus of Kompsornis; the left humerus is more sigmoid but also exposed in medial view); retroverted hallux in Jixiangornis (but this can only be determined via metatarsal I torsion, not which way the hallucial unguals happen to point when taphonomically flattened; and the Jixiangornis type's metatarsals I are too poorly preserved).
Examining the specimen for characters distinguishing Shenzhouraptor and Jixiangornis, it has the posteriorly forked dentary, low interclavicular angle, furcular arms expanded in the middle, keeled sternum and procoracoid process of Jixiangornis, while lacking the lacrimal fossae and anterdorsally angled dorsal jugal process of Shenzhouraptor (identified as the quadratojugal by Wang et al., but would be unusually robust if so).  Kompsornis was stated to differ from Jixiangornis in having a less constricted furcular median (which is true compared to the holotype and CAGS coll.) and shorter pedal unguals compared to penultimate phalanx length (true for the holotype, but comparable to YFGP-yb2).  The only anomaly is that the Kompsornis type is listed as being from the "Jiufotang Formation, Lingyuan locality", while other Jixiangornis specimens have been from the Yixian Formation.
References- Ji, Ji, Zhang, You, Zhang, Wang, Yuan and Ji, 2002. A new avialian bird - Jixiangornis orientalis gen. et sp. nov. - from the Lower Cretaceous of Western Liaoning, NE China. Journal of Nanjing University (Natural Sciences). 38(6), 723-736.
Yuan, 2005. Restudy on sapeornithids from the Lower Cretaceous of Yixian County, Liaoning. PhD Thesis. China University of Geosciences. 157 pp.
Zhou and Zhang, 2006. Mesozoic birds of China- A synoptic review. Vertebrata PalAsiatica. 44(1), 74-98.
Zhang, 2007. The Fossils of China. China University of Geosciences Press. 502 pp.
Turner, 2008. Phylogenetic relationships of paravian Theropods. PhD Thesis. Columbia University. 666 pp.
Nesbitt, Turner, Spaulding, Conrad and Norell, 2009. The theropod furcula. Journal of Morphology. 270, 856-879.
Li, Sullivan, Zhou and Zhang, 2010. Basal birds from China: A brief review. Chinese Birds. 1(2), 83-96.
O'Connor and Zhou, 2012. A redescription of Chaoyangia beishanensis (Aves) and a comprehensive phylogeny of Mesozoic birds. Journal of Systematic Palaeontology. iFirst 2012, 1-18.
Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 1-206.
Wang, Dyke and Godefroit, 2012 unpublished. A new specimen of a Jeholornis-like long-tailed bird shows that Jixiangornis is a junior synonym of Jeholornis prima. Acta Paleontologica Polonica. MS.
Lefevre, Hu, Escuillie, Dyke and Godefroit, 2014. A new long-tailed basal bird from the Lower Cretaceous of North-eastern China. Biological Journal of the Linnean Society. 113, 790-804.
Chiappe and Wang, 2016. Birds of Stone: Chinese Avian Fossils from the Age of Dinosaurs. Johns Hopkins University Press. 188 pp.
Wang, Huang, Kundr�t, Cau, Liu, Wang and Ju, 2020. A new jeholornithiform exhibits the earliest appearance of the fused sternum and pelvis in the evolution of avialan dinosaurs. Journal of Asian Earth Sciences. 199, 104401.

Yandangithformes Cai and Zhao, 1999
Yandangornithidae Cai and Zhao, 1999 emmend. Creisler, unpublished
= Yandangithidae Cai and Zhao, 1999
Comments- Cai and Zhao (1999) incorrectly formed both order and family names for Yandangornis. Creisler (DML, 2000) noted that the ICZN requires the family name to be emmended, as it was named in 1999 and thus falls under the jurisdiction of the 3rd edition (the 4th edition changed this rule). Order names are not covered by the ICZN though, so Yandangithformes must remain. Both names are presently redundant with Yandangornis, but may prove useful if Dalianraptor, Jixiangornis, Shenzhouraptor or another taxon is found to be more closely related to Yandangornis than to Aves.
References- Cai and Zhao, 1999. A long tailed bird from the Late Cretaceous of Zhejiang. Science in China (series D). 42(4), 434-441.
Creisler, DML 2000. https://web.archive.org/web/20190416181247/http://dml.cmnh.org/2000Jul/msg00451.html
Yandangornis Cai and Zhao, 1999
Y. longicaudus Cai and Zhao, 1999
Early Campanian, Late Cretaceous
Tangshang Group, Zhejiang, China
Holotype- (Zhejiang Museum of Natural History M1326) (588 mm) skull (47 mm), mandibles (35 mm), nine cervical vertebrae (80 mm; fifth 9.2 mm, ninth 11 mm), four dorsal vertebrae, dorsal ribs, gastralia, nineteen caudal vertebrae (305 mm), distal scapula, partial coracoid, partial furcula, sternum (50 mm), humeri (80 mm), proximal radii, proximal ulnae, distal phalanx II-1, phalanx II-2, manual ungual II, distal phalanx III-2, phalanx III-3, manual ungual III, pubis (41 mm), femora (106 mm), tibiotarsi (132 mm), fibula (40 mm), metatarsal I, phalanx I-1 (7.8 mm), pedal ungual I (4.2 mm), tarsometatarsi (70 mm), phalanges II-1, phalanges II-2, pedal unguals II (7.2 mm), phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III (7 mm), phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV
Diagnosis- (after Cai and Zhao, 1999) premaxillae toothless (also in Shenzhouraptor, Jixiangornis, Zhongjianornis and Confuciusornithidae); sternum much longer than wide; metatarsus fused distally; pedal unguals reduced in size and curvature.
(proposed) very large premaxillae (ventral edge equals 40% of skull length); mandible less than three-fourths skull length; last cervical vertebra longer than others; sternum with broad median ventral convexity on posterior half; sternum concave posteriorly; distal femoral condyles more than twice as wide as shaft; phalanx III-1 shortest in third pedal digit.
Other diagnoses- Cai and Zhao (1999) include several other characters in their diagnosis which are symplesiomorphies (lightly built skull; gastralia present; unreduced forelimbs; humerus lacking pneumatic fossa or foramen; broad sternum; sternum with lateral processes; long and slender digits). The number of caudal vertebrae is similar to Dalianraptor.
Comments- This specimen was discovered in 1986, associated with the pterosaur Zhejiangopterus. It was illustrated in a somewhat schematic manner, with only low quality photographs. The authors refer Yandangornis to its own family (Yandangithidae) and order (Yandangithiformes) within the Sauriurae. As the Sauriurae is based on symplesiomorphies, its relationships must be reconsidered. Very few authors have mentioned Yandangornis since. Paul (2002) considered the genus to be a neoflightless taxon more derived than Archaeopteryx but outside Avebrevicauda. Zhou and Zhang (2006) merely stated it showed "no diagnosis of birds" and questioned whether it was a bird-like dinosaur instead. However, numerous characters are shared with avialan birds including the reduced number of caudal vertebrae, fused sternum, trochanteric crest, completely fused tibiotarsus, fibula not contacting tarsus, fused metatarsus and proximal expansion of metatarsal III. Previously, Auditore (DML, 2002) reported personal communication from Zhou indicating he believed Yandangornis is synonymous with Shenzhouraptor (= Jeholornis), but this is highly unlikely given the numerous differences and later age of Yandangornis.
Description- The skull is preserved in ventral view, with the mandibles articulated. It is elongate with a pointed anterior tip and subparallel lateral edges. The premaxillae are toothless and large, even more extensive than confuciusornithids. A broad premaxillary palatal shelf seems to be present. The maxillae are also toothless and show a large antorbital fenestra. Other preserved elements include jugals, quadrates, pterygoids and the basisphenoid, although no details are discernable. The articulated (fused?) dentaries form an acute angle and end 7 mm behind the rostral premaxillary tip. The retroarticular process appears short.
The nine cervical vertebrae are amphicoelous and seem to lack ribs, probably due to poor preservation or illustration. They lengthen posteriorly from three to eleven millimeters. The fifth is 9.2 mm long and 6.1 mm wide, while the ninth is 11 mm long and 7.2 mm wide. No details are visible regarding the preserved dorsal vertebrae (two mid-dorsals, two posterior dorsals). Dorsal ribs and gastralia are also preserved. Nineteen caudal vertebrae are preserved, with at least one missing at the tip. The centra are amphicoelous and the first five have transverse processes. Vertebrae become very slender after the fifth. There are no dromaeosaur-like elongate prezygopophyses and no pygostyle. No chevrons are preserved and are claimed to have been originally absent, though this seems implausible.
The coracoid is preserved articulated to the sternum anteriorly and is described as being "similar to other Mesozoic birds, especially the Cretaceous birds". This could suggest it was strut-like, but the figure is unclear regarding this point. The distal scapula is said to be elongate and straight. A furcular fragment is preserved, possibly the left distal end. The sternum is fused and twice as long as wide, as in derived euornithines. There are anterolateral processes, short tapered posterolateral processes, no posteromedial processes, but a short tapered posteromedian process is present. It lacks a keel, but has a median bump in the posterior half. What are illustrated as three elongate sternal ribs on either side of the sternum are more likely dorsal ribs based on their length.
The humerus is sigmoidal, with a low proximally placed deltopectoral crest and no pneumatic fossa. The distal condyles are distinct and a shallow olecranal fossa is present on the ulnar condyle. The radius is 4 mm wide, while the bowed ulna is 6 mm wide. There is a slight olecranon process. The phalanges are slender, with digit III reaching to the tip of II-2. Manual unguals are reduced.
The pubes are preserved in an opisthopubic position and taper distally in anterior view. They were not fused to the other pelvic elements. The authors state the pubis lacks an "anterior process", perhaps the anterior boot?
The femur is slender and straight, with a trochanteric crest and horizontal or slightly inclined head. There is a slight neck and no fourth trochantor or posterior trochantor. The distal end is greatly expanded. The tibia is fused to the astragalus and calcaneum. No fibular crest is visible, and the distal end is expanded more than the proximal end. The fibula is only 30% of the tibial length. The tarsometatarsus is non-arctometatarsalian, with the proximal end of metatarsal III actually wider than the distal end. Fusion is extensive, but incomplete in the distal tenth. It is elongate and slender. Metatarsal II is more robust than metatarsal IV, and is slightly shorter. Proximally, the tarsometatarsus has two shallow cotylae. Digit I is set 20% up the shaft of metatarsal II and is not preserved in a reversed orientation. The ungual, like the others, is small and almost straight. The ungual on digit II is slightly longer than the others. Digit II is not modified for predatory use in any way and is 14.8 mm without its ungual, while digit III is 30 mm without its ungual. Phalanx II-1 is much shorter than III-1, like most paravians. Phalanx II-2 is longer than II-1, as in some eumaniraptorans.
References- Cai and Zhao, 1999. A long tailed bird from the Late Cretaceous of Zhejiang. Science in China (series D). 42(4), 434-441.
Paul, 2002. Dinosaurs of the Air. The Johns Hopkins University Press, Baltimore. 460 pp.
Auditore, DML 2004. https://web.archive.org/web/20190416181246/http://dml.cmnh.org/2004Oct/msg00268.html
Zhou and Zhang, 2006. Mesozoic birds of China - A synoptic review. Vertebrata PalAsiatica. 44(1), 74-98.

Zhongjianornis Zhou, Zhang and Li, 2010
= "Zhongjianornis" Zhou, Zhang and Li, 2009 online
Z. yangi Zhou, Zhang and Li, 2010
= "Zhongjianornis yangi" Zhou, Zhang and Li, 2009 online
Early Albian, Early Cretaceous
Jiufotang Formation, Liaoning, China
Holotype- (IVPP V15900) (570 g, adult) skull (61 mm), mandibles, hyoids, six cervical vertebrae, seven dorsal vertebrae, partial dorsal ribs, three uncinate processes, partial synsacrum (~28 mm), eight caudal vertebrae, chevron, scapulae (59 mm), coracoids (36 mm), partial furcula, sternal plate, humeri (71 mm), radii (~73 mm), ulnae (74 mm), pisiforms, metacarpals I (8 mm), phalanges I-1 (15 mm), manual unguals I, carpometacarpi (34 mm; mcII 31 mm), phalanges II-1 (18 mm), phalanges II-2 (19.5 mm), manual unguals II, phalanx III-1, ilia (39 mm), incomplete pubes, ischium, femora (46.5, 48 mm), tibiotarsi (~65, 71 mm), fibula (53 mm), metatarsal I (6 mm), phalanges I-1 (5 mm), pedal unguals I, tarsometatarsi (~29 mm; mtII 26, mtIII ~28, mtIV ~29 mm), phalanges II-1 (6.5 mm), phalanges II-2 (8 mm), pedal unguals II (11 mm), phalanges III-1 (6.5 mm), phalanges III-2 (~7 mm), phalanges III-3 (~7 mm), pedal unguals III (12 mm), phalanges IV-1 (7 mm), phalanges IV-2 (5 mm), phalanges IV-3 (~4 mm), phalanges IV-4 (6.5 mm), pedal unguals IV, feathers
Diagnosis- (after Zhou et al., 2010) sharply pointed premaxilla (also in Confuciusornithidae); premaxillae toothless (also in Shenzhouraptor, Jixiangornis, Yandangornis and Confuciusornithidae); maxilla toothless (also in Shenzhouraptor, Jixiangornis, Yandangornis and Confuciusornithidae); dentary toothless (also in Omnivoropterygidae, Zhongjianornis and Confuciusornithidae); manual ungual I small and weakly curved; metatarsal IV longer than metatarsal III.
(proposed) enlarged premaxilla; dorsal maxillary process absent; mandible sigmoidal such that dentary is dorsally convex and surangular is dorsally concave (also in some Sapeornis specimens); caudal centra procoelous (also in Confuciusornis zhengi); caudal zygapophyses non-contacting; proximal and distal humeral ends not twisted; moderately developed humeral bicipital crest (also in Archaeopteryx and Sapeornis); distal humerus highly compressed anteroposteriorly (also in Jixiangornis); dorsal ulnar cotyla not convex; dorsal ulnar condyle semilunate (also in Anchiornis and Confuciusornis zhengi); dorsal trochlear surface of ulnar dorsal condyle extends proximally an amount equal to its width; manual digit I reduced to extend to end of metacarpal II (also in Jixiangornis); metacarpal III extends distally past II (also in scansoriopterygids and some Shenzhouraptor specimens); ilial postacetabular process not less than half as deep as preacetabular process (also in Anchiornis); posterolateral ridge on femur extending proximally from lateral condyle; ginglymoid metatarsal II (also in Scansoriopteryx); metatarsal II trochlea much wider than III or IV; metatarsal IV reduced in width (also in Archaeopteryx); metatarsal V absent (also in Zhongornis?).
Other diagnoses- Zhou et al. (2010) included several other characters in their diagnosis. The tall deltopectoral crest (270% of shaft width) is also found in omnivoropterygids and confuciusornithids. The length of the crest varies strongly between humeri (36-44% of humeral length), is overlapped by Shenzhouraptor and confuciusornithids and closely approached by other basal avialans. Manual ungual II is equally small in Dalianraptor, Yandangornis and confuciusornithids, while manual ungual III is unknown (if present), leaving only the size of manual ungual I to be diagnostic.
Comments- The description of Zhongjianornis was originally released online July 2009, but not officially published until January 2010.
Zhou et al. (2010) included Zhongjianornis in a version of Clarke's matrix and found it to be outside Pygostylia, but more closely related to it than Sapeornis or Shenzhouraptor. In my analyses it has an unstable position within Euavialae, but is generally not in Avebrevicauda.
Reference- Zhou, Zhang and Li, 2010. A new Lower Cretaceous bird from China and tooth reduction in early avian evolution. Proceedings of the Royal Society B. 277(1679), 219-227.

Avebrevicauda Paul, 2002
Definition- (ten or fewer free caudals homologous with Passer domesticus) (modified from Paul, 2002)
Other definitions- (Passer domesticus <- Jeholornis prima, Rahonavis ostromi) (modified from Agnolin and Novas, 2013)
= Pygostylia sensu Gauthier and de Queiroz, 2001
Definition- (fused distal caudal vertebrae homologous with Vultur gryphus)

undescribed avebrevicaudan (Sanz, Chiappe, Fernadez-Jalvo, Ortega, Sanchez-Chillon, Poyato-Ariza and Perez-Moreno, 2001)
Late Barremian, Early Cretaceous
Calizas de La Huerguina Formation, Spain
Material- (LH 11386 bird 2) (juvenile) sacrum, seven caudal vertebrae, pygostyle, incomplete ilium, femora (one distal), tibia, astragalus, metatarsal II, metatarsal III, phalanx III-1, phalanges III-2, phalanges III-3, pedal ungual III, metatarsal IV, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV
Comments- This specimen is the second most complete of four juvenile birds found associated in a theropod or pterosaur pellet. It was only identified as a bird by Sanz et al. (2001), and colored light gray in their illustration. The pygostyle indicates this is an avebrevicaudan, while the length of the pygostyle (over twelve centra long) excludes euornithines from consideration. The medial tibiotarsal condyle being wider than the lateral one is only seen in Patagopteryx among euornithines. Also, the proximal end of metatarsal III is in the same plane as metatarsals II and IV, which is only seen in Patagopteryx, Archaeorhynchus and Hongshanornis among euornithines. Yet the metatarsus is unlike enantiornithines in having an unreduced metatarsal IV, though this is present in some juveniles such as GMV-2158. It is also unlike most enantiornithines in having metatarsal II's trochlea be wider than III's, though longipterygids, Vorona and Liaoningornis are exceptions. The pubic peduncle is not transversely compressed as occurs in longipterygids though. This may be a non-ornithothoracine avebrevicaudan, or perhaps a juvenile liaoningornithid.
Reference- Sanz, Chiappe, Fernadez-Jalvo, Ortega, Sanchez-Chillon, Poyato-Ariza and Perez-Moreno, 2001. An Early Cretaceous pellet. Nature. 409, 998-999.

Jinguofortisidae Wang, Stidham and Zhou, 2018
Definition- (after Wang, Stidham and Zhou, 2018) (Jinguofortis perplexus, Chongmingia zhengi <- Sapeornis chaoyangensis, Confuciusornis sanctus)
Diagnosis- (after Wang, Stidham and Zhou, 2018) scapula and coracoid fused; boomerang-shaped furcula without hypocleidium; proximal margin of humerus concave centrally; deltopectoral crest large and not perforated; manual digit I terminating at the distal end of metacarpal II; manual phalanx II-1 longer than phalanx II-2; metacarpal III markedly bowed laterally.
Comments- Wang et al. (2018) created this family for the pairing of Chongmingia and their new genus Jinguofortis.  An ornithothoracine should be added as an external specifier in the definition, in case Jinguofortis is closer to Passer than Sapeornis or Confuciusornis.
Reference- Wang, Stidham and Zhou, 2018. A new clade of basal Early Cretaceous pygostylian birds and developmental plasticity of the avian shoulder girdle. Proceedings of the National Academy of Sciences. 115(42), 10708-1071.

Jinguofortis Wang, Stidham and Zhou, 2018
J. perplexus Wang, Stidham and Zhou, 2018
Barremian, Early Cretaceous
Shixia, Dabeigou Formation, Hebei, China
Holotype- (IVPP V24194) (250 g; adult) incomplete skull, incomplete mandibles, eight cervical vertebrae, nine dorsal vertebrae, dorsal ribs, gastralia, synsacrum (25.67 mm), four caudal vertebrae, two chevrons, pygostyle (~23.89 mm), furcula, incomplete sternum, scapulocoracoids (scapula 51.45 mm), humeri (66.64 mm), radii (65.96 mm), ulnae (68.25 mm), scapholunares, carpometacarpi (28.89 mm, mcI 7.98 mm), phalanges I-1 (16.42 mm), manual ungual I (4.94 mm), phalanges II-1 (17.14 mm), phalanges II-2 (13.91 mm), manual unguals II (3.52 mm), phalanges III-1 (4.04 mm), phalanx III-2 (1.31 mm), manual claw sheaths,  ilium (36.82 mm), pubes (46.34 mm), ischium (21.54 mm), femora (52.58 mm), tibiae (58.56 mm), metatarsals I, phalanges I-1 (9.34 mm), pedal unguals I (7.79 mm), tarsometatarsi (30.85 mm), phalanges II-1 (7.46 mm), phalanges II-2 (9.26 mm), pedal unguals II (6.42 mm), phalanges III-1 (9.78 mm), phalanges III-2 (8.50 mm), phalanges III-3 (9.01 mm), phalanges IV-1 (6.73 mm), phalanges IV-2 (4.96 mm), phalanges IV-3 (4.56 mm), phalanges IV-4 (5.91 mm), pedal unguals IV (4.14 mm), body feathers, remiges, retrices, gastroliths
Diagnosis- (after Wang et al., 2018) premaxillae toothed anteriorly; 9-10 dorsal vertebrae; boomerang-shaped furcula with interclavicular angle of 70 degrees; postacetabular process tapers rapidly to a point; elongate hallux about 70% as long as pedal digit II.
Comments- This was discovered around March 2017.
Wang et al. (2018) added this to O'Connor's avialan analysis and recovered it sister to Chongmingia, with the pair being sister to Sapeornis plus Ornithothoraces.
Reference- Wang, Stidham and Zhou, 2018. A new clade of basal Early Cretaceous pygostylian birds and developmental plasticity of the avian shoulder girdle. Proceedings of the National Academy of Sciences. 115(42), 10708-1071.

Chongmingia Wang, Wang, Wang and Zhou, 2016
C. zhengi Wang, Wang, Wang and Zhou, 2016
Early Albian, Early Cretaceous
Dapingfang, Jiufotang Formation, Liaoning, China
Holotype- (STM 9-9) (adult) cervical vertebra, dorsal vertebra, presacral vertebral fragments, partial dorsal ribs, gastralia, synsacrum, two caudal vertebrae, incomplete scapulocoracoid (scapula 44.6 mm), furcula, humeri (72.6 mm), radii (74.2 mm), ulnae (77.8 mm), scapholunare, pisiforms, carpometacarpi (mcI 9.6, mcII 30.4 mm; one incomplete), phalanx I-1 (17 mm), phalanx II-1 (18.9 mm), phalanx II-2 (15.7 mm), manual ungual, incomplete pubes, femora (61.6 mm), tibiotarsi (69.4 mm), fibula (54.1 mm), metatarsal I, phalanx I-1 (9.5 mm), pedal ungual I, tarsometatarsi (mtII 33.3, mtIII 37.3, mtIV 35.6 mm), phalanx II-1 (11.5 mm), phalanx II-2 (12.1 mm), pedal unguals II (10.9 mm), phalanx III-1 (11.2 mm), phalanx III-2 (9.6 mm), phalanx III-3 (9.5 mm), pedal ungual III (9.3 mm), phalanges IV-1 (7.3 mm), phalanges IV-2 (5.4 mm), phalanges IV-3 (4.8 mm), phalanges IV-4 (5.7 mm), pedal unguals IV (7.6 mm), seven pedal phalanges, pedal ungual, metatarsal V (4.1 mm), body feathers, remiges
Diagnosis- (after Wang et al., 2016) furcula boomerang-shaped and robust; interclavicular angle of 68 degrees; coracoid and scapula fused; proximal margin of humerus concave centrally; humerus bears expanded deltopectoral crest; metacarpal I long relative to length of carpometacarpus, with ratio of 0.32; metacarpal III strongly bowed laterally; proximal tarsals fused to tibia; forelimb short relative to hindlimb (length ratio 1.07); pedal digit II longer than IV.
Comments- Wang et al. (2016) found Chongmingia to be sister Ornithothoraces (using Cau's matrix) or sister to Shenzhouraptor+Pygostylia (using O'Connor's matrix).
Reference- Wang, Wang, Wang and Zhou, 2016. A new basal bird from China with implications for morphological diversity in early birds. Scientific Reports. 6, 19700.

Cratonavis Li, Wang, Stidham and Zhou, 2023
C. zhui Li, Wang, Stidham and Zhou, 2023
Early Albian, Early Cretaceous
Xiaotaizi, Jiufotang Formation, Liaoning, China
Holotype- (IVPP V31106) (666 g; adult) skull, mandibles, hyoid, nine cervical vertebrae, nine dorsal vertebrae, dorsal ribs, uncinate processes, gastralia, synsacrum (29.64 mm), eight caudal vertebrae, pygostyle (17.77 mm), scapulocoracoids (scap 62.66 mm), furcula, sternum, humeri (61.86 mm), radii (67.61 mm), ulnae (73.40 mm), scapholunares, pisiforms, carpometacarpi (28.71 mm, mcI 8.41 mm), phalanges I-1 (16.07 mm), manual unguals I (5.69 mm), phalanges II-1 (17.39 mm), phalanges II-2 (12.11 mm), manual unguals II (3.16 mm), phalanges III-1 (5.1 mm), ilia (33.73 mm), pubes (~53.53 mm), ischia (~26.66 mm), femora (50.80 mm), tibiotarsi (56.42 mm), fibulae, metatarsals I (15.71 mm), phalanges I-1 (11.12 mm), pedal unguals I (8.11 mm), tarsometatarsi (28.20 mm), phalanges II-1 (8.15 mm), phalanges II-2 (10.43 mm), pedal unguals II (6.45 mm), phalanges III-1 (9.50 mm), phalanges III-2 (8.47 mm), phalanges III-3 (8.74 mm), pedal unguals III (7.39 mm), phalanges IV-1 (6.71 mm), phalanges IV-2 (5.51 mm), phalanges IV-3 (5.37 mm), phalanges IV-4 (5.99 mm), pedal unguals IV (6.35 mm), pedal claw sheaths, metatarsal V, body feathers, remiges
Diagnosis- (after Li et al., 2023) ascending process of the maxilla perforated only by maxillary fenestra; maxillary fenestra longer anteroposteriorly than dorsoventrally; ventral ramus of lacrimal with lateral flange; dorsal process of quadratojugal much longer (3x) than anterior process; pterygoid with posteroodorsally directed quadrate ramus; prominent retroarticular process; dorsal centra laterally excavated by broad fossae; scapula longer than humerus; posterior end of postacetabular process dorsally deflected; metatarsal I ~60% of tarsometatarsal length; hallux with longest non-ungual and ungual pedal phalanges.
Comments- Li et al. (2023) recovered Cratonavis sister to Chongmingia in Jinguofortisidae using O'Connor's bird matrix. 
Reference- Li, Wang, Stidham and Zhou, 2023. Decoupling the skull and skeleton in a Cretaceous bird with unique appendicular morphologies. Nature Ecology & Evolution. 7, 20-31.

Omnivoropterygiformes Czerkas and Ji, 2002
Definition- (Omnivoropteryx sinousaorum <- Passer domesticus) (Martyniuk, 2012)
= Omnivoropterygidae Czerkas and Ji, 2002
= "Sapeornithidae" Yuan, 2005
= Sapeornithiformes Zhou and Zhang, 2006
= Sapeornithidae Zhou and Zhang, 2006
Comments- Czerkas and Ji (2002) erected Omnivoropterygidae as a monotypic family for Omnivoropteryx, though it has been basically ignored in the literature since. Yuan (2005) named Sapeornithidae in his unpublished thesis for Sapeornis and Didactylornis (with no mention of Omnivoropteryx), and the family was later published by Zhou and Zhang for Sapeornis alone (Didactylornis was unpublished, and Omnivoropteryx again ignored). Yet the ICZN states that Omnivoropterygidae must have priority if Sapeornis belongs to the same family as Omnivoropteryx, even if the latter is found to be a junior synonym of the former.
Both Omnivoropterygiformes and Sapeornithiformes were named as monotypic orders, so they are currently redundant with respect to Omnivoropterygidae. Yet Martyniuk (2012) defined Omnivoropterygiformes, making it the first defined name for this group.
References- Czerkas and Ji, 2002. A preliminary report on an omnivorous volant bird from Northeast China. Feathered Dinosaurs and the Origin of Flight. The Dinosaur Museum Journal. 1, 127-135.
Yuan, 2005. Restudy on sapeornithids from the Lower Cretaceous of Yixian County, Liaoning. PhD Thesis. China University of Geosciences. 157 pp.
Zhou and Zhang, 2006. Mesozoic birds of China- A synoptic review. Vertebrata PalAsiatica. 44(1), 74-98.
Martyniuk, 2012. A Field Guide to Mesozoic Birds and Other Winged Dinosaurs. Vernon, New Jersey. Pan Aves. 189 pp.

Falcatakely O'Connor, Turner, Groenke, Felice, Rogers, Krause and Rahantarisoa, 2020
F. forsterae O'Connor, Turner, Groenke, Felice, Rogers, Krause and Rahantarisoa, 2020
Middle Maastrichtian, Late Cretaceous
MAD 05-42, Anembalemba Member of Maevarano Formation, Madagascar
Holotype- (UA 10015; field number MAD 10539) incomplete skull (~85 mm), sclerotic plates
Middle Maastrichtian, Late Cretaceous
MAD 93-18, Anembalemba Member of Maevarano Formation, Madagascar
Referred- ?(FMNH PA 741) synsacrum (43 mm) (Forster and O'Connor, 2000; described by O'Connor and Forster, 2010)
Diagnosis- (after O'Connor et al., 2020) extended, high maxilla that forms the dorsal contour of the rostrum; dimpled texture on the nasal and lacrimal, particularly on the triangular posterodorsal process of the latter; lacrimal with posteriorly expanded ventral process; long, straight posterior process of the jugal.
Other diagnoses- Sapeornis also has an "antorbital fenestra nearly as long as tall" and a "large, flat jugal process of the postorbital"
Comments- The holotype skull was discovered on July 26 2010 and described by O'Connor et al. (2020).  The authors recovered it as an enantiornithine using Brusatte's TWiG matrix and O'Connor's avialan matrix.  Cau (online 2020) recovered it as a noasaurid or (if constrained as a coelurosaur, six steps longer) a basal dromaeosaurid.  Adding it to Hartman et al.'s maniraptoromorph matrix results in it being a therizinosaurid or sister taxon of Sapeornis (Mortimer, online 2020).  The latter is provisionally preferred based on the synsacrum FMNH PA 741 which was described as similar to Sapeornis, but it is likely that future discoveries of African small theropods will modify this.  Enforcing Falcatakely as an enantiornithine, noasaurid, Rahonavis or Vorona in the Hartman et al. analysis requires 6, 3, 1 and 7 more steps respectively.  While this makes synonymy with Rahonavis plausible on the surface, the dentary FMNH PA 740 referred to Rahonavis is quite different in its curvature and extensive tooth row (but similar to unenlagiines), and the two sacral morphotypes show two Maevarano maniraptorans coexisted at this size anyway.  The lack of equivalently sized ceratosaur or enantiornithine postcrania also make those options less likely.
Regarding FMNH PA 741, the seven sacrals are shared with Jixiangornis and Avebrevicauda, and O'Connor and Forster (2010) felt it resembled Sapeornis in having- broad sacral transverse processes with first three oriented anterolaterally, the fourth transversely in the fourth position, and the fifth through seventh posterolaterally; distal ends of fifth through seventh transverse processes united.
References- Forster and O'Connor, 2000. The avifauna of the Upper Cretaceous Maevarano Formation, Madagascar. Journal of Vertebrate Paleontology. 20(3), 41A-42A.
O'Connor and Forster, 2010. A Late Cretaceous (Maastrichtian) avifauna from the Maevarano Formation, Madagascar. Journal of Vertebrate Paleontology. 30(4), 1178-1201.
Cau, 2020 online. theropoda.blogspot.com/2020/11/falcatakely-eterodossia-e-pluralismo.html
Mortimer, online 2020. theropoddatabase.blogspot.com/2020/11/is-falcatakely-bird.html
O'Connor, Turner, Groenke, Felice, Rogers, Krause and Rahantarisoa, 2020. Late Cretaceous bird from Madagascar reveals unique development of beaks. Nature. 588, 272-276.

Sapeornis Zhou and Zhang, 2002
= Omnivoropteryx Czerkas and Ji, 2002
= "Didactylornis" Yuan, 2005
= Didactylornis Yuan, 2008
= Shenshiornis Hu, Li, Hou and Xu, 2010
S. chaoyangensis Zhou and Zhang, 2002
= Omnivoropteryx sinousaorum Czerkas and Ji, 2002
= "Didactylornis jii" Yuan, 2005
= Didactylornis jii Yuan, 2008
= Sapeornis angustis Provini, Zhou and Zhang, 2009
= Shenshiornis primita Hu, Li, Hou and Xu, 2010
Early Albian, Early Cretaceous
Jiufotang Formation, Liaoning, China
Holotype- (IVPP V12698) (900 g) four cervical vertebrae, ten dorsal vertebrae, seven dorsal ribs, gastralia, several caudal vertebrae, pygostyle (~25 mm), scapulae (~75, 75 mm), coracoids (~40 mm), furcula (43.1 mm), humeri (126.5, 129.6 mm), radii (133, 131.9 mm), ulnae (133.1, 135.1 mm), scapholunare, metacarpal I (14.3 mm), phalanges I-1 (33.6 mm), manual ungual I (~19.1 mm), carpometacarpi (II 57.1 mm, III 54.6 mm), phalanges II-1 (30, 32.2 mm), phalanges II-2 (27.7 mm), manual ungual II (~18 mm), phalanx III-1, phalanx III-2, ilia (~56 mm), pubes (85.4, 87 mm), ischia (42.1 mm), femur (80.4 mm), tibiotarsus (83.6 mm), fibula (~72.4 mm), distal tarsal, tarsometatarsus (44.6 mm), over eight pedal phalanges, pedal ungual, metatarsal V
Referred- ?(CAGS-02-IG-gausa-3/DM 609; holotype of Omnivoropteryx sinousaorum) (subadult) skull, mandible, two cervical vertebrae, ten dorsal vertebrae, dorsal ribs, sacrum, scapulae (one partial), proximal coracoid, humeri (one incomplete; 100 mm), ulnae (one partial; 96.5 mm), radius, phalanx I-1, manual ungual I, metacarpal II (46.5 mm), phalanx II-1, phalanx II-2, manual ungual II, metacarpal III, partial ilium, pubes (51 mm), femora (61 mm), tibiotarsi (one incomplete; 67 mm), fibula, metatarsals I, phalanges I-1, pedal unguals I, metatarsals II (one partial), phalanges II-1, phalanges II-2, pedal unguals II, metatarsals III (one partial; 35 mm), phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, metatarsals IV (one partial), phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV (Czerkas and Ji, 2002)
?(CAGS-03-07-08) incomplete skull (65 mm), partial mandibles, eleven cervical vertebrae, six or seven dorsal vertebrae, twelve pairs of dorsal ribs, gastralia, sacrum, caudal vertebrae, pygostyle (20 mm), scapulae (one partial; ~72 mm), coracoids (one partial; 33 mm), furcula, humeri (130 mm), radii (~124 mm), ulnae (~129 mm), metacarpals I (~12 mm), phalanges I-1 (30 mm), manual unguals I (12 mm straight, 21 mm on curve), carpometacarpi (II 58 mm, III 50 mm), phalanges II-1 (26 mm), phalanges II-2 (24 mm), manual unguals II (12 mm straight, 15 mm on curve), phalanges III-1 (~12 mm), phalanx III-2 (~6 mm), ilia (one partial; 42 mm), pubes (82 mm), partial ischia (23 mm), femora (~78 mm), tibiotarsi (~86 mm), partial fibulae, metatarsals I (11 mm), phalanges I-1 (15 mm), pedal unguals I (12 mm straight, 15 mm on curve), tarsometatarsi (one incomplete; II 37 mm, III 39 mm, IV 38 mm), phalanges II-1 (11 mm), phalanges II-2 (12 mm), pedal unguals II (13 mm straight, 16 mm on curve), phalanges III-1 (12 mm), phalanges III-2 (11 mm), phalanges III-3 (11 mm), pedal ungual III (~12 mm straight), phalanges IV-1 (8 mm), phalanges IV-2 (7 mm), phalanges IV-3 (7 mm), phalanges IV-4 (8 mm), pedal unguals IV (~13 mm straight), metatarsals V (6 mm) (Yuan, 2005)
?(CDPC-02-08-001; holotype of Didactylornis jii) skull (72 mm), mandibles (~55 mm), six cervical vertebrae, ten dorsal vertebrae, dorsal ribs, fragmentary gastralia, five sacral vertebrae, less than eight caudal vertebrae, pygostyle, scapulae (one incomplete; 67 mm), coracoids (one incomplete), incomplete furcula, humeri (135 mm), radii (~130 mm), ulnae (138 mm), scapholunare, pisiform, metacarpal I + phalanx I-1 (50 mm), manual unguals I (19 mm straight), carpometacarpus (II 59 mm, III 56 mm), phalanges II-1 (34 mm), phalanges II-2 (31 mm), manual unguals II (12 mm straight), phalanges III-1, phalanges III-2 (13 mm), partial ilium, pubes (90 mm), ischium (~31 mm), femora (80 mm), tibiotarsi (90 mm), fibula (~78 mm), metatarsals I (14 mm), phalanges I-1 (18 mm), pedal unguals I (one incomplete; 15 mm straight, 18 mm on curve), tarsometatarsi (II 42 mm, III 43 mm, IV 42 mm), phalanges II-1 (13 mm), phalanges II-2 (13 mm), pedal unguals II (14 mm straight, 18 mm on curve), phalanges III-1 (14 mm), phalanges III-2 (11 mm), phalanges III-3 (12 mm), pedal unguals III (13 mm straight, 19 mm on curve), phalanges IV-1 (9 mm), phalanges IV-2 (7 mm), phalanges IV-3 (10 mm), pedal unguals IV (13 mm straight, 16 mm on curve), metatarsal V (Yuan, 2005)
?(DNHM-D1197) specimen including skull (61.2 mm), dorsal vertebrae, ilium, pubis (83.6 mm), tibiotarsus (~94.6 mm), tarsometatarsus (~49 mm), phalanx I-1 (16.9 mm) and phalanx II-2 (12.8 mm) (Gao et al., 2012)
?(DNHM-D2523) specimen including dorsal vertebrae, coracoid (37.7 mm), humerus (133.5 mm), radius (127.6 mm), ulna (124.2 mm), metacarpal I (11.8 mm), phalanx I-1 (32.7 mm), manual ungual I (19.4 mm), metacarpal II (51.4 mm), phalanx II-1 (25.8 mm), metacarpal III (~33.8 mm), phalanx III-1 (20 mm), ilium, pubis (~72.8 mm), femur (71 mm), tibiotarsus (~85.7 mm), tarsometatarsus (42.8 mm) and phalanx I-1 (16.1 mm) (Gao et al., 2012)
(IVPP V13275) (1 kg) skull (~62 mm), mandible, dentary, atlas, cervical vertebrae, dorsal vertebrae, dorsal ribs, gastralia, sacrum, six or seven caudal vertebrae, pygostyle (~27 mm), scapulae (~71, ~71.5 mm), coracoids (36.7 mm), furcula (~41.5 mm), humeri (one incomplete; 122.6 mm), radii (120, 120.4 mm), ulnae (~123.6, ~124 mm), pisiforms, metacarpals I (~11, ~12 mm), phalanges I-1 (28.7, 30 mm), manual unguals I (~18.6 mm), carpometacarpi (II ~52, 51.3 mm, III ~49, 47 mm) phalanges II-1 (one partial; ~29 mm), phalanges II-2 (~26, 25.9 mm), manual unguals II (17.4 mm), phalanx III-1 (10.6 mm), ilia (55.3, 53 mm), pubis (~77.5 mm), ischium (~41.9 mm), femora (74.4, ~73.7 mm), tibiotarsi (80.6, 81.7 mm), fibula (~71, ~68 mm), metatarsal I (10.8 mm), phalanges I-1 (16 mm), pedal unguals I (17.9 mm), tarsometatarsi (~41.5, ~42 mm), pedal ungual II, pedal ungual III, pedal ungual IV, pedal phalanges, metatarsal V (9.6 mm), many gastroliths (2-2.5 mm) (Zhou and Zhang, 2003)
(IVPP V13276) (1 kg) skull (~64 mm), partial surangular, cervical vertebrae, dorsal vertebrae, dorsal ribs, fifteen pairs of gastralia, sacrum, caudal vertebrae, pygostyle (25.11 mm), coracoid (39.5 mm), furcula (42.4 mm), humerus (~123.2 mm), radius (123.3 mm), ulna (124 mm), pisiform, scapholunare, metacarpal I (12 mm), phalanx I-1 (~27 mm), manual ungual I (18.8 mm), carpometacarpus (II 52.9 mm, III 48.2 mm), phalanx II-1 (30.6 mm), phalanx II-2 (26.6 mm), manual ungual II (~17.7 mm), phalanx III-1 (10 mm), phalanx III-2 (9 mm), ilium (55.9 mm), pubes (80 mm), ischia, femora (72.1 mm), tibiotarsi (one proximal; 85.3 mm), fibula, phalanx I-1 (16.4 mm), pedal ungual I (~17 mm), tarsometatarsi (42.41 mm), phalanx II-1, phalanx II-2, pedal ungual II, phalanx III-1, phalanx III-2, phalanx III-3, pedal ungual III, pedal ungual IV, pedal claw sheaths, metatarsal V (Zhou and Zhang, 2003)
?(IVPP V13396; holotype of Sapeornis angustis) (subadult) skull (54.6 mm), mandibles, nine cervical vertebrae, two cervical ribs, eleven dorsal vertebrae, twenty-four dorsal ribs, fifteen to sixteen pairs of gastralia, five sacral vertebrae, seven caudal vertebrae, scapulae (52.4, 52.4 mm), coracoids (29.1 mm), furcula (42.3 mm), humeri (93.9, 93.1 mm), radii (91.1, 88 mm), ulnae (91.5, 88 mm), scapholunare, pisiform, metacarpals I (14.2, 11.9 mm), phalanges I-1 (24.1, 24.7 mm), manual unguals I (~10.6, 13.7 mm), metacarpals II (42.8, 41.3 mm), phalanges II-1 (22.3, 23.4 mm), phalanges II-2 (one proximal; 21.7, 21.7 mm), manual unguals II (13.1, 13.7 mm), metacarpals III (36 mm), phalanges III-1 (9.8, 7.5 mm), manual claw sheaths, ilia (30.4 mm), pubes (57.3, 58.5 mm), ischia (35.8 mm), femora (one incomplete; 58.2, 58.3 mm), tibiotarsi (68.5, 68.4 mm), fibulae (65.7 mm), distal tarsals III, distal tarsals IV, metatarsal I, phalanges I-1 (12.7, 13.1 mm), pedal unguals I (13.7, 13.7 mm), metatarsals II, phalanges II-1, phalanges II-2 (11.7 mm), pedal unguals II, metatarsals III (30, 33.1 mm), phalanges III-1, phalanges III-2 (one incomplete), partial phalanges III-3, pedal ungual III, metatarsals IV, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, pedal claw sheaths (Nesbitt et al., 2009)
(IVPP V22531) specimen including pygostyle (30.04 mm) and tarsometatars (43.93 mm) (Wang, O'Connor, Pan and Zhou, 2017)
(IVPP coll.) specimen including posterior cervical vertebrae, dorsal rib, scapulae, coracoids, furcula and humeri (Nesbitt et al., 2009)
?(LPM B00018; holotype of Shenshiornis primita) (subadult) skull (40 mm; ~46 mm in Gao et al., 2012), mandibles (40 mm), eleven cervical vertebrae, cervical ribs, eleven dorsal vertebrae, five dorsal ribs, gastralia, synsacrum, more than ten caudal vertebrae, few chevrons, ilia (44 mm), pubes (57 mm), ischium, femora (62 mm), tibiotarsi (64 mm), fibulae, distal tarsal, metatarsals I (8.9 mm), phalanges I-1, pedal ungual I, metatarsals II, phalanx II-1, phalanx II-2, pedal unguals II, metatarsals III (32 mm), phalanges III-1, phalanx III-3, pedal unguals III, metatarsals IV, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, metatarsal V (11.3 mm) (Hu et al., 2010)
?(LPM B00166) (one year old subadult) specimen including femur (80 mm) (Erickson et al., 2009)
?(JZPM-LSV-130) skull (60 mm), mandibles (53 mm), ten cervical vertebrae, dorsal vertebra, dorsal ribs, fragmentary gastralia, caudal vertebra, partial coracoids, furcula, incomplete humeri (114 mm), incomplete radii (115 mm), ulnae (one incomplete; 115 mm), scapholunares, pisiform, metacarpals I (12 mm), phalanges I-1 (~28.5 mm), manual unguals I (16 mm straight, 21 mm on curve), carpometacarpi (one partial; II 53 mm), phalanges II-1 (one partial; 22 mm), phalanges II-2 (one partial; ~14 mm), manual unguals II (13 mm straight, 18 mm on curve), femur (68 mm), tibiotarsi (78 mm), fibula (75 mm), metatarsals I, phalanges I-1 (15 mm), pedal unguals I (14 mm straight, 17 mm on curve), tarsometatarsi (II 38 mm, III 39 mm, IV 38 mm), phalanges II-1 (~8 mm), phalanges II-2 (10 mm), pedal unguals II (13 mm straight), phalanges III-1 (12 mm), phalanges III-2 (11 mm), phalanges III-3 (11 mm), pedal unguals III (13 mm straight), phalanges IV-1 (8 mm), phalanges IV-2 (7 mm), phalanges IV-3 (7 mm), phalanges IV-4 (8 mm), pedal unguals IV (11 mm straight, 15 mm on curve), pedal claw sheaths (Yuan, 2005)
Late Barremian-Early Aptian, Early Cretaceous
Jianshangou Beds of Yixian Formation, Liaoning, China
(DNHM-D3078) (490 g, subadult) skull (54.1 mm), sclerotic ring, mandible, nine cervical vertebrae, cervical ribs, dorsal vertebrae, dorsal ribs, gastralia, sacral vertebrae, three caudal vertebrae, scapulae (~48.4 mm), coracoids (~25.6, 25.9 mm), furcula, humeri (~98.8, 98.5 mm), radii (~94.5, 95.9 mm), ulnae (~94.3, 97.2 mm), scapholunare, semilunate carpal, distal carpal III, metacarpals I (10.1 mm), phalanges I-1 (24.8 mm), manual unguals I (12.3 mm), metacarpals II (43.3 mm), phalanges II-1 (22.6, ~22.6 mm), phalanges II-2 (20.1 mm), manual ungual II (10.7 mm), metacarpals III (37 mm), phalanges III-1 (10.5, 10.7 mm), phalanges III-2 (~6.2, 6.4 mm), ilium (38.1 mm), pubes (53.2, 52.6 mm), ischia (25.4, 27.9 mm), femora (56.7 mm), tibiotarsi (60.9, 62.8 mm), fibulae, metatarsal I (13.4 mm), phalanges I-1 (11.4, 11.4 mm), pedal unguals I (~8.8, 9 mm), metatarsals II (29.7 mm), phalanges II-1 (8.4 mm), phalanges II-2 (8.8 mm), pedal unguals II (~7.6, 8.3 mm), metatarsals III (32.7 mm), phalanges III-1 (10.2 mm), phalanges III-2 (8.6 mm), phalanges III-3 (8, 8.9 mm), pedal unguals III (9.1 mm), metatarsals IV (30 mm), phalanges IV-1 (6.1 mm), phalanges IV-2 (5.5 mm), phalanges IV-3 (~4.8 mm), phalanges IV-4 (~6.9, 7.6 mm), pedal unguals IV (~8.7, 6.9 mm), metatarsal V, pedal claw sheaths, remiges (Gao et al., 2012)
Barremian-Albian, Early Cretaceous
Jehol Group, Liaoning, China
(STM 15-1) incomplete skeleton including gastralia and femur (~45 mm) (Zheng et al., 2014)
(STM 15-2) material including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 15-3) incomplete skeleton including femur (90 mm) and feathers (Zheng et al., 2014)
(STM 15-4) incomplete skeleton including gastralia, femur (80 mm) and feathers (Zheng et al., 2014)
(STM 15-5) incomplete skeleton including gastralia, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 15-6) incomplete skeleton including gastralia and femur (57 mm) (Zheng et al., 2014)
(STM 15-7) incomplete skeleton including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 15-8) incomplete skeleton including gastralia and femur (63 mm) (Zheng et al., 2014)
(STM 15-9) incomplete skeleton including gastralia and femur (78 mm) (Zheng et al., 2014)
(STM 15-10) incomplete skeleton including gastralia and femur (80 mm) (Zheng et al., 2014)
(STM 15-11) incomplete skeleton including gastralia (Zheng et al., 2014)
(STM 15-12) incomplete skeleton including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 15-13) material including gastralia and femur (90 mm) (Zheng et al., 2014)
(STM 15-14) incomplete skeleton including femur (80 mm) (Zheng et al., 2014)
(STM 15-15) incomplete skeleton including gastralia and femur (76 mm) (Zheng et al., 2014)
(STM 15-16) (Zheng et al., 2014)
(STM 15-17) incomplete skeleton including gastralia and femur (68 mm) (Zheng et al., 2014)
(STM 15-18) incomplete skeleton including gastralia, femur (50 mm) and feathers (Zheng et al., 2014)
(STM 15-19) incomplete skeleton including gastralia and femur (67 mm) (Zheng et al., 2014)
(STM 15-20) incomplete skeleton (Zheng et al., 2014)
(STM 15-21) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 15-22) incomplete skeleton including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 15-23) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 15-24) incomplete skeleton including femur (70 mm) (Zheng et al., 2014)
(STM 15-25) material including femur (80 mm) (Zheng et al., 2014)
(STM 15-26) incomplete skeleton including femur (75 mm) (Zheng et al., 2014)
(STM 15-27) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 15-28) incomplete skeleton including femur (75 mm) and feathers (Zheng et al., 2014)
(STM 15-29) incomplete skeleton including gastralia and femur (93 mm) (Zheng et al., 2014)
(STM 15-30) incomplete skeleton including gastralia, femur (55 mm) and feathers (Zheng et al., 2014)
(STM 15-31) incomplete skeleton including gastralia and feathers (Zheng et al., 2014)
(STM 15-32) (several year old adult) incomplete skeleton including partial skull, vertebrae, dorsal ribs, gastralia, scapula, coracoid, furcula, humeri, radius, ulna, manus, ilium, femora (75 mm), tibiotarsi, pedes (Zheng et al., 2014)
(STM 15-33) material including gastralia and femur (64 mm) (Zheng et al., 2014)
(STM 15-34) material including femur (80 mm) and feathers (Zheng et al., 2014)
(STM 15-35) incomplete skeleton including gastralia, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 15-36) incomplete skeleton including gastralia, femur (68 mm) and feathers (Zheng et al., 2014)
(STM 15-37) incomplete skeleton including gastralia and femur (78 mm) (Zheng et al., 2014)
(STM 15-38) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 15-39) incomplete skeleton including gastralia and femur (82 mm) (Zheng et al., 2014)
(STM 15-40) incomplete skeleton including gastralia, femur (76 mm) and feathers (Zheng et al., 2014)
(STM 15-41) incomplete skeleton including gastralia and femur (56 mm) (Zheng et al., 2014)
(STM 15-42) incomplete skeleton including gastralia and femur (63 mm) (Zheng et al., 2014)
(STM 15-43) incomplete skeleton including gastralia and femur (56 mm) (Zheng et al., 2014)
(STM 15-44) incomplete skeleton including gastralia, femur (63 mm) and feathers (Zheng et al., 2014)
(STM 15-45) incomplete skeleton including dorsal vertebrae, dorsal ribs, gastralia, coracoids, furcula, humerus and femur (80 mm) (Zheng et al., 2014)
(STM 15-46) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 15-47) incomplete skeleton including gastralia and femur (80 mm) (Zheng et al., 2014)
(STM 15-48) incomplete skeleton including gastralia and femur (65 mm) (Zheng et al., 2014)
(STM 15-49) incomplete skeleton including gastralia and femur (73 mm) (Zheng et al., 2014)
(STM 15-50) incomplete skeleton including gastralia and femur (62 mm) (Zheng et al., 2014)
(STM 15-51) incomplete skeleton including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 15-52) material including gastralia (Zheng et al., 2014)
(STM 15-53) material including gastralia and feathers (Zheng et al., 2014)
(STM 15-54) incomplete skeleton including gastralia and femur (76 mm) (Zheng et al., 2014)
(STM 15-55) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 15-56) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 15-57) incomplete skeleton including femur (85 mm) (Zheng et al., 2014)
(STM 15-58) material including femur (58 mm) (Zheng et al., 2014)
(STM 15-59) incomplete skeleton including gastralia, femur (60 mm) and feathers (Zheng et al., 2014)
(STM 15-60) incomplete skeleton including gastralia and femur (68 mm) (Zheng et al., 2014)
(STM 15-61) incomplete skeleton including femur (78 mm) (Zheng et al., 2014)
(STM 15-62) material including gastralia (Zheng et al., 2014)
(STM 15-63) incomplete skeleton including femur (83 mm) (Zheng et al., 2014)
(STM 15-64) incomplete skeleton including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 15-65) incomplete skeleton including gastralia and femur (55 mm) (Zheng et al., 2014)
(STM 15-66) incomplete skeleton including gastralia, femur (54 mm) and feathers (Zheng et al., 2014)
(STM 15-67) (Zheng et al., 2014)
(STM 15-68) incomplete skeleton including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 15-69) incomplete skeleton including gastralia and femur (75 mm) (Zheng et al., 2014)
(STM 15-70) incomplete skeleton including gastralia and femur (81 mm) (Zheng et al., 2014)
(STM 15-71) incomplete skeleton including gastralia and femur (71 mm) (Zheng et al., 2014)
(STM 15-72) incomplete skeleton including gastralia, femur (64 mm) and feathers (Zheng et al., 2014)
(STM 15-73) incomplete skeleton (Zheng et al., 2014)
(STM 15-74) (Zheng et al., 2014)
(STM 16-1) material including gastralia and femur (60 mm) (Zheng et al., 2014)
(STM 16-2) material including gastralia and femur (~70 mm) (Zheng et al., 2014)
(STM 16-3) material including gastralia (Zheng et al., 2014)
(STM 16-4) material including gastralia and femur (~58 mm) (Zheng et al., 2014)
(STM 16-5) material including gastralia, femur (70 mm) and feathers (Zheng et al., 2014)
(STM 16-6) material including gastralia and femur (73 mm) (Zheng et al., 2014)
(STM 16-7) material including gastralia and femur (72 mm) (Zheng et al., 2014)
(STM 16-8) material including gastralia (Zheng et al., 2014)
(STM 16-9) material including gastralia and femur (65 mm) (Zheng et al., 2014)
(STM 16-10) material including gastralia and femur (70 mm) (Zheng et al., 2014)
(STM 16-11) material including gastralia (Zheng et al., 2014)
(STM 16-12) material including gastralia and femur (85 mm) (Zheng et al., 2014)
(STM 16-13) material including femur (77 mm) (Zheng et al., 2014)
(STM 16-14) material including femur (~63 mm) (Zheng et al., 2014)
(STM 16-15) material including femur (58 mm) (Zheng et al., 2014)
(STM 16-16) material including gastralia and femur (68 mm) (Zheng et al., 2014)
(STM 16-17) (Zheng et al., 2014)
(STM 16-18) skull, mandibles, nine cervical vertebrae, cervical ribs, eleven dorsal vertebrae, three partial dorsal ribs, gastralia, caudal vertebrae, chevrons, pygostyle, ilium, pubes, ischia, femora (54 mm), tibiae (65 mm), fibulae (one partial), tarsals, metatarsal I, phalanges I-1, pedal unguals I, metatarsals II, phalanges II-2, pedal unguals II, metatarsals III (33 mm), phalanx III-1, phalanx III-2, phalanges III-3, pedal unguals III, metatarsals IV, phalanx IV-4, pedal ungual IV, pedal fragments, retrices, leg remiges (Zheng et al., 2013)
(STM 16-19) pygostyle, pubes, hindlimb including tibia, phalanx I-1, pedal ungual I, metatarsus, pedal phalanges, pedal unguals, leg remiges (Zheng et al., 2013)
(STM 16-20) material including gastralia and femur (77 mm) (Zheng et al., 2014)
(STM 16-21) material including gastralia and femur (69 mm) (Zheng et al., 2014)
(STM 16-22) (Zheng et al., 2014)
Diagnosis- (after Zhou and Zhang, 2002) large size (also in Yandangornis); forelimb about 1.5 times hindlimb length.
(after Zhou and Zhang, 2003) long hypocleidium on furcula (also in enantiornithines); elongated oval foramen in deltopectoral crest of humerus (also in Confuciusornis); manual digit III consists of two phalanges.
(after Gao et al., 2012) dentary toothless (also in Jixiangornis, Zhongjianornis and Confuciusornithidae).
(proposed) sternum unossified (also in Anchiornis and Archaeopteryx); manual phalanx II-2 less than 98% of II-1 (also in Jixiangornis, Yandangornis, Dalianraptor and Changchengornis); metacarpal III straight (also in Scansoriopteryx, Dalianraptor, Zhongornis and some Confuciusornis specimens).
Other diagnoses- Zhou and Zhang (2002) included many symplesiomorphies (deltopectoral crest measures about one third of humeral length; first digit longer than metacarpus; fibula reaches tarsus; fifth metatarsal present) and an avebrevicaudan synapomorphy (pygostyle) in their diagnosis. The tibiofemoral ratio (104-121%) overlaps that of Shenzhouraptor, Jixiangornis and confuciusornithids. Some characters are only present in some specimens (short coracoid; distally pointed deltopectoral crest; tibiotarsus shorter than pubis).
Zhou and Zhang (2003) later added further apomorphies, but the robust furcula is shared with many other basal avialans.
Yuan (2005) included several additional symplesiomorphies were supposed to differentiate it from Didactylornis (phalanx I-1 shorter [i.e. unfused to metacarpal I]; manual digit III unfused to digit II; five phalanges in pedal digit IV). These characters in the Didactylornis holotype may eventually prove to be distinctive for adult Sapeornis.
Gao et al. (2012) listed spade-shaped teeth in their diagnosis, but the same could be said for some teeth of Archaeopteryx and those of Shenzhouraptor have not been described in depth. A pygostyle shorter than the metatarsus is also found in Changchengornis and some Confuciusornis specimens. A boomerang-shaped furcula with short hypocleidium is found in most basal avialans.
Comments- The holotype was discovered in 2000, and described in 2002 by Zhou and Zhang. It was originally restored with four phalanges on manual digit III, but was later found to have only two phalanges (Zhou and Zhang, 2002b). Similarly, the hypocleidium was unrecognized in the holotype (Zhou and Zhang, 2003) and is apparently broken in JZPM-LSV-130 as well. Zhou and Zhang (2003) redescribed the holotype and two new specimens (IVPP V13275 and V13276) in detail, while Yuan (2005) described two additional specimens (CAGS-03-07-08 and JZPM-LSV-130) in his unpublished thesis. Parts of the latter specimens are illustrated in his 2008 paper as well. Nesbitt et al. (2009) illustrate parts of two additional specimens, one labeled IVPP V13396 in the figure (8B) and the other (8C) IVPP unnumbered. However, the text states 8B is IVPP V13276 and 8C is V13275. This is obviously untrue, as they are not the specimens described by Zhou and Zhang (2003). The specimen IVPP V12675 is incorrectly stated in the text as being from Zhou and Zhang (2003), but is a paratype of the rodent Advenimus ulungurensis, so must be a mistake. IVPP V13396 was later described as Sapeornis angustis by Provini et al. (2009).
There may be more than one species involved, though not based on the characters authors have used to try to justify them so far. JZPM-LSV-130, LPM B00018 and the Omnivoropteryx holotype may have short dorsal premaxillary processes, unlike DNHM-D3078, IVPP V13275 and V13276. If the quadratojugal is correctly identified in JZPM-LSV-130, its lack of a dorsal process is also unlike DNHM-D3078 and IVPP V13276 but like LPM B00018. The supposed jugal of JZPM-LSV-130 is too slender, so is more probably a pterygoid. All preserved skulls are distorted to varying degrees, making elements' shapes differ markedly between specimens. The holotype has a somewhat distally expanded, but robust coracoid with a minimum shaft width 51% of its maximum proximodistal length. IVPP V13276 is similar in being robust (58%), but differs in having a lateral process, proximally projecting acromion and distolaterally slanting distal edge. DNHM-D3078 has a ratio of 40%. The coracoid of IVPP V13275 is visible in posterodorsal view, so is distorted, but seems roughly similar to both specimens. That of IVPP coll. (Nesbitt et al., 2009 figure 8C) is similar as well. However, the coracoid of CAGS-03-07-08 and the Didactylornis holotype are quite different, being an elongate strut with a very narrow neck (13%) and expanded proximal end (as in other pygostylians). A fragment from JZPM-LSV-130 seems similar. The coracoids of the holotype and CAGS-03-07-08 are the same length relative to their scapulae (~50%), showing the shorter coracoids are not simply due to breakage. If these differences can be confirmed and continue to be found to vary consistantly between specimens, the holotype, IVPP V13275, V13276 and IVPP coll. could be retained as Sapeornis chaoyangensis, while the other specimens would be sinousaorum.
Omnivoropteryx- The holotype of Omnivoropteryx was largely unprepared during its description and only x-rays are available, making most details impossible to discern. The specimen has reportedly since been fully prepared.
Czerkas and Ji included numerous characters in their diagnosis which are found in Sapeornis as well- short snout; procumbant premaxillary teeth; large external naris; ventrally curved dentary; humerus and ulna longer than femur and tibiotarsus; forelimb (humerus+radius+metacarpus) over 1.5 times length of hindlimb (femur+tibiotarsus+tarsometatarsus); tibiofemoral ratio 1.10 (1.04-1.21 in Sapeornis); pedal phalanx I-1 longer than other phalanges. The supposedly absent manual phalanx III-2 may simply be inconspicuous in the x-rays, as it is a tiny bone in Sapeornis. Indeed, the supposed III-1 in Omnivoropteryx seems to merely be the distal end of metacarpal III, leaving no phalanges from digit III visible. The unfused metatarsus may be due to its ontogenetic state, as the Omnivoropteryx holotype is smaller than specimens referred to Sapeornis chaoyangensis except DMNH-D3078. The authors further state that "significant skeletal differences between the two birds, especially regarding the proportions limbs and pubis" exist, but the slightly shorter ulna (158% of femoral length compared to 165-175% in Sapeornis) may be ontogenetic or individual variation, while the tibiotarsofemoral and metatarsofemoral ratios overlap the variation in Sapeornis. The pubofemoral ratio (84%) is indeed much smaller than in most Sapeornis (104-113%), but juvenile enantiornithines also have shorter pubes and the small DMNH-D3078 has a ratio of 93%. While maxillary teeth were reported to be indiscernable, a couple may be visible, comparable to Sapeornis. The first manual digit appears shorter than Sapeornis, but metacarpal I is not apparent in the x-rays, so phalanx I-1 may be placed too proximally. There may be additional differences, but this will not be confirmed until the specimen is properly prepared. The taxon is thus provisionally synonymized with Sapeornis chaoyangensis.
Czerkas and Ji interpreted the cranial similarities between Omnivoropteryx, Caudipteryx and Eoenantiornis as indicating close phylogenetic relationships, but there is little evidence to suggest this. Of the characters listed, the external naris of Caudipteryx is smaller than Omnivoropteryx, Eoenantiornis and almost every other avialan. Procumbant premaxillary teeth and short snouts are present in most basal members of maniraptoran lineages, including Archaeopteryx, basal ornithothoracines, Epidexipteryx, Jinfengopteryx and Incisivosaurus. The decurved dentary is found in many other basal birds too (including Shenzhouraptor, Dalianraptor and Jixiangornis), and Epidexipteryx, as well as derived oviraptorosaurs and therizinosaurs, but not basal varieties (e.g. Falcarius, Incisivosaurus, Protarchaeopteryx). The distribution suggests convergent development. Furthermore, omnivoropterygids possess no oviraptorosaurian characters, and share many synapomorphies with pygostylians. The latter include characters not obviously associated with flight (e.g. partially heterocoelous cervical centra; lateral fossae on posterior dorsal centra; no hyposphene-hypantrum articulations in dorsals; large number of sacral vertebrae; distally tapered scapula; short metacarpal I; short pubic symphysis; large posterodorsal ischial process; obturator process absent; trochanteric crest on femur; fused tibiotarsus). The conclusion is that while omnivoropterygids have superficially caudipterid-like skulls, the similarities are convergent and/or symplesiomorphic, and the family belongs in Avialae as all phylogenetic analyses have concluded.
Nearly all references have ignored Omnivoropteryx, even Gao et al.'s (2012) review of 'sapeornithid' taxonomy, perhaps due to the unusual method of publication and/or personal issues with Czerkas. One of the few exceptions is Dyke and Nudds (2008), who included the taxon without comment in their table of enantiornithines, almost certainly incorrectly. Pomeroy (2013) stated the diagnosis is based on taphonomy and ontogeny and that limb proportion differences are mostly due to ontogeny, so that Omnivoropteryx is a junior synonym of Sapeornis chaoyangensis as argued here. She did not seem to realize Omnivoropterygidae has priority over Sapeornithidae though.
Didactylornis- Yuan first named and described Didactylornis jii in his PhD thesis, but it was not published until three years later. The thesis contains additional measurements and figures compared to the published paper. In 2009, I posted the following discussion here, which concluded the taxon is synonymous with Sapeornis chaoyangensis. Yuan distinguished Didactylornis from the contemporaneous Sapeornis based on several features. Manual phalanx I-1 was supposed to be longer (85% of metacarpal II compared to 51-64%), but the first phalanx has the odd characteristic of extending proximally to the base of the carpometacarpus, with no separate metacarpal I. Thus it seems plausible that its length is due to fusion with metacarpal I, as in Sapeornis metacarpal I plus phalanx I-1 equal 72-87% of metacarpal II's length. The fusion would still be diagnostic however. Yuan furthermore stated the third manual digit was reduced to the point where it lacks phalanges, but this appears to be problematic as well. In the well preserved left manus, the structure labeled phalanx II-1 seems to be a composite element. There is a slot on its proximolateral portion that defines a narrow phalanx III-1, which may even be defined distally by a suture. Distal to this is another section that also seems separated from II-1 by a suture and ends lateral to digit II in a rounded distal end. Unlike phalanx III-2 in Sapeornis (CAGS-03-07-08, IVPP V13276), it does not taper distally, and extends to almost the end of phalanx II-1. The right manus seems to have a third digit as well, which equally long, though the entire manus and forearm are distorted. The final distinguishing character is the presence of only four phalanges (including the ungual) on digit IV in both pes, which is also known in the Solnhofen Archaeopteryx specimen. Unfortunately, pedal phalanges of digit IV are indistinct or disarticulated in most Sapeornis specimens (holotype, IVPP V13275 and 13276), making the extent of variation uncertain. The only other obvious difference between this specimen and Sapeornis is the strongly flared distal pubis, which forms an arrowhead shape, if not merely due to crushing each pubic boot out laterally. The codings for Sapeornis and Didactylornis are identical in Yuan's matrix (based on Clarke's matrix), except for the last two characters, which are apomorphies of Didactylornis discussed above. The newly described Sapeornis angustis is a subadult specimen which combines characters from Didactylornis (straight ulna; distally blunt manual phalanx III-2 fused to II-2) and Sapeornis (short manual phalanx III-1; five phalanges on pedal digit IV), reducing the likelihood the genera are distinct. It's also notable that the largest and most fully grown Archaeopteryx specimen differs from other specimens in some of the same ways (more manual fusion, reduced number of phalanges on pedal digit IV) that Didactylornis differs from the generally smaller Sapeornis specimens. Didactylornis is probably an ontogenetically older specimen of Sapeornis. Li et al. (2010) later considered it a probable synonym of Sapeornis, though merely said the differences "may easily result from poor preservation or damage". Later still, Gao et al. (2012) also argued for synonymy, considering the differences in manual and pedal phalanx counts to be probably taphonomic.
Sapeornis angustis- Provini et al. (2009) described the nearly complete skeleton IVPP V13396 as a new species of Sapeornis, S. angustis. This was based on several characters, but virtually all of them are known to be true in young specimens of other basal birds- small size; possibly fewer sacral vertebrae; narrower furcular rami; shorter hypocleidium; short forelimb (146% compared to 151-156% in specimens described as S. chaoyangensis, 149% in Omnivoropteryx); lower deltopectoral crest; small humeral fenestra; short pubis. Though only five sacrals are exposed, the posterior sacral end is covered by pelvic elements and leaves enough room for two vertebrae beneath the left pubis and ischium. Thus it may have seven sacrals as in other S. chaoyangensis. The less developed distal corner of the deltopectoral crest is also easily explainable by a young individual being less ossified. Numerous features of the specimen indicate a young age as well- sacral vertebrae not fused; poorly ossified distal ends of long bones; unfused carpometacarpus; unfused tarsometatarsus (while stated to be merely not well fused, there is no fusion apparent and distal tarsals can be seen in both feet though they are not mentioned). While the pubic symphysis is stated to be shorter in the diagnosis, it is stated to be equal in length to S. chaoyangensis in the text and the measurement table confirms this (both have symphyses 33% of pubic length). The shorter ulna (97% of humeral length) is very close to the length in specimens described as S. chaoyangensis (99-105%) and identical to the subadult Omnivoropteryx holotype, so is likely ontogenetic as well. Provini et al. stated the dorsal ribs of angustis were less curved than chaoyangensis, but while this seems true compared to IVPP V13276, it doesn't appear true in V13275. It is thus better explained by individual variation. The one remaining character is the longer metacarpal I (29-33% of metacarpal II length compared to 21-25% in Sapeornis chaoyangensis). It is not only confusing why Provini et al. would ignore ontogeny, but also why they would ignore Omnivoropteryx if they insist on taxonomic separation, as its holotype shares all the supposedly diagnostic characters of S. angustis where they can be observed (small size, short forelimb, low deltopectoral crest with unprojected distal edge, short pubis). It's especially telling that Omnivoropteryx is intermediate in size between angustis and chaoyangensis and also has intermediate deltopectoral crest development and forelimb length, though the pubis is shorter than either. After I posted the discussion above here in 2009, Gao et al. (2012) came to an identical conclusion using similar reasoning, though they stated remeasurement led to metacarpal I being only 25% of metacarpal II length, eliminating that difference as well.
Shenshiornis- Discovered in 2005, the partial skeleton LPM B00018 was described as Shenshiornis primita by Hu et al. (2010). They recognized it as a subadult specimen based on cervical ribs unfused to vertebrae, intercentral sutures visible on sacrum, and unfused metatarsals. This is further indicated by the small size, short pubis and perhaps unfused distal caudals. They distinguished it from Sapeornis based on several characters, though I (online, 2010) found these wanting. The prenarial portion of the premaxilla is supposedly shorter, but it is identical to the situation Omnivoropteryx and longer than JZPM-LSV-130. The apparently different proportions in IVPP V13275 and V13276 are due to them being in dorsal view. The left premaxilla of IVPP V13276 also has an elongate subnarial process, suggesting the seemingly short process on the right side and in JZPM-LSV-30 is due to breakage. Premaxillary and maxillary teeth are present in all omnivoropterygids, just as dentary teeth are absent. Didactylornis, IVPP V13275 and JZPM-LSV-30 all have subtriangular tooth crowns wider than their roots as well. The cervical centra are described as amphicoelous or amphiplatyan, while those of Sapeornis (Zhou and Zhang, 2003; Provini et al., 2009) and Didactylornis have been described as heterocoelous. However, basal avialans generally have variation within the neck, with posterior cervicals being amphicoelous while anterior cervicals are only semi-heterocoelous (heterocoelous anterior articular surface but primitively concave posterior one). This intermediate state has led to taxa like Confuciusornis being described as both amphicoelous and heterocoelous by different authors. In fact, both Confuiciusornis and Shenzhouraptor are coded as amphicoelous like Shenshiornis in Hu et al.'s matrix, although descriptions of both genera have indicated they have the semiheterocoelous state. The photographed cervicals certainly don't rule out a semiheterocoelous condition in Shenshiornis, and considering the issues above, I don't view this as a definitive or distinct character of the taxon. Though most specimens are not preserved and/or illustrated in sufficient detail, at least CAGS-03-07-08 shares the elongate posterior cervical postzygapophyses of Shenshiornis. The new genus was said to differ from Sapeornis angustis and Didactylornis in having seven sacrals, as in S. chaoyangensis. Yet the posterior sacrum of S. angustis is hidden and has enough space for two other vertebrae. In Didactylornis, the sacrum is stated to be poorly preserved and the figure suggests it is broken and partially covered by other elements. Notably Yuan (2005) coded Didactylornis as having the same number of sacrals as Sapeornis, even though he wrote only five could be observed. Hu et al. state more than ten free caudal vertebrae are preserved in Shenshiornis. IVPP V13275 has six or seven, S. angustis has at least seven, and Didactylornis' number is estimated at less than eight. However, the caudal series in Shenshiornis is poorly preserved and only loosely articulated. Even if true, the lack of distal fusion may be ontogenetic as in Zhongornis and some enantiornithines, as this specimen is smaller than any Sapeornis with a preserved pygostyle. The anteriorly pointed ilium is not necessarily different from other specimens (which are hidden or broken), and indeed seems to be the case in the fragmentary right ilium of CAGS-03-07-08. While the S. chaoyangensis holotype was schematically illustrated as having shorter rounded preacetabular processes on both ilia, the photo of the right ilium shows it to be fragmented and partly covered anteriorly by elements not indicated in the original figure. Thus the shape and completeness of the left ilium is also called into question. The short pubis is expected in a subadult and is longer (~92%) than in Omnivoropteryx (84%). The supposedly long metatarsal I (28% of metatarsal III) is indeed a bit longer than in IVPP V13275 (26%), but is the same as in CAGS-03-07-08 and actually shorter than in Didactylornis (33%). Metatarsal V (35% of metatarsal III, not ~40% as stated in the diagnosis) is also supposedly long, and is actually longer than the available measurements for CAGS-03-07-08 (15%) and IVPP V13275 (23%). In CAGS-03-07-08 at least, the elements may only be shaft fragments as one doesn't extend to the proximal tarsometatarsal edge while the other lies diagonally across metatarsals III and IV. Note too that most specimens (including the Sapeornis holotype) cannot be measured for this ratio, which has yet to be studied ontogenetically. Thus of the characters listed in Shenshiornis' diagnosis, only the metatarsal V 12% longer than IVPP V13275 is even possibly valid and could not be used to divide most omnivoropterygid specimens in any case. Like Omnivoropteryx and Sapeornis angustis, there is no reason to consider Shenshiornis anything other than a young Sapeornis chaoyangensis. Also like S. angustis, it's deplorable the authors did not acknowledge the existence of Omnivoropteryx because that genus also has the short prenarial rostrum and short pubis they see as diagnosing Shenshiornis. Gao et al. (2012) later came to the same conclusion regarding Shenshiornis' synonymy, though noted metatarsals I and V are both ~25% in Shenshiornis and confirmed additional Sapeornis specimens have a pointed preacetabular process.
References- Czerkas and Ji, 2002. A preliminary report on an omnivorous volant bird from Northeast China. Feathered Dinosaurs and the Origin of Flight. The Dinosaur Museum Journal. 1, 127-135.
Zhou and Zhang, 2002a. Largest bird from the Early Cretaceous and its implications for the earliest avian ecological diversification. Naturwissenschaften. 89, 34-38.
Zhou and Zhang, 2002b. A long-tailed, seed-eating bird from the Early Cretaceous of China. Nature. 418, 405-409.
Zhou and Zhang, 2003. Anatomy of the primitive bird Sapeornis chaoyangensis from the Early Cretaceous of Liaoning, China. Canadian Journal of Earth Sciences. 40, 731-747.
Yuan, 2005. Restudy on sapeornithids from the Lower Cretaceous of Yixian County, Liaoning. PhD Thesis. China University of Geosciences. 157 pp.
Dyke and Nudds, 2008. The fossil record and limb disparity of enantiornithines, the dominant flying birds of the Cretaceous. Lethaia. 42(2), 248-254.
Yuan, 2008. A new genus and species of Sapeornithidae from Lower Cretaceous in Western Liaoning, China. Acta Geologica Sinica. 82(1), 48-55.
Nesbitt, Turner, Spaulding, Conrad and Norell, 2009. The theropod furcula. Journal of Morphology. 270, 856-879.
Provini, Zhou and Zhang, 2009. A new species of the basal bird Sapeornis from the Early Cretaceous of Liaoning, China. Vertebrata PalAsiatica. 47(3), 194-207.
Erickson, Rauhut, Zhou, Turner, Inouye, Hu and Norell, 2009. Was dinosaurian physiology inherited by birds? Reconciling slow growth in Archaeopteryx. PLoS ONE. 4(10), e7390.
Hu, Li, Hou and Xu, 2010. A new sapeornithid bird from China and its implication for early avian evolution. Acta Geologica Sinica. 84(3), 472-482.
Li, Sullivan, Zhou and Zhang, 2010. Basal birds from China: A brief review. Chinese Birds. 1(2), 83-96.
Mortimer, online 2010. http://theropoddatabase.blogspot.com/2010/08/shenshiornis-is-gasp-another-young.html
Chiappe and Pomeroy, 2012. A taxonomic revision of the Sapeornithidae (Aves: Pygostylia) from Liaoning Province, China. Journal of Vertebrate Paleontology. Program and Abstracts 2012, 77-78.
Gao, Chiappe, Zhang, Pomeroy, Shen, Chinsamy and Walsh, 2012. A subadult specimen of the Early Cretaceous bird Sapeornis chaoyangensis and a taxonomic reassessment of sapeornithids. Journal of Vertebrate Paleontology. 32(5), 1103-1112.
Pomeroy, 2013. Is Omnivoropteryx sinousaorum a sapeornithid bird? Journal of Vertebrate Paleontology. Program and Abstracts 2013, 192.
Zheng, Zhou, Wang, Zhang, Zhang, Wang, Wei, Wang and Xu, 2013. Hind wings in basal birds and the evolution of leg feathers. Science. 339, 1309-1312.
O'Connor and Chang, 2014. Hindlimb feathers in paravians: Primarily "wings" or ornaments? Zoologicheskii Zhurnal. 93(10), 1166-1172.
Zheng, O'Connor, Wang, Wang, Zhang and Zhou, 2014. On the absence of sternal elements in Anchiornis (Paraves) and Sapeornis (Aves) and the complex early evolution of the avian sternum. Proceedings of the National Academy of Sciences. 111(38), 13900-13905.
O'Connor and Chang, 2015. Hindlimb feathers in paravians: Primarily "wings" or ornaments? Biology Bulletin. 42(7), 616-621.
Wang and Zhou, 2017 (online 2016). A new adult specimen of the basalmost ornithuromorph bird Archaeorhynchus spathula (Aves: Ornithuromorpha) and its implications for early avian ontogeny. Journal of Systematic Palaeontology. 15(1), 1-18.
Wang, O'Connor, Pan and Zhou, 2017. A bizarre Early Cretaceous enantiornithine bird with unique crural feathers and an ornithuromorph plough-shaped pygostyle. Nature Communications. 8:14141.

Pygostylia Chatterjee, 1997
Definition- (Confuciusornis sanctus + Passer domesticus) (Turner, Makovicky and Norell, 2012; modified from Chiappe, 2001)
Other definitions- (fused distal caudal vertebrae homologous with Vultur gryphus) (Gauthier and de Queiroz, 2001)
= Aerialae Ji and Ji, 2001
Diagnosis- premaxillae fused anteriorly (also in Caenagnathoidea; absent in Pengornis); dorsal centra with enlarged lateral fossae (also in Patagonykus, Beipiaosaurus, Rahonavis, Zhongjianornis and last two dorsals of Sapeornis; absent in juvenile confuciusornithids, Longipteryx, Eocathayornis, Patagopteryx, Apsaravis, Enaliornis and Aves); sternal plates fused (also in Parvicursorinae, some Microraptor specimens, Jixiangornis and Yandangornis); biceps tubercle or scar present on ulna (also in Mononykus and some dromaeosaurids; absent in Protopteryx); posterodorsal ischial process contacts ilium (also in Zhongjianornis; absent in Euornithes); retinaculi extensor tubercle present on anterodistal tibiotarsus (also in Troodon; absent in Soroavisaurus and Archaeorhynchus); cartilaginous tibial sulcus on posterodistal tibiotarsus.
References- Turner, Makovicky and Norell, 2012. A review of dromaeosaurid systematics and paravian phylogeny. Bulletin of the American Museum of Natural History. 371, 1-206.

Qiliania Ji, Atterholt, O'Connor, Lammana, Harris, Li, You and Dodson, 2011
Q. graffini Ji, Atterholt, O'Connor, Lammana, Harris, Li, You and Dodson, 2011
Aptian, Early Cretaceous
Xiagou Formation, Gansu, China
Holotype- (GSGM-F00003; = CAGS-IG-05-CM-006) (adult) partial ilium, pubis (17.5 mm), ischium (11.5 mm), femur (24.3 mm), tibiotarsus (32.2 mm), metatarsal I (3.2 mm), phalanx I-1 (4.2 mm), pedal ungual I (4.4 mm), tarsometatarsus (II 19.2, III 20.3 mm), phalanx II-1 (3.7 mm), phalanx II-2 (4.8 mm), pedal ungual II (4.9 mm), phalanx III-1 (4.6 mm), phalanx III-2 (4.0 mm), phalanx III-3 (4.2 mm), pedal ungual III (5.8 mm), phalanx IV-1, phalanx IV-2 (2.3 mm), phalanx IV-3 (2.4 mm), phalanx IV-4 (2.8 mm), pedal ungual IV (4.4 mm), pedal claw sheaths
Paratype- (GSGM-F00004; = CAGS-IG-04-CM-006) (adult) distal femur, tibiotarsus (32.4 mm), proximal tarsometatarsus
Diagnosis- (after Ji et al., 2011) distal quarter of pubis deflected ventrally; tibiotarsus very long and slender, with mid-shaft mediolateral width to proximodistal length ratio of less than 0.05 and proximodistal length 133% that of femur; tibiotarsus with anteroposteriorly elongate and subrectangular proximal articular surface, well-developed cnemial crest, and deep distolateral fossa; tarsometatarsus very long and slender (63% of proximodistal length of tibiotarsus).
Comments- Lamanna et al.'s (2005) abstract matches the Qiliania holotype best, though it may refer to an otherwise undeswcribed enantiornithine specimen. Ji et al. (2011) included Qiliania in a version of O'Connor et al.'s (2009) matrix, resulting in it being an enantiornithine sister to Eoalulavis and Iberomesornis. However, they excluded Rapaxavis and Longicrusavis a priori without justification. When these are included, Qiliania is a confuciusornithid based on its short ischium, though it goes back to an enantiornithine position with the addition of one step. It is here placed in Pygostylia incertae sedis pending further study. Perhaps relevant is that when originally announced in an abstract, Atterholt et al. (2009) believed it had many enantiornithine characters, but their "cladistic analysis was unable to substantiate this conclusion."
References- Lamanna, You, Ji, Lu, Ji and Chiappe, 2005. A new enantiornithine partial skeleton from the Early Cretaceous of northwestern China. Journal of Vertebrate Paleontology. 25(3), 81A-82A.
Atterholt, Lamanna, O'Connor, Li and Ji, 2009. Phylogenetic and ecomorphological conundrums revealed by an enigmatic new Early Cretaceous bird (Enantiornithes) from Northwestern China. Journal of Vertebrate Paleontology. 29(3), 56A.
O'Connor, 2009. A systematic review of Enantiornithes (Aves: Ornithothoraces). PhD thesis, University of Southern California. 586 pp.
Ji, Atterholt, O'Connor, Lammana, Harris, Li, You and Dodson, 2011. A new, three-dimensionally preserved enantiornithine bird (Aves: Ornithothoraces) from Gansu Province, north-western China. Zoological Journal of the Linnean Society. 162, 201-219.

Confuciusornithiformes Hou, Zhou, Gu and Zhang, 1995
Definition- (Confuciusornis sanctus <- Enantiornis leali, Passer domesticus) (Martyniuk, 2012)
= Orthornithes Ji and Ji, 2001
= Confuciusornithes Zelenkov in Zelenkov and Kurochkin, 2015
= Confuciusornithidae sensu Sereno, in press
Definition- (Confuciusornis sanctus <- Passer domesticus)
Comments- As a common stand-in for Pygostylia, Confuciusornis has had some odd relationships in a couple recent analyses (sister to Oviraptorosauria in Maryanska et al., 2002; sister to Microraptor in Mayr et al., 2005). But without additional pygostylians tested in those analyses, it's difficult to justify using those sister taxa as additional specifiers for Confuciusornithiformes.
References- Hou, Zhou, Gu and Zhang, 1995. Confuciusornis sanctus, a new Late Jurassic sauriurine bird from China. Chinese Science Bulletin. 40(18), 1545-1551.
Martyniuk, 2012. A Field Guide to Mesozoic Birds and Other Winged Dinosaurs. Vernon, New Jersey. Pan Aves. 189 pp.
Zelenkov and Kurochkin, 2015. Class Aves. In Kurochkin, Lopatin and Zelenkov (eds.). Fossil vertebrates of Russia and adjacent countries. Part 3. Fossil Reptiles and Birds. GEOS.  86-290.

Elopterygidae Lambrecht, 1933
Elopteryginae Lambrecht, 1933 sensu Le Loeuff, Buffetaut, Mechin and Mechin-Salessy, 1992
Comments- Lambrecht (1933) erected Elopterygidae within Sulida (his Sulides), for Elopteryx (including what would become the types of Bradycneme and Heptasteornis), Eostega and Actiornis. Eostega is an Eocene taxon known from incomplete mandibles which cannot be compared to Elopteryx, but have been recently referred to Sulidae (Mlikovsky, 2007). Actiornis is also Eocene and known from a proximal ulna which cannot be compared to Elopteryx either, and has been referred to Threskiornithidae since Harrison and Walker (1976). Le Loeuff et al. (1992) resurrected the family-level taxon for what they considered dromaeosaurs, again synonymizing Elopteryx, Bradycneme and Heptasteornis, and also referring a femur (MDE-D203) from Metisson (Fox-Amphoux, Var), and an anterior dorsal vertebra (MDE-D01), posterior sacral vertebra (MDE coll.) and several fragmentary dorsal ribs from Roques-Hautes (Bouches-du-Rhone). These materials have since been referred to Variraptor (Le Loeuff and Buffetaut, 1998). Le Loeuff et al. largely grouped these remains together based on geography and the peculiar wrinkled bone texture, but this has since been described in a parvicursorine distal femur (FGGUB R.1957) and the basal avialan Balaur, both from Romania. Thus it seems to be related to locality instead of phylogeny.
References- Lambrecht, 1933. Handbuch der Palaeornithologie. Gebr�der Borntraeger. 1024 pp.
Harrison and Walker, 1976. Birds of the British Upper Eocene. Zoological Journal of the Linnean Society. 59(4), 323-351.
Le Loeuff, Buffetaut, Mechin and Mechin-Salessy, 1992. The first record of dromaeosaurid dinosaur (Saurichia, Theropoda) in the Maastrichtian of Southern Europe: palaeobiogeographical implications. Bulletin de la Societe Geologique de France. 163(3), 337-343.
Le Loeuff and Buffetaut, 1998. A new dromaeosaurid theropod from the Upper Cretaceous of Southern France. Oryctos. 1, 105-112.
Mlikovsky, 2007. Taxonomic identity of Eostega lebedinskyi Lambrecht, 1929 (Aves) from the Middle Eocene of Romania. Annalen des Naturhistorischen Museums in Wien. 109A, 19-27.
Elopteryx Andrews, 1913
E. nopcsai Andrews, 1913
Late Maastrichtian, Late Cretaceous
Sinpetru Beds, Romania
Holotype- (NHMUK A1234) proximal femur (~150 mm)
Paratype- (NHMUK A1235) proximal femur (~150 mm) (Lambrecht, 1929)
Comments- Andrews (1913) originally described Elopteryx as a pelecaniform, referring the distal tibiotarsus NHMUK A4329 to the same individual. Lambrecht (1929) referred two more distal tibiotarsi (NHMUK A1528 and 1588) to it, as well as an additional proximal femur (NHMUK A1234). Later, Lambrecht (1933) created the family Elopterygidae for the genus. Harrison and Walker (1975) removed the tibiotarsi, making them the type specimens of Bradycneme and Heptasteornis. Grigorescu and Kessler (1981) referred a distal femur (FGGUB R.351) to this taxon, which was reidentified as a ceratosaur by Csiki and Grigorescu (1998), then more certainly as a distal hadrosaurid metatarsal by Kessler et al. (2005). Jurcsak and Kessler (1986) reported a skull (FGGUB 1007) they referred to Elopteryx which supposedly supports an assignment to Pelecaniformes, but this has turned out to be from a sauropod (Csiki, pers. comm. 2007; illustrated in Weishampel et al., 1991). Le Loeuff et al. (1992) resynonymized Heptasteornis and Bradycneme with Elopteryx based on their bone texture. They also described a femur (MDE-D203), anterior dorsal vertebra (MDE-D01), posterior sacral vertebra (MDE coll.) and several fragmentary dorsal ribs from the Gres a Reptiles Formation of France which they believed were congeneric or at least related to Elopteryx. Le Loeuff et al. believed these remains were most closely related to dromaeosaurids, though perhaps deserving their own family or subfamily (Elopterygidae or Elopteryginae). Le Loeuff and Buffetaut (1998) referred the two vertebrae to their new dromaeosaurid genus Variraptor. The femur was only stated to share general characteristics with Elopteryx (reduced fourth trochanter, posterior trochanter, "shape and size") while differing in having a linear capital ligament fossa and absent fourth trochanter. It probably belongs to a distinct taxon of maniraptoran, and as the tibiotarsi and vertebrae are not even comparable to Elopteryx, the concept of a European clade of elopterygines or elopterygids is morphologically baseless. The Elopteryx holotype was identified as a derived maniraptoran by Csiki and Grigorescu (1998) and later as a troodontid or non-euornithine pygostylian ("non-ornithuromorphan pygostylian") by Naish and Dyke (2004). Kessler et al. (2005) describe a mononykine distal femur (FGGUB R.1957) as Elopteryx based on bone texture, synonymizing Heptasteornis and Bradycneme with the genus again, and refer the taxon to Alvarezsauridae. I prefer to assign the femur to the mononykine Heptasteornis, while keeping Elopteryx separate as it differs from alvarezsaurids in some ways (posterior trochanter and capital ligament fossa present).
References- Andrews, 1913. On some bird remains from the Upper Cretaceous of Transylvania. Geological Magazine. 5, 193-196.
Lambrecht, 1929. Mesozoische und tertiare Vogelreste aus Siebenburgen. In Csiki (ed.). Xe Congres International de Zoologie. 1262-1275.
Lambrecht, 1933. Handbuch der Palaeornithologie. Gebr�der Borntraeger. 1024 pp.
Harrison and Walker, 1975. The Bradycnemidae, a new family of owls from the Upper Cretaceous of Romania. Palaeontology. 18(3), 563-570.
Grigorescu and Kessler, 1981. A new specimen of Elopteryx nopcsai from the dinosaurian beds of Hateg Basin. Revue Roumaine de Geologie, Geophysique et Geographie, Geologie. 24, 171-175.
Jurcsak and Kessler, 1986. The evolution of the Roumanien bird fauna, Part I. The history of the studies. Crisia 16, 577-615, Oradea. [in Roumanian, with English abstract]
Kessler, 1987. New contributions to the knowledge about the Lower and Upper Cretaceous birds from Romania. Occasional Papers of the Tyrrell Museum of Palaeontology. 3, 133-135.
Weishampel, Grigorescu and Norman, 1991. The dinosaurs of Translyvania.National Geographic Research and Exploration. 7(2), 196-215.
Le Loeuff, Buffetaut, Mechin and Mechin-Salessy, 1992. The first record of dromaeosaurid dinosaur (Saurichia, Theropoda) in the Maastrichtian of Southern Europe: palaeobiogeographical implications. Bulletin de la Societe Geologique de France. 163(3), 337-343.
Le Loeuff and Buffetaut, 1998. A new dromaeosaurid theropod from the Upper Cretaceous of Southern France. Oryctos. 1, 105-112.
Csiki and Grigorescu, 1998. Small Theropods from the Late Cretaceous of the Hateg Basin (Western Romania) - an unexpected diversity at the top of the food chain. Oryctos. 1, 87-104.
Naish and Dyke, 2004. Heptasteornis was no ornithomimid, troodontid, dromaeosaurid or owl: the first alvarezsaurid (Dinosauria: Theropoda) from Europe. Neus Jahrbuch f�r Geologie und Pal�ontologie. 7, 385-401.
Kessler, Grigorescu and Csiki, 2005. Elopteryx revisited - a new bird-like specimen from the Maastrichtian of the Hateg Basin. Acta Palaeontologica Romaniae. 5, 249-258.

Confuciusornithidae Hou, Zhou, Gu and Zhang, 1995
Definition- (Confuciusornis sanctus + Changchengornis hengdaoziensis) (Chiappe et al., 1999)
Other definitions- (Confuciusornis sanctus <- Passer domesticus) (Sereno, in press)
Diagnosis- (after Ji et al., 1999) premaxilla toothless (also in Shenzhouraptor, Jixiangornis, Yandangornis, Zhongjianornis, Boluochia+Gobipteryx, Chaoyangiidae, Ornithurae); dentary toothless (also in Jixiangornis, Omnivoropterygidae, Zhongjianornis, Gobipteryx, Archaeorhynchus, Apsaravis and Aves); enlarged deltopectoral crest; manual ungual II much smaller than manual ungual I.
(after Chiappe et al., 1999) manual phalanx III-2 >150% of III-1 in length.
(proposed) extremely reduced antorbital fenestra; dentary symphysis fused (polymorphic; also in Shenzhouraptor, Gobipteryx, Apsaravis and Aves); scapula expanded distally; scapulocoracoid fused in adults; coracoid glenoid facet proximal to coracoid tubercle (also in non-avialans); elongate metatarsal V compared to tarsmetatarsal length; two elongate retrices with reduced barbs (also in Enantiornithes).
Other diagnoses- Ji et al. (1999) included several other characters in their diagnosis. The forked anteromedian dentary margin is plesiomorphically due to a lack of complete fusion. The lack of a promaxillary fenestra and round maxillary fenestra are pygostylian symplesiomorphies. The V-shaped caudal sternal margin is another symplesiomorphy, seen in Shenzhouraptor, Protopteryx and others.
Chiappe et al. (1999) listed an additional supposed synapomorphy. The unfused metacarpal I is a symplesiomorphy however.
Comments- Hou et al. (1999) erected both Confuciusornithidae and Confuciusornithiformes as monotypic taxa for Confuciusornis sanctus. The description of Changchengornis by Ji et al. (1999) first made Confuciusornithidae a useful taxon, though Confuciusornithiformes has been unused except by those authors who assign every Mesozoic bird to an order until Martyniuk (2012).
Sereno (in press) wished to change the definition so that as more members of the confuciusornithid stem are discovered, it would be able to refer them to the family. Another solution would be to use Confuciusornithiformes (Hou et al., 1995) for the stem, which is what Martyniuk has done.
References- Hou, Zhou, Gu and Zhang, 1995. Confuciusornis sanctus, a new Late Jurassic sauriurine bird from China. Chinese Science Bulletin. 40(18), 1545-1551.
Chiappe, Ji, Ji and Norell, 1999. Anatomy and systematics of the Confuciusornithidae (Theropoda: Aves) from the Late Mesozoic of Northeastern China. Bulletin of American Museum of Natural History. 242, 1-89.
Ji, Chiappe and Ji, 1999. A new Late Mesozoic confuciusornithid bird from China. Journal of Vertebrate Paleontology. 19(1), 1-7.
Zinoviev, 2009. An attempt to reconstruct the lifestyle of confuciusornithids (Aves, Confuciusornithiformes). Paleontological Journal. 43(4), 444-452.

"Proornis" Lim, 1993 vide Pak and Kim, 1996
"P. coreae" Lim, 1993 vide Pak and Kim, 1996
Barremian-Albian, Early Cretaceous
Sinuiju Series, North Korea
Material- (Kinnissei University Natural Sciences Museum coll.) skull, anterior cervical vertebrae, partial dorsal rib, incomplete humerus, radius, ulna, semilunate carpal, carpal, metacarpal I, phalanx I-1, manual ungual I, carpometacarpus, phalanx II-1, phalanx II-2, manual ungual II, phalanx III-1, phalanx III-2, phalanx III-3, manual ungual III, feathers (Anonymous, 1993)
distal radius, distal ulna, scapholunare, semilunate carpal, metacarpal I, phalanx I-1, manual ungual I, metacarpal II, phalanx II-1, metacarpal III, phalanx III-1, phalanx III-2 (Gao et al., 2009)
Comments- This specimen was discovered in 1993 and first reported as being Late Jurassic in age, with photographs in the popular press in Korea (October 22, 1993 issue of Nodong Sinmum). It was featured in a 1994 issue of the magazine Korean Pictorial as the "North Korean Archaeopteryx", with a color photo. Molnar (vide Morer-Chauvire, 1994) reported on this in the SAPE newsletter, noting several details including the repository and a few differences from Archaeopteryx (metacarpals shorter compared to radius; digit III phalanges shorter compared to metacarpal III; only three phalanges on manual digit III [which is incorrect]). Similarly, Chiappe (1995) noted that differences in wing proportions cast doubt on its assignment to Archaeopteryx. Pak and Kim (1996) claimed the bird was named "Proornis coreae" by Lim in 1993, by order of Kim Il Sung, although such a publication has not been located to my knowledge. Thus the exact status of the name is uncertain, since the extent of the original description is unknown and no known publication is sufficient as of yet. It remains a nomen nudum on this site until proven otherwise. Pak and Kim also provide a photograph of the specimen, but do not describe it. Lee et al. (2001) credit the name to Paek [sic] and Kim, and distinguish it from Archaeopteryx based on the digits being shorter than the metacarpals (though this is untrue). In 2001, I used the available photo to present a preliminary description of the specimen on the DML, concluding it was a confuciusornithid. Li and Gao (2007) recently commented further on the specimen in an SVP abstract followed by Gao et al. (2009), where they also identify it as a confuciusornithid. This is based on the deep rectangular deltopectoral crest, reduced manual ungual II and phalanx III-2 much longer than III-1.
References- Anonymous, 1993. Nodong Sinmum. October 22, 1993.
Lim, 1993.
Anonymous?, 1994. Korean Pictorial. Volume 2.
Morer-Chauvire, 1994. Society of Avian Paleontology and Evolution Information Letter. Number 8.
Chiappe, 1995. The first 85 million years of avian evolution. Nature. 378, 349-355.
Pak and Kim, 1996. Section 5. Mesozoic Era. In Paek, Kang and Jon (eds.). Geology of Korea, Foreign Languages Books Publishing House, Pyongyang. 155-188.
Lee, Yu and Wood, 2001. A review of vertebrate faunas from the Gyeongsang Supergroup (Cretaceous) in South Korea. Palaeogeography, Palaeoclimatology, Palaeoecology. 165(3), 357-373.
Mortimer, DML 2001. https://web.archive.org/web/20190416181244/http://dml.cmnh.org/2001May/msg00859.html
Li and Gao, 2007. Lower Cretaceous vertebrate fauna from the Sinuiju basin, North Korea as evidence of geographic extension of the Jehol biota into the Korean peninsula. Journal of Vertebrate Paleontology. 27(3), 106A.
Gao, Li, Wei, Pak and Pak, 2009. Early Cretaceous birds and pterosaurs from the Sinuiju series, and geographic extension of the Jehol biota into the Korean peninsula. Journal of the Paleontological Society of Korea. 25(1), 57-61.

Changchengornis Ji, Chiappe and Ji, 1999
C. hengdaoziensis Ji, Chiappe and Ji, 1999
Late Barremian-Early Aptian, Early Cretaceous
Jianshangou Beds of Yixian Formation, Liaoning, China
Holotype- (GMV 2129a/b) (138 g; adult male) incomplete skull, incomplete mandibles, four cervical vertebrae, over seven dorsal vertebrae, partial dorsal ribs, gastralia, sacrum, six caudal vertebrae, pygostyle, scapulocoracoids, furcula, incomplete sternum, partial humeri (33.53 mm), partial radii (31.07, 30.35 mm), partial ulnae (31.97 mm), metacarpal I (7.76 mm), phalanges I-1, manual ungual I, metacarpals II (17.07 mm), phalanges II-1 (10.67, 10.91 mm), phalanges II-2 (10.71, 10.89 mm), manual ungual II, partial metacarpals III, phalanges III-1, phalanges III-2, phalanges III-3, manual ungual III, manual claw sheaths, partial ilia, pubes, femora (33.46, 33.02 mm), tibiotarsi (36.59, 36.86 mm), fibulae (20.93, ~19.9 mm), metatarsals I (5.21, 5.13 mm), phalanges I-1, pedal unguals I, tarsometatarsi (20.64, 20.34 mm), phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, metatarsal V, pedal claw sheaths, body feathers, remiges, retrices
Diagnosis- (after Ji et al., 1999) decurved premaxilla; surangular rises sharply at posterior edge of external mandibular fenestra; metacarpal I >40% of metacarpal II.
(after Chiappe et al., 1999) rostrum <40% of cranial length; tubercle on center of posterior furcula (also in Jixiangornis); furcula grooved anteriorly and posteriorly; manual phalanges II-1 and II-2 subequal in length (also in Jixiangornis, Dalianraptor, Yandangornis and Omnivoropterygidae); metatarsals III and IV fuse distally (also in Yandangornis).
(proposed) humerus subequal to femur in length; brevis fossa present(?).
Other diagnoses- Ji et al. (1999) also used three other characters in their diagnosis. The mandible being much shorter than the skull cannot be confirmed because the anterior dentary does not connect to the posterior mandible in the holotype. The absent proximal humeral foramen is plesiomorphic. The elongated hallux compared to digit II is within the range of variation of Confuciusornis (e.g. IVPP V11308). Chiappe et al. (1999) proposed the narrow posteromedian sternal process as an apomorphy, but this is also within the range of Confuciusornis (e.g. IVPP V11521). Finally, they also included the plesiomorphically non-excavated posterior metatarsus in their diagnosis.
Comments- The mass estimate is based on Wang et al. (2022).
References- Ji, Chiappe and Ji, 1999. A new Late Mesozoic confuciusornithid bird from China. Journal of Vertebrate Paleontology. 19(1), 1-7.
Chiappe, Ji, Ji and Norell, 1999. Anatomy and systematics of the Confuciusornithidae (Theropoda: Aves) from the Late Mesozoic of Northeastern China. Bulletin of American Museum of Natural History. 242, 1-89.
Wang, Hu, Zhang, Wang, Zhao, Sullivan and Xu, 2022. A new confuciusornithid bird with a secondary epiphyseal ossification reveals phylogenetic changes in confuciusornithid flight mode. Communications Biology. 5:1398.

Yangavis Wang and Zhou, 2018
Y. confucii Wang and Zhou, 2018
Early Albian, Early Cretaceous
Sihedang, Jiufotang Formation, Liaoning, China
Holotype- (IVPP V18929) (508 g) skull (50.79 mm), mandibles, third to eighth cervical vertebrae, eleven dorsal vertebrae, dorsal ribs, uncinate processes, gastralia, synsacrum, three caudal vertebrae, scapulocoracoids, furcula, sternum (32.09 mm), sternal ribs, humeri (55.38 mm), radii (50.44 mm), ulnae (one proximal; 52.25 mm), pisiform, metacarpals I (8.13 mm), phalanges I-1 (19.31 mm), manual unguals I (11.28 mm), carpometacarpi (28.75 mm), phalanges II-1 (20.10 mm), phalanges II-2 (19.67 mm), manual unguals II (8.54 mm), phalanges III-1 (4.44 mm), phalanges III-2 (11.8 mm), phalanges III-3 (14.63 mm), manual unguals III (9.57 mm), manual claw sheaths, ilia, pubes, ischia, femora (40.06 mm), tibiotarsi (one distal; 50.32 mm), proximal fibula, metatarsal I, phalanx I-1 (6.74 mm), pedal ungual I (7.34 mm), tarsometatarsi (one proximal; 23.17 mm), phalanx II-1 (5.69 mm), phalanx II-2 (9.82 mm), pedal ungual II (7.41 mm), phalanx III-1 (6.85 mm), phalanx III-2 (7.03 mm), phalanx III-3 (7.83 mm), pedal ungual III (7.75 mm), phalanx IV-1 (4.35 mm), phalanx IV-2 (5.11 mm), phalanx IV-3 (4.70 mm), phalanx IV-4 (5.26 mm), pedal ungual IV (7.31 mm), pedal claw sheaths, metatarsal V
Diagnosis- (after Wang and Zhou, 2019) no lateral fossae on dorsal centra; elongate forelimb with a (humerus + ulna)/(femur + tibiotarsus) length ratio 1.19 (compared with 0.91-1.08 in C. sanctus, 1.06 in C. dui, 0.93 in Changchengornis and 0.96 in C. zhengi); manual ungual II not reduced; metatarsal II with dorsal tubercle on lateral surface (centrally located in C. sanctus); hallux more than half length of pedal digit II (less than half in C. sanctus and C. zhengi); pedal ungual I as large as pedal unguals II and IV (smallest in other confuciusornithids); pedal digit III longer than tarsometatarsus (in contrast to other confuciusornithids).
Other diagnoses- Wang and Zhou (2019) listed maxilla with rectangular dorsal process with anteroventral-posterodorsally oriented ridge laterally as a diagnostic character, but the ridge is the maxillary-nasal suture, with the anterodorsal portion making the process rectangular being composed of the nasal.  The labeled nasal (and the bone labeled such in Confuciusornis specimen IVPP V12352 in the same figure) is actually the supraorbital.
Comments- Yangavis was discovered prior to January 2018.  The online version of the description was published on August 4 2018 with a ZooBank reference, making the name valid for that year despite the physical volume not being published until February 2019.  Wang et al. (2022) estimated its mass.
Wang and Zhou (2019) added Yangavis to O'Connor's avialan analysis and recovered it sister to Confuciusornithidae (Confuciusornis plus Changchengornis), with Eoconfuciusornis a more basal confuciusornithiform.
References- Wang and Zhou, 2019 (online 2018). A new confuciusornithid (Aves: Pygostylia) from the Early Cretaceous increases the morphological disparity of the Confuciusornithidae. Zoological Journal of the Linnean Society. 185(2), 417-430.
Wang, Hu, Zhang, Wang, Zhao, Sullivan and Xu, 2022. A new confuciusornithid bird with a secondary epiphyseal ossification reveals phylogenetic changes in confuciusornithid flight mode. Communications Biology. 5:1398.

Zhongornis Gao, Chiappe, Meng, O'Conner, Wang, Cheng and Liu, 2008
Z. haoae Gao, Chiappe, Meng, O'Conner, Wang, Cheng and Liu, 2008
Early Aptian, Early Cretaceous
Dawangzhangzi Beds of Yixian Formation, Liaoning, China
Holotype- (D2455/6) (juvenile male) skull, mandibles, hyoid, nine cervical vertebrae, thirteen dorsal vertebrae, dorsal ribs, gastralia, first sacral vertebra, second sacral vertebra, third sacral vertebrae, anterior fourth sacral vertebra, thirteen caudal vertebrae, chevrons, scapulae (~13.1 mm), incomplete coracoids (~6.5 mm), incomplete furcula, humeri (15.9 mm), radii (13.9 mm), ulnae (14.5 mm), semilunate carpal, metacarpal I (2.8 mm), phalanges I-1 (one fragmentary; 8.1 mm), manual ungual I (4.7 mm), metacarpal II (8.6 mm), phalanges II-1 (one partial; 5.5 mm), phalanx II-2 (7.4 mm), manual ungual II (3.2 mm), metacarpal III (7.7 mm), phalanges III-?2 (one partial; ~5.2 mm), phalanx III-?3 (5.5 mm), manual ungual III (2.9 mm), partial ilia, ischia, femora (15.3 mm), tibiae (20.5 mm), fibula, astragalus, metatarsals I (2.2 mm), phalanges I-1 (1.9 mm), pedal unguals I (1.9 mm), metatarsals II (8.4 mm), phalanges II-1 (2.4 mm), phalanges II-2 (3.4 mm), pedal unguals II (2.7 mm), metatarsals III (9.9 mm), phalanges III-1 (3.2 mm), phalanges III-2 (2.6 mm), phalanges III-3 (3.1 mm), pedal unguals III (2.4 mm), metatarsals IV (9.2 mm), phalanges IV-1 (1.7 mm), phalanges IV-2 (1.7 mm), phalanges IV-3 (1.4 mm), phalanges IV-4 (2.3 mm), pedal unguals IV (2.1 mm), pedal claw sheaths, remiges, retrices
Diagnosis- (after Gao et al., 2008) ancestral manual phalanx III-1 absent or reduced to less than a fifth of the length of III-2.
Other diagnoses- Gao et al. (2008) include several characters in their diagnosis of Zhongornis, whose unique combination was supposed to diagnose it. Of these, the the strut-like coracoid is a pygostylian symplesiomorphy, and the toothless premaxilla and dentary are confuciusornithid symplesiomorphies. The imperforate deltopectoral crest and relative sizes of the manual unguals are plesiomorphic for theropods, while the 13-14 (or ~20 if O'Connor and Sullivan [2014] are right) differentiated caudal vertebrae are a juvenile characteristic (as may be the former two).
Comments- Gao et al. (2008) coded Zhongornis as if it were adult, because they viewed the presence of long remiges and retrices as indications it was close to fledging so that "that developmentally, its skeleton was not very far from maturation." However, juvenile enantiornithines also show well developed remiges, yet lack numerous fusion and morphological characters compared to adults. The resulting analysis found Zhongornis to be sister to Pygostylia. Four characters placed Zhongornis outside Pygostylia. Of these, the unfused distal caudal vertebrae are found in juvenile enantiornithines such as Dalingheornis and IVPP V14238. The presence of more than eight free caudal vertebrae is basically a restatement of the same character. The moderate development of the posterior trochanter might be expected in a juvenile, but juvenile enantiornithines do have large trochanters like adults. Finally, the unfused tibiotarsus is seen in juvenile confuciusornithids and enantiornithines. O'Conner et al. (2009) include Zhongornis in a larger phylogenetic analysis, which they state finds Zhongornis as the sister group of Pygostylia. Yet it's placed sister to Longirostravis in their figure, while DNHM D2567/8 (otherwise unmentioned in this paper, though an actual ?Jiufotang enantiornithine specimen discussed in O'Connor's 2009 thesis) is sister to Pygostylia. This is likely a typo, with Zhongornis and a mistyped DNHM D2522 (later described as Rapaxavis) switched. This is supported by the same four characters as Gao et al. (2008), with the addition of two. The lack of lateral fossae on the dorsal centra is explainable by the increased pneumaticity with age, as shown by the subadult Confuciusornis zhengi holotype which has only slight depressions. Similarly, the relatively robust radius of Zhongornis (~78% of ulnar width) is comparable to C. zhengi (73%) and matched by some juvenile enantiornithines (e.g. GMV-2159's is 82%). The conclusion is that the placement of Zhongornis outside Pygostylia is due entirely to juvenile characters, with only the reduced posterior trochanter not found in other juvenile birds so far.
O'Connor and Sullivan (2014) reevaluated Zhongornis and interpreted the sacrum as having less vertebrae (5-6 instead of 6-7), the tail as having more vertebrae (~20 instead of 13-14), a less elongate coracoid and an ischium without a proximodorsal process (reinterpreted as the ilial peduncle). They believed it to be more similar to scansoriopterygids and oviraptorosaurs than pygostylians, though their analysis still found it to be a basal avialan with scansoriopterygids closer to Aves and oviraptorosaurs less closely related than deinonychosaurs. The stated similarities to scansoriopterygids are ontogenetic (short and deep skull; short humerus; with low flexor tubercles [untrue for scansoriopterygids]) or shared with pygostylians (reduced number of caudal vertebrae in Epidexipteryx [admitted to be absent in Scansoriopteryx]; no distinct transition point or elongated distal caudals [untrue in scansoriopterygids]; 'incipient' pygostyle [untrue in Epidexipteryx, unknown in Scansoriopteryx]; weakly curved manual unguals; no obturator process; penultimate pedal phalanges longest) or more problematic. Of the latter, contra O'Connor and Sullivan, manual phalanx I-1 isn't longer than metacarpal II in Zhongornis (94%) or scansoriopterygids (91% in Scansoriopteryx), and is similar to basal avialans (91% in Balaur; ~92% in Confuciusornis) and basal oviraptorosaurs (~93% in Similicaudipteryx; 89-93% in Caudipteryx). If Zhongornis does lack a proximodorsal ischial process, that would be similar to scansoriopterygids, but the poor preservation proximally and great simiarity in shape to taxa with such processes (e.g. juvenile enantiornithine GMV-2158) make this equivocal at least. The proposed similarities to oviraptorosaurs are also ontogenetic (low number of sacrals; pygostyle 'incipient' if present), shared with pygostylians (concave anterior narial margin formed by premaxilla; long frontals; frontals narrow anteriorly and greatly expanded posteriorly [moreso than oviraptorosaurs]; short tail; robust furcula [untrue in basal oviraptorosaurs]; metacarpal I 33% of metacarpal II length [even stated by the authors to be present in Confuciusornis, and even longer in Changchengornis and Balaur]; metacarpal I wider than metacarpal II [e.g. confuciusornithids, Balaur]; manual phalanx I-1 subequal in length to metacarpal II [see above]; weakly curved manual unguals), or not present in oviraptorosaurs (long nasals) or Zhongornis (robust tail). The presence of ~20 caudal vertebrae is not different from basal pygostylians that lack a pygostyle as e.g. the juvenile Dalingheornis holotype has about 20 caudal vertebrae. Zhongornis has been interpreted as having a reduced manual digit III of three phalanges. As described below, this may not be true, but the similarity to Caudipteryx's two phalanges noted by O'Connor and Sullivan is problematic for two reasons. First, as they state, Sapeornis [and Balaur] has less than four phalanges on digit III. More importantly, the authors are not proposing a caudipterid identification for Zhongornis, and more basal oviraptorosaurs like Protarchaeopteryx and Similicaudipteryx have unreduced digit III. Only the narrowly pointed furcular epicleidia are shared with some oviraptorids and not basal avialans, though the condition in basal oviraptorosaurs is unknown. In conclusion, O'Connor and Sullivan only provide one possible character (no proximodorsal ischial process?) that would make Zhongornis closer to scansoriopterygids, and one that might make it closer to oviraptorosaurs.
If Zhongornis is a juvenile pygostylian, it is likely to be a confuciusornithid (Mortimer, DML 2008). There are four codings in Gao et al.'s matrix which would exclude Zhongornis from Confuciusornithidae. The deltopectoral crest is lower than in adult confuciusornithids, but this is also true of Confuciusornis zhengi . Juvenile enantiornithines also have lower deltopectoral crests than adults. It should also be noted that the crest in Zhongornis is higher and more quadrangular than most Mesozoic pygostylians, which is a character shared with confuciusornithids. Manual ungual II is not smaller than III, which is indeed unlike confuciusornithids and not known to vary with age. Confuciusornithids have a reduced manual phalanx III-1, while Zhongornis was described as having only two long non-ungual phalanges in digit III. Yet the base of digit III is beneath phalanx II-1, so may incorporate a hidden and reduced proximal phalanx as well. Thus the evidence for excluding Zhongornis from Confuciusornithidae due to this character is at worst equivocal, for even if there are only two non-ungual phalanges in digit III, the missing phalanx could be III-1, which would therefore be reduced as in confuciusornithids. Metatarsal I is coded as being straight in Zhongornis, but J-shaped and twisted in confuciusornithids. Yet the photo (figire 4B) suggests it is curved the same amount as in Confuciusornis, while twisting doesn't seem possible to discern in such a poorly preserved element. O'Connor and Sullivan (2014) proposed additional reasons Zhongornis is not a juvenile confuciusornithid. They state it has different manual digital proportions, though do not elaborate. Their earlier statements about metacarpal I length and width, and phalanx I-1 length differing from birds are untrue when it comes to confuciusornithids. The only actual length differences of >5% are phalanx II-1 being 10% shorter in Zhongornis, II-2 being 10% longer, and III-2 being twice as long (all compared to metacarpal II length). As the II-2/II-1 ratio is similar to more basal taxa, it may be a primitive character retained in juveniles. The long III-2 remains unexplained though. Contra O'Connor and Sullivan, the manual unguals do not seem more curved in confuciusornithids than Zhongornis, though they do have larger flexor tubercles, but this may be a juvenile character as muscle/tendon attachment points are often less developed in juveniles. While Zhongornis does differ from Confuciusornis sanctus adults in lacking a humeral fenestra, this is absent in Changchengornis, the subadult C. zhengi, and C. feducciai. Thus this is not an argument against Zhongornis being in the family, and may indeed be ontogenetic. That Zhongornis has more free caudal vertebrae than Confuciusornis is an obvious possible ontogenetic character, with the juvenile enantiornithine Dalingheornis that possesses about 20 free caudal vertebrae and no pygostyle being a potential equivalent. Finally, they note the epicleidia are 'well developed', which would seem to indicate they taper to be slender and pointed. Some Confuciusornis specimens (GMV-2132, Bonn specimen) have pointed ends, though none are as slender as Zhongornis. The enlarged deltopectoral crest, toothless premaxilla and toothless dentary are confuciusornithid synapomorphies. Within Confuciusornithidae, Zhongornis may be referrable to Confuciusornis based on the long humerus (which would become even longer with age), long manual phalanx II-2 compared to II-1 and reduced trochlea on metatarsal IV, but this is hard to determine from such a young specimen where adult morphologies may not be developed yet. For instance, the short snout and absence of a humeral foramen are similar to Changchengornis, but these would also be expected in any juvenile. Manual phalanx II-2 is not bowed as it is in Confuciusornis, but this may be ontogenetic. Confuciusornis is the most common theropod in the Yixian formation, so finding a juvenile example is not unexpected. It is retained as a separate taxon here mainly because ontogeny makes definite referral to Confuciusornis uncertain, and Dawangzhangzi Confuciusornis adults have been reported but not described, so may belong to a new species.
References- Gao, Chiappe, Meng, O'Conner, Wang, Cheng and Liu, 2008. A new basal lineage of Early Cretaceous birds from China and its implications on the evolution of the avian tail. Palaeontology. 51(4), 775-791.
Mortimer, DML 2008. https://web.archive.org/web/20190416181240/http://dml.cmnh.org/2008Jul/msg00256.html
O'Connor, 2009. A systematic review of Enantiornithes (Aves: Ornithothoraces). PhD Thesis. University of Southern California. 586 pp.
O'Conner, Wang, Chiappe, Gao, Meng, Cheng and Liu, 2009. Phylogenetic support for a specialized clade of Cretaceous enantiornithine birds with information from a new species. Journal of Vertebrate Paleontology. 29(1), 188-204.
O'Connor and Sullivan, 2014. Reinterpretation of the Early Cretaceous maniraptoran (Dinosauria: Theropoda) Zhongornis haoae as a scansoriopterygid-like non-avian, and morphological resemblances between scansoriopterygids and basal oviraptorosaurs. Vertebrata PalAsiatica. 52(1), 3-30.

Confuciusornis Hou, Zhou, Gu and Zhang, 1995
= Jinzhouornis Hou, Zhou, Zhang and Gu, 2002
= Eoconfuciusornis Zhang, Zhou and Benton, 2008
Diagnosis- (after Hou et al., 1995) maxilla toothless (unknown in Changchengornis); large foramen in proximal humerus of adults (reversed in C. feducciai).
(after Zhou, 1999) dentary strongly forked posteriorly (unknown in Changchengornis); elongate external mandibular fenestra (unknown in Changchengornis); furcular arm width >20% of arm length (unknown in C. dui).
(after Chiappe et al., 1999) dorsal premaxillary edge straight; manual phalanx II-2 bowed.
(proposed) splenial extends to anterior tip of dentary (unknown in C. dui); trochlea of metatarsal IV much smaller than those of metatarsals II and III.
Other diagnoses- Hou et al. (1995; repeated in Hou, 1997) also included several other characters in their diagnosis. Premaxillary and dentary teeth are now known to be absent in Changchengornis as well, along with the correlated grooves and pits in its beak. Two other derived characters are also now known in Changchengornis- reduced antorbital fenestra; proximal humerus expanded. Most characters used are symplesiomorphies- large orbit; manual ungual I long and robust; manual phalanges slender and unreduced; ischium with proximodorsal process; pedal unguals large and curved; metatarsal V present. Confuciusornis' size is not diagnostic, as C. dui is small while the other three valid species are about equal in size. The semilunate carpal is not unfused to the metacarpals, contra Hou et al.. The robust ischium with "slightly expanded distal end" is a misinterpretation due to the ischium of the paratype being incomplete distally.
Zhou (1999) includes numerous additional characters in his diagnosis, most of them symplesiomorphies of Pygostylia- postorbital robust, Y-shaped and contacts jugal and squamosal; dorsal process of maxilla and nasal separating naris and antorbital fenestra; quadratojugal with slender dorsal process; small, rounded posterior surangular foramen; deep lateral fossae in dorsal centra; gastralia present; seven to nine sacral vertebrae; pygostyle composed of eight to nine vertebrae; coracoid short; sternal keel not pronounced; furcula lacking hypocleidium; humerus slightly longer than ulna; semilunate carpal fused to metacarpal II; metscarpal III subequal in length to II; metacarpal III reduced in width, especially proximally; phalangeal formula of manus 2-3-4; manual ungual III large; manual digits II and III subequal in length; fibula not reaching distal end of tibiotarsus. Three are derived characters now known to be shared with Changchengornis and other confucisornithids- fused scapulocoracoid; manual ungual II reduced; manual phalanx III-1 short. The Y-shaped quadratojugal seems to vary between specimens. Finally, two characters are too vague to evaluate- quadrate high without orbital process developed; pisiform slender.
Chiappe et al. (1999) include a "straight culmen and mandible" in their diagnosis, though technically the culmen (upper beak edge) is concave in the rare case the keratinous beak is preserved (e.g. C. dui holotype). Still, the straight dorsal premaxillary edge is unique. The straight mandible is plesiomorphic, however. The notched anteromedian margin of the premaxillae is seen in more basal taxa as well, but is less obvious there due to a lack of fused premaxillae, so is not a diagnostic character. The retinaculi extensoris tubercle on the anterodistal tibiotarsus is a pygostylian synplesiomorphy. The hallux length is variable in Confuciusornis and can be as long as in Changchengornis (e.g. IVPP V11308).
Zhou and Hou (2002) largely reuse Zhou's (1999) diagnosis, but further specify the sacrum has seven vertebrae (as in other basal avebrevicaudans), the fibula is ~75% of tibiotarsal length (though it is comparable in length in IVPP V11552 and Changchengornis and overlaps other avialans' lengths), and metatarsal V is about a third as long as the tarsometatarsus (shared with Changchengornis).
References- Hou, Zhou, Gu and Zhang, 1995. Confuciusornis sanctus, a new Late Jurassic sauriurine bird from China. Chinese Science Bulletin. 40(18), 1545-1551.
Hou, 1997. Mesozoic birds of China. Taiwan Provincial Feng Huang Ku Bird Park. Taiwan: Nan Tou, 228 pp.
Chiappe, Ji, Ji and Norell, 1999. Anatomy and systematics of the Confuciusornithidae (Theropoda: Aves) from the Late Mesozoic of Northeastern China. Bulletin of American Museum of Natural History. 242, 1-89.
Zhou, 1999. Early evolution of birds and avian flight-evidence from Mesozoic fossils and modern birds. PhD Dissertation, Department of Systematics and Ecology, University of Kansas. 216 pp.
Hou, Zhou, Zhang and Gu, 2002. Mesozoic birds from western Liaoning in China. Liaoning, China: Liaoning Science and Technology Publishing. ISBN 7-5381-3392-5. 120 pp.
Zhou and Hou, 2002. The Discovery and Study of Mesozoic Birds in China. in Chiappe and Witmer, (eds.). Mesozoic Birds- Above the Heads of Dinosaurs. University of California Press, Berkeley, Los Angeles, London. 160-183.
Zhang, Zhou and Benton, 2008. A primitive confuciusornithid bird from China and its implications for early avian flight. Science in China Series D: Earth Sciences. 51(5), 625-639.
C? chuonzhous Hou, 1997
Late Barremian-Early Aptian, Early Cretaceous
Jianshangou Beds of Yixian Formation, Liaoning, China
Holotype- (IVPP V10919; paratype of Confuciusornis sanctus) distal tibiotarsus, fibular fragment(?), metatarsal I, phalanx I-1, incomplete pedal ungual I, tarsometatarsus (distal metatarsal II missing; 33 mm), phalanx II-1, distal phalanx II-2, pedal ungual II, phalanx III-1, phalanx III-3, pedal ungual III, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, pedal claw sheaths, body feathers
Diagnosis- indeterminate within Confuciusornis.
Other diagnoses- Hou (1997) listed many problematic characters in his diagnosis. It is not larger than C. sanctus specimens, though it is larger than most. Contra Hou, the tibiotarsus is within the range of robusticity of C. sanctus specimens. Hou cites the tibiotarsal width as 4 mm and the metatarsal length of 33 mm (ratio of 12.1%), compared to the C. sanctus paratype's 2.5 mm and 22 mm respectively (ratio of 11.4%), but C. sanctus specimen GMV-2133 has a ratio of 18.2%. The tibiotarsus is said to be anteroposteriorly thick, but measurements are not cited, and this would be difficult to determine in a specimen which is crushed in anterior view. Contra Hou, the tibiotarsus is clearly expanded distally, as in C. sanctus. The supposedly unfused proximal tarsals (also noted by Zhou, 1995) were found to be only equivocally present by Chiappe et al. (1999), and as noted by them, could be ontogenetic in any case. Based on the photo, the tibiotarsus is much too poorly preserved to determine much structure. Hou lists pedal ungual I's small size and large degree of curvature (a typo for a small degree of curvature, as seen by the description and illustration) as being diagnostic, but the description also mentions digit I having three phalanges. Chiappe et al. believed Hou mistook metatarsal I for another phalanx, but he actually mistook the broken proximal portion of pedal ungual I as another phalanx. This is apparent from photos, his figure and the description, which states the supposed phalanx I-2 is extremely short. It would also explain the ungual's small size and lack of curvature, as only the distal end was interpreted as the ungual by Hou. Finally, Hou lists "metatarsal V is present and is isolated, except for its articulated proximal end", but it is present in C. sanctus as well. The discussion indicates it is metatarsal V's robusticity and lack of fusion with the tarsometatarsus that Hou belives is unique. Examination of photos leads me to believe that what's identified as metatarsal V is actually a broken proximal end of metatarsal II. This would explain why the metatarsus is so narrow, and why metatarsals I and V are on the same side. The discussion adds a couple additional characters supposedly distinguishing C. chuonzhous from C. sanctus. The distal tibiotarsal condyles are said to be inconspicuous and not anteriorly projected, but as noted above, the tibiotarsus is far too poorly preserved to judge this. It is said to have probably possessed at least two distal tarsals, while C. sanctus is described as having only one. Yet C. sanctus has its distal tarsals fused to the metatarsus (the single tarsal identified in a paratype by Hou is probably part of the astragalar condyles), while Hou earlier says distortion makes it hard to assess the presence of distal tarsals in C. chuonzhous, but that he assumes they were unfused based on the specimen's primitive morphology, and were perhaps not preserved! The photo shows no evidence for free tarsals, the structure representing such in the illustration being the proximal end of metatarsal III.
Comments- This specimen was initially listed as a paratype of C. sanctus by Hou et al. (1995a,b), though it was not illustrated and was mistyped as IVPP V10915 in the measurements paragraph of their later paper (1995b). Hou et al. (1995b) noted the fibula extended to near the distal end of the tibiotarsus, ending in an expansion. This may merely be part of the tibiotarsus, however, and was not mentioned or illustrated by Hou (1997). Hou (1997) erected the species C. chuonzhous for it (erroneously called Confuciusornis meidus in the English summary), based on a number of problematic characters (see above). Chiappe agreed Hou's characters were inadequate and synonymized C. chuonzhous with C. sanctus. Yet the specimen is too fragmentary to determine if it has pedal characters of Confuciusornis as opposed to Changchengornis (distally unfused metatarsals III and IV; metatarsal IV trochlea reduced in size), and Confuciusornis species cannot be distinguished by tibiotarsal or pedal characters yet. The large size and horizon do suggest either C. sanctus or C. feducciai, but it must remain indeterminate within Confuciusornis.
References- Hou, Zhou, Gu and Zhang, 1995a. Confuciusornis sanctus, a new Late Jurassic sauriurine bird from China. Chinese Science Bulletin. 40(18), 1545-1551.
Hou, Zhou, Martin and Feduccia, 1995b. A beaked bird from the Jurassic of China. Nature. 377, 616-618.
Zhou, 1995. New understanding of the evolution of the limb and girdle elements in early birds - Evidences from Chinese fossils. In Sun and Wang (eds). Sixth Symposium on Mesozoic Terrestrial Ecosystems and Biota, short papers. Beijing: China Ocean Press. 209-214.
Hou, 1997. Mesozoic birds of China. Taiwan Provincial Feng Huang Ku Bird Park. Taiwan: Nan Tou, 228 pp.
Chiappe, Ji, Ji and Norell, 1999. Anatomy and systematics of the Confuciusornithidae (Theropoda: Aves) from the Late Mesozoic of Northeastern China. Bulletin of American Museum of Natural History. 242, 1-89.
C. dui Hou, Martin, Zhou, Feduccia and Zhang, 1999
Late Barremian-Early Aptian, Early Cretaceous
Jianshangou Beds of Yixian Formation, Liaoning, China
Holotype- (IVPP V11553; lost) (male adult) skull (39.31 mm), horny beak, mandible (40 mm), sclerotic ring, hyoid, cervical vertebrae, dorsal vertebrae, dorsal ribs, gastralia, sacrum, caudal vertebrae, pygostyle (21.20 mm), scapula (34.59 mm), sternum, humeri (40.97 mm), radii (33.95 mm), ulnae (34.07 mm), metacarpal I (7.03 mm), phalanx I-1 (15.66 mm), manual ungual I (8.19 mm), carpometacarpi (mcII 19.70, mcIII 14.06 mm), phalanx II-1, phalanx II-2 (15.88 mm), manual ungual II, phalanx III-1 (3.20 mm), phalanges III-2 (8.73 mm), phalanges III-3 (11.04 mm), manual unguals III (8.17 mm), ilium, femora (35.48 mm), tibiotarsi (40.41 mm), metatarsal I, phalanx I-1, pedal ungual I (3.37 mm), tarsometatarsi (mtII 17.16, mtIII 19.50, mtIV 18.20 mm), phalanges II-1 (5.07 mm), phalanx II-2 (5.37 mm), pedal ungual II, phalanges III-1 (4.43 mm), phalanges III-2 (4.13 mm), phalanges III-3 (4.97 mm), pedal ungual III, phalanges IV-1, phalanges IV-2, phalanges IV-3 (3.25 mm), phalanges IV-4, pedal ungual IV, body feathers, remiges, retrices
Paratype- ?(IVPP V11521) (217 g; <1 year old subadult) including vertebrae, ribs, caudal vertebrae, pygostyle, incomplete scapulocoracoid, furcula, sternum, eight sternal ribs, humeri (42.00 mm), radius (38.16 mm), ulna (39.00 mm), carpometacarpus (19.00 mm), pelvis, femora (36.00 mm), tibiotarsus (41.00 mm) and tarsometatarsus (19.50 mm)
Referred- ?(CYCYB235) (male) specimen including humerus (35.43 mm), radius (29.47 mm), ulna (29.68 mm), femur (31.66 mm), tibiotarsus (36.25 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
Diagnosis- (after Hou et al., 1999) small size (femur <40 mm in adults) (also in Changchengornis); manual unguals I and III subequal in size.
(proposed) narrow, tapered and vertical ascending process of maxilla without maxillary fenestra; maxilla takes up most of ventral orbital margin; low rounded dorsal jugal process(?); jugal forms ventral margin of laterotemporal fenestra(?); posterodorsal dentary process extends posteriorly over most of mandibular fenestra; posterodorsal dentary process taller than posteroventral process; sternal lateral processes not bifurcate; sternal ribs attach to lateral processes; sternal ribs grow posteriorly shorter, so that last is less than a third as long as the first; last two sternal ribs markedly expanded distally; metacarpal I tapers proximally; tibiotarsofemoral ratio 84% the size of C. sanctus specimens of similar length.
Other diagnoses- The lack of a ventral expansion on the anterior dentary was also cited by Hou et al. (1999) in their diagnosis, but this is a symplesiomorphy compared to C. sanctus and C. feducciai. Contra Hou et al., the premaxilla does not appear to be more pointed anteriorly than C. sanctus. Similarly, the sternum elongation (~74%) falls within the range of variation in C. sanctus (e.g. ~75% in GMV-2131). Some C. sanctus are known to have an anterior notch in their sterna (e.g. IVPP V10928, V13313) as does C. feducciai. Short posterolateral sternal processes are also present in C. sanctus and C. feducciai, so this is not diagnostic of the species either. Finally, the tarsometatarsus is not shorter than in C. sanctus, as the tarsometatarsofemoral ratio is 56%, while C. sanctus' varies from 53-61%.
Comments- Marug�n-Lob�n et al. (2011) stated "the holotype is apparently lost" although a cast exists in the IVPP collections.  Chiappe et al. (2008) notes that C. dui is an outlier on plots of limb bone lengths compared to 108 specimens of C. sanctus. This is most obvious in the tibiotarsofemoral plots, where a similarly sized C. sanctus would have a tibiotarsus 48.7 mm long instead of C. dui's 41 mm. Marugan-Lobon et al. conclude "Overall, the holotype of C. dui is quantitatively indistinguishable from the small end of the spectrum of C. sanctus, although a restudy of the former and of the referred material (Hou et al. 1999) needs to be done before regarding these species as synonymous."  Navalon et al. (2018) provide measurements of the holotype. 
Wu et al. (2021b) notes that although IVPP V11521 "was originally described as the paratype of Confuciusornis dui (Hou et al., 1999), this referral is unsupported since V 11521 preserved none of the elements on which the diagnosis of this species is based nor is it small in size compared to other specimens of Confuciusornis."  They "consider this specimen to be most likely C. sanctus but to be conservative we refer the specimen to Confuciusornis indet."  Notably all of the elements have been prepared from the sediment and the specimen has been used to study histology and cartilage in Confuciusornis (Bailleul and Zhou, 2021; Wu et al., 2021a, b).  Wang et al. (2022) provided measurements from "a high-resolution image."
Marugan-Lobon and Chiappe (2022) listed CYCYB235 in their table as "C. dui?)".
References- Hou, Martin, Zhou, Feduccia and Zhang, 1999. A diapsid skull in a new species of the primitive bird Confuciusornis. Nature. 399, 679-682.
Chiappe, Marugan-Lobon, Ji and Zhou, 2008. Life history of a basal bird: morphometrics of the Early Cretaceous Confuciusornis. Biology Letters. 4(6), 719-723.
Marug�n-Lob�n, Chiappe, Ji, Zhou, Gao, Hu and Meng, 2011 (online 2010). Quantitative patterns of morphological variation in the appendicular skeleton of the Early Cretaceous bird Confuciusornis. Journal of Systematic Palaeontology. 9(1), 91-101.
Naval�n, Meng, Marug�n-Lob�n, Zhang, Wang, Xing, Liu and Chiappe, 2018 (online 2017). Diversity and evolution of the Confuciusornithidae: Evidence from a new 131-million-year-old specimen from the Huajiying Formation in NE China. Journal of Asian Earth Sciences. 152, 12-22.
Bailleul and Zhou, 2021. SEM analyses of fossilized chondrocytes in the extinct birds Yanornis and Confuciusornis: Insights on taphonomy and modes of preservation in the Jehol biota. Frontiers in Earth Science. 9, 718588.
Wu, Bailleul, Li, O'Connor and Zhou, 2021a. Osteohistology of the scapulocoracoid of Confuciusornis and preliminary analysis of the shoulder joint in Aves. Frontiers in Earth Science. 9, 617124.
Wu, O'Connor, Li and Bailleul, 2021b. Cartilage on the furculae of living birds and the extinct bird Confuciusornis: A preliminary analysis and implications for flight style inferences in Mesozoic birds. Vertebrata PalAsiatica. 59(2), 106-124.
Marugan-Lobon and Chiappe, 2022. Ontogenetic niche shifts in the Mesozoic bird Confuciusornis sanctus. Current Biology. 32(7), 1629-1634.
Wang, Hu, Zhang, Wang, Zhao, Sullivan and Xu, 2022. A new confuciusornithid bird with a secondary epiphyseal ossification reveals phylogenetic changes in confuciusornithid flight mode. Communications Biology. 5:1398.
C. jianchangensis Li, Wang and Hou, 2010
Early Albian, Early Cretaceous
Jiufotang Formation, Liaoning, China
Holotype- (PMOL-AM00114) skull (~39 mm), mandibles, twelve cervical vertebrae, nine dorsal vertebrae, two dorsal ribs, gastralia, sacrum, three caudal vertebrae, chevron, pygostyle (27.2 mm), ilium (31 mm), pubes (~36 mm), ischium (~22 mm), femora (42 mm), tibiotarsi (47 mm), fibulae (15 mm), tarsometatarsi (II 20.5, III 21.3, IV ~19 mm), metatarsal I (4.5 mm), phalanges I-1 (4.7 mm), pedal unguals I (3.8 mm), phalanx II-2 (5.5 mm), phalanges III-1 (6 mm), phalanx III-2 (4.6 mm), phalanx III-3 (5.8 mm), pedal ungual III (7.2 mm), phalanx IV-1 (4.5 mm), phalanx IV-2 (3.2 mm), phalanx IV-3 (3.8 mm), phalanx IV-4 (4.3 mm), pedal ungual IV (6.7 mm)
Comments- While Li et al. (2010) described this as a new species of Confuciusornis, Cau (2010, online) suggested it possesses several characters suggesting a closer relationship with ornithothoracines. These include the small number of dorsal vertebrae, ischium elongate compared to pubis, no prominent proximodorsal ischial process, wide mid dorsal ischial process, reduced fibula and metatarsal V absent. Cau's unpublished analysis found it in a trichotomy with enantiornithes and euornithines. However, better photos in Wang et al. (2019) suggest misinterpretations by Li et al..  In particular, the position of hypapophyses in the presacral column suggests eight post-atlantal cervicals and fourteen dorsals instead of twelve and nine respectively.  The ischium was figured incorrectly by Li et al. as having a long and low mid dorsal process, but actually has a tall proximodorsal process just right of the posterior sacrum while the dorsal edge distal to that is broken.  The ischium is 61% of pubic length, not 73% as listed in their measurements table.  The supposed fibulae would have their distal ends overlain by the tibiae if they aren't merely shattered pieces of tibia themselves.  Finally, metatarsal V is often hidden or missing in Confuciusornis specimens as noted by Wang et al..  Whether it is synonymous with C. sanctus as suggested by Wang et al. requires further analysis.
References- Cau, online 2010. http://theropoda.blogspot.com/2010/09/confuciusornis-jianchangensis-e-un.html
Li, Wang and Hou, 2010. A new species of Confuciusornis from Lower Cretaceous of Jianchang, Liaoning, China. Global Geology. 29(2), 183-187.
Wang, O'Connor and Zhou, 2019 (online 2018). A taxonomical revision of the Confuciusornithiformes (Aves: Pygostylia). Vertebrata PalAsiatica. 57(1), 1-37.
C. feducciai Zhang, Gao, Meng, Liu, Hou and Zheng, 2009
Late Barremian-Early Aptian, Early Cretaceous
Jianshangou Beds of Yixian Formation, Liaoning, China
Holotype- (D2454) (adult male) skull, mandibles, atlas, axis, six cervical vertebrae, eleven dorsal vertebrae, eight pairs of dorsal ribs, six uncinate processes, gastralia, synsacrum, five caudal vertebrae, pygostyle (~27 mm), scapula, coracoids, furcula, sternum, four sternal ribs, humeri (78.09 mm), radii, ulnae (69.96 mm), pisiform, metacarpal I, phalanges I-1, manual unguals I, carpometacarpi (32 mm), phalanges II-1, phalanges II-2, manual unguals II, phalanx III-1, phalanx III-2, phalanx III-3, manual ungual III, ilia, pubes, ischia, femora (58.49 mm), tibiotarsi (68.87 mm), fibula, metatarsals I, phalanges I-1, pedal unguals I, tarsometatarsi (33.5 mm), phalanx II-1, phalanx II-2, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal phalanges, pedal unguals, metatarsal V, body feathers, retrices
Diagnosis- (after Zhang et al., 2009) elongate forelimb (humerus+ulna / femur+tibia >110%); foramen absent in deltopectoral crest of humerus (also in Changchengornis); manual phalanx I-1 reduced to be subequal in width to III-3; ischium >50% of pubic length.
(proposed) anterior dentary expanded ventrally (also in C. sanctus); anterolateral sternal processes present; posterolateral sternal processes elongate and directed anterolaterally.
Other diagnoses- Zhang et al. (2009) also included the V-shaped furcula in their diagnosis, but this is seen in some C. sanctus specimens as well (e.g. GMV-2132). They also used the character "sternum broader than long", but is it actually comparable to C. sanctus when the lateral processes are ignored. The deltopectoral crest has the same rectangular shape in Changchengornis and some C. sanctus as well (e.g. Jinzhouornis yixianensis holotype). Large size is not a diagnostic character of the species, as there are larger C. sanctus individuals known (e.g. BSP 1999 I 15). Although Zhang et al. state manual ungual I is "nearly as large" as manual ungual III, unlike C. sanctus, III is 77% as large as I. This is comparable to the ratio of 73% found in C. sanctus and quite unlike the 104% ratio in C. dui.
Comments- The holotype of C. feducciai was used in Chiappe et al.'s (2008) morphometric study as an example of C. sanctus, though it was an outlier in the humerofemoral and ulnofemoral plots in their figure 2. Is it possible that C. feducciai is merely an exceptionally large and ossified individual of C. sanctus? The data seem to argue against this. The sternal characters could easily be due to extra ossification with growth. Yet Confuciusornis seems to gain its humeral foramen with adulthood, and reducing the robusticity of manual digit I with age seems counterintuitive. Furthermore, the forelimb is longer than even comparably sized C. sanctus (e.g. BSP 1999 I 15, GMV-59-1, 2132, IVPP V11370), showing it's not merely the continuation of an allometric trend. The ischiopubic ratio is unknown to vary with age in theropods. The elongate sternal processes, gracile digit I and elongate ischium are actually more similar to ornithothoracines than confuciusornithids, but there are at least ten confuciusornithid characters which argue for its placement in the family.
C. feducciai may be more closely related to C. sanctus than to C. dui based on the ventrally expanded anterior dentary, though the lack of a deltopectoral foramen argues it is outside the sanctus + dui clade.
References- Chiappe, Marugan-Lobon, Ji and Zhou, 2008. Life history of a basal bird: morphometrics of the Early Cretaceous Confuciusornis. Biology Letters. 4(6), 719-723.
Zhang, Gao, Meng, Liu, Hou and Zheng, 2009. Diversification in an Early Cretaceous avian genus: evidence from a new species of Confuciusornis from China. Journal of Ornithology. 150(4), 783-790.
Marug�n-Lob�n, Chiappe, Ji, Zhou, Gao, Hu and Meng, 2011 (online 2010). Quantitative patterns of morphological variation in the appendicular skeleton of the Early Cretaceous bird Confuciusornis. Journal of Systematic Palaeontology. 9(1), 91-101.
C. zhengi (Zhang, Zhou and Benton, 2008) new comb.
= Eoconfuciusornis zhengi Zhang, Zhou and Benton, 2008
Hauterivian, Early Cretaceous
Sichakou, Huajiying Formation, Hebei, China
Holotype- (IVPP V11977; holotype of Eoconfuciusornis zhengi) (207 or 220 g, subadult male) skull (42.43 mm), mandibles (35 mm), keratinous beak, hyoids, atlas, axis, cervical vertebrae 3-7, cervical ribs, twelve to fourteen dorsal vertebrae, dorsal ribs, uncinate processes, gastralia, first sacral vertebra, second sacral vertebra, fused third to fifth sacral vertebrae, sixth sacral vertebra, seventh sacral vertebra, eight caudal vertebrae, pygostyle (24.85 mm), scapulae (27 mm), coracoid, furcula, sternum, humeri (one incomplete; 39.69 mm), radii (one partial; 32.77 mm), ulnae (one partial; 35.21 mm), scapholunare, pisiform, semilunate carpal, metacarpal I (6.29 mm), phalanx I-1 (16.23 mm), manual ungual I (8.89 mm), metacarpal II (19.12 mm), phalanges II-1 (one proximal; 15.36 mm), phalanx II-2 (15.81 mm), manual ungual II (3.58 mm), metacarpals III (one distal; 16.22 mm), phalanges III-1 (3.00, 3.11 mm), phalanges III-2 (one proximal; 9.62, 9.63 mm), phalanx III-3 (11.04, 7.89 mm), manual ungual III (5.15 mm), incomplete ilia, distal pubes (29 mm), ischium, femora (37.33, 35.53 mm), tibiae (44.34, 43.49 mm), fibulae, astragali, metatarsals I (4.09, 4.18 mm), phalanges I-1 (3.56, 3.96 mm), pedal unguals I (3.78, 4.04 mm), tarsometatarsi (mtII 20.38, 18.85 mm; mtIII 22.28 mm; mtIV 20.70 mm), phalanges II-1 (4.91, 5.06 mm), phalanges II-2 (6.87, 6.15 mm), pedal unguals II (5.90, 6.05 mm), phalanges III-1 (6.23, 6.15 mm), phalanges III-2 (4.59, 4.96 mm), phalanges III-3 (4.74, 5.71 mm), pedal unguals III (4.68 mm), phalanges IV-1 (3.59, 3.54 mm), phalanges IV-2 (3.03, 2.77 mm), phalanges IV-3 (2.83, 2.55 mm), phalanges IV-4 (4.09, 4.22 mm), pedal unguals IV (4.27 mm), body feathers, remiges, retrices
Referred- (BMNHC-PH870) (male) skull (46.52 mm), mandibles, two cervical vertebrae, few dorsal vertebrae, dorsal ribs, gastralia, synsacrum, several caudal vertebrae, pygostyle (25.50 mm), scapulocoracoid (coracoid 14.44 mm), furcula, humeri (46.65, 46.47 mm), radii (36.40, 40.41 mm), pisiforms?, metacarpals I (one proximal; 7.36 mm), phalanges I-1 (17.87 mm), manual unguals I (9.41 mm), carpometacarpi (mcII 24.15, mcIII 22.77 mm), phalanges II-1 (17.12 mm), phalanges II-2 (18.65 mm), manual unguals II (4.70 mm), phalanx III-1, phalanges III-2, phalanges III-3 (12.75 mm), manual unguals III (7.04 mm), manual claw sheaths, femora (40.97 mm), tibiotarsus (51.84 mm), metatarsals I (5.24, 5.41 mm), phalanx I-1 (3.57 mm), pedal ungual I, tarsometatarsi (mtII 21.68, 22.21 mm; mtIII 24.77, 25.68 mm; mtIV 23.61 mm), phalanges II-1 (one proximal; 4.83 mm), phalanges II-2 (one distal; 6.60 mm), pedal unguals II (5.81 mm), phalanges III-1 (6.27 mm), phalanges III-2 (4.99, 6.10 mm), phalanges III-3 (5.12, 5.90 mm), pedal unguals III (6.93 mm), phalanges IV-1 (4.28, 3.91 mm), phalanges IV-2 (2.95, 4.10 mm), phalanges IV-3 (3.02 mm), phalanges IV-4 (3.64 mm), pedal unguals IV (5.47 mm), pedal claw sheaths, body feathers, remiges, retrices (Naval�n, Meng, Marug�n-Lob�n, Zhang, Wang, Xing, Liu and Chiappe, 2018)
(STM 7-144) (adult female) skull, sclerotic plates, mandible, hyoid, ~seven-eight cervical vertebrae, ~eleven dorsal vertebrae, dorsal ribs, four uncinate processes, gastralia, synsacrum, five caudal vertebrae, incomplete pygostyle, scapulae, coracoid fragments, furcular fragments, sternum, sternal ribs, humeri (32.9, 33.81 mm), radii (26.5, 26.11 mm), ulnae (26.51 mm), pisiform, proximal carpal, metacarpal I (5.8 mm), phalanx I-1 (11.7, ~9.2 mm), manual ungual I (6.4 mm), carpometacarpi (15.9 mm; mcII 14, mcIII 14, 13.11 mm), phalanges II-1 (10.6 mm), phalanges II-2 (10 mm), manual unguals II (~3, 3.51 mm), phalanx III-1 (2.81 mm), phalanx III-2 (~5.3 mm), phalanx III-3 (~7.8 mm), manual ungual III (4.31 mm), manual claw sheath, ilial fragment, pubes (one distal; ~23.7 mm), ischia (14.4, 14.4 mm), femora (25.4 mm), tibiotarsi (33.8, 34.2 mm), metatarsal I, phalanx I-1, pedal ungual I, tarsometatarsi (19.1, 19.2 mm), phalanx II/III-?, phalanx II-2/III-3, pedal ungual II/III, phalanx III-1, proximal phalanx III-2, phalanx IV-1, ovarian follicles, propatagia, postpatagia, body feathers and remiges (O'Connor et al., 2015)
Diagnosis- (after Zhang et al., 2008) dorsal vertebral centra lacking deep lateral fossae (ontogenetic?; unknown in C. feducciai); acromion process short (ontogenetic?); coracoid proximodistally short; extensor canal of astragalus bridged over (unknown in C. feducciai).
(proposed) enlarged surangular foramen (also in C. sanctus; unknown in C. feducciai); procoelous caudal centra (also in Zhongjianornis); semilunate dorsal condyle of ulna (also in Anchiornis and Zhongjianornis).
Other diagnoses- Zhang et al. (2008) included additional humeral characters in their diagnosis, most of which are viewed below as ontogenetic (low deltopectoral crest on humerus; the redundant proximal end of humerus expanded less than twice the width of distal end; humerus lacks deltopectoral foramen). They also used the elongate tarsometatarsus (53% of tibial length) as a distinguishing character, but the unfused astragalus would subtract another percent or two (it's 1.7 mm deep), and juveniles have longer lower limb elements. In any case, it is not that different from the 47-49% found in Confuciusornis sanctus, well within the range of individual variation.
Comments- Jin et al. (2008) note the bird-bearing beds at Sichakou are the Huajiying Formation, which is above the Dabeigou Formation (contra Zhang et al., 2008).
A large number of characters suggest the holotype is a subadult. These include a small size, course ends of long bones, poorly fused premaxillae, unfused dentaries, unfused cervical ribs, unfused anterior and posterior sacral vertebrae, apparently unossified uncinate processes and sternal ribs, largely unossified sternum, unfused carpometacarpus, tarsus not fused to tibia, and poorly fused metatarsus, in addition to the characters mentioned below. Zhang et al. argue zhengi is nearly an adult based on its supposedly medium size and elongate retrices. Yet the humerus is 40 mm long, which is shorter than any of the 106 specimens examined by Chiappe et al. (2008), even if Zhang et al. do cite one specimen which is smaller (IVPP V10928). It's also quite possible C. zhengi was a bit larger as an adult than C. sanctus. Similarly, juvenile enantiornithines like GMV-2159, Jibeinia and Protopteryx have elongate retrices. Zheng et al. (2017) noted the length of the sternal stain is much greater than STM 7-144's sternum, suggesting "the stain includes more than the sternum or does not represent the sternum at all."  They also find "Uncinate processes were not reported in IVPP V11977 however they are present, misidentified as displaced gastralia (J. O’C. pers. obs.)."
O'Connor et al. (2015) first mention collagen bands "in a referred specimen of the confuciusornithiform Eoconfuciusornis zhengi Zhang et al., 2008 (STM7-144; J.K.O'C., pers. observ.)", which was later briefly described by Zheng et al. (2017).  The latter referred it to Eoconfuciusornis based on provenance, as well as finding "the deltopectoral crest of the humerus is proportionately smaller than in other confuciusornithiforms and the tarsometatarsus is slightly longer than half the tibiotarsus", and "STM7-144 differs from other known confuciusornithiforms but resembles E. zhengi IVPP V119177 in that the absence of a fenestra in the deltopectoral crest of the humerus and proportionately smaller premaxillary corpus."  They noted it was more mature based on the sternal ossification, carpometacarpus fusion and tarsometatarsus fusion, but was also about 85% the size.  While the authors stated "observed differences between the two specimens could reflect ontogenetic changes, sexual dimorphism, and or taxonomic diversity; due to this uncertainty we refer STM7-144 to Eoconfuciusornis indet., it is referred to zhengi here with size differences at maturity considered individual variation as in e.g. Balaur.
Navalon et al. (2018) describe a new specimen from the same beds, BMNHC-PH870, which was reported to differ from the holotype in a lower interclavicular angle (~65 vs. ~78 degrees), more elongate coracoid (probably due to perspective), longer and taller deltopectoral crest, deltopectoral foramen, fused scapulocoracoid, fused carpometacarpus, and fused tibiotarsus.  The latter four, lower interclavicular angle (e.g. juvenile enantiornithies) and taller deltopectoral crest are plausibly ontogenetic and while the authors claim "there is no evidence indicating that juvenile specimens of C. sanctus lacked humeral fenestration and our data do not show any ontogenetic widening of this structure in this species", my identification of Zhongornis as a juvenile Confuciusornis would contradict this.  Similarly, while they say "the morphology of the humerus in BMNHC-PH870 is clearly different from that of E. zhengi", the two group separately from C. sanctus in their Figure 6C and closer to each other than the morphospace variation within C. sanctus.  Navalon et al. conclude "BMNHC-PH870 is morphologically most similar to the coeval Eoconfuciusornis zhengi" but only place it in Confuciusornithidae, whereas here it is referred to that species.
A stem-confuciusornithid?- Zhang et al. (2008) described Eoconfuciusornis zhengi as basal to Changchengornis and Confuciusornis based on several characters. Of these, the poor development of the lateral dorsal central fossae is probably ontogenetic, as pneumaticity increases with age in saurischians. Even if it is characteristic of adults as well, it would more parsimoniously be an apomorphy, since Sapeornis and ornithothoracines both have deep fossae like Confuciusornis and Changchengornis. The low acromion is similarly perhaps caused by ontogeny, as that of the juvenile Zhongornis is similar. Again, this would be just as likely to be an apomorphy of zhengi, since ornithothoracines have prominent acromions like Confuciusornis and Changchengornis. The short coracoid is more likely to be an apomorphy, since Shenzhouraptor, Jixiangornis and some Sapeornis specimens have elongate coracoids. The coracoid foramen is not known to be absent in Changchengornis, so its absence remains an apomorphy of Confuciusornis sanctus. The pubic boot is not known to be absent in Changchengornis. The low deltopectoral crest may be ontogenetic, as this is true in enantiornithines. The elongate astragalar ascending process is found in all coelurosaurs, and is only not apparent in Confuciusornis and Changchengornis because of their completely fused tibiotarsi. The lack of fusion in zhengi is ontogenetic, as more basal avialans have tibiotarsi. Additional characters are listed in the text as differing from other confuciusornithids, including some that could be attributed to ontogeny (hypocleidial swelling absent; poorly ossified sternum) and which are within the range of variation of Confuciusornis (ventral tubercle of humerus not pointed- GMV-2132).
Contrary to this hypothesis, I believe zhengi is more closely related to Confuciusornis than either is to Changchengornis. This is based on the enlarged surangular foramen, furcular arm width which is >20% of arm length, and bowed manual phalanx II-2. In fact, the first character is only found in C. sanctus, not C. dui. The only character which would place zhengi outside Confuciusornis (sanctus + dui) is the absent humeral foramen, but this may be ontogenetic and seems to be developing as a fossa in the specimen. The dorsal maxillary process appears narrow and vertical in the figure, as in C. dui, but Zhang et al. note this may be the anterior margin of a broader process instead. It seems more parsimonious to place Eoconfuciusornis zhengi within Confuciusornis as C. zhengi, unless C. dui is to be assigned its own genus.
References- Chiappe, Marugan-Lobon, Ji and Zhou, 2008. Life history of a basal bird: Morphometrics of the Early Cretaceous Confuciusornis. Biology Letters. 4(6), 719-723.
Jin, Zhang, Li, Zhang, Li and Zhou, 2008. On the horizon of Protopteryx and the early vertebrate fossil assemblages of the Jehol Biota. Chinese Science Bulletin. 53(18), 2820-2827.
Zhang, Zhou and Benton, 2008. A primitive confuciusornithid bird from China and its implications for early avian flight. Science in China Series D: Earth Sciences. 51(5), 625-639.
O'Connor, Li, Lamanna, Wang, Harris, Atterholt and You, 2015. A new Early Cretaceous enantiornithine (Aves, Ornithothoraces) from northwestern China with elaborate tail ornamentation. Journal of Vertebrate Paleontology. 36(1), e1054035.
Pan, Zheng, Moyer, o"connor, Wang, Zheng, Wang, Schroeter, Zhou and Schweitzer, 2016. Molecular evidence of keratin and melanosomes in feathers of the Early Cretaceous bird Eoconfuciusornis. Proceedings of the National Academy of Sciences. 113(49), E7900-E7907.
Zheng, O'Connor, Wang, Pan, Wang, Wang and Zhou, 2017. Exceptional preservation of soft tissue in a new specimen of Eoconfuciusornis and its biological implications. National Science Review. 4(3), 441-452.
Naval�n, Meng, Marug�n-Lob�n, Zhang, Wang, Xing, Liu and Chiappe, 2018 (online 2017). Diversity and evolution of the Confuciusornithidae: Evidence from a new 131-million-year-old specimen from the Huajiying Formation in NE China. Journal of Asian Earth Sciences. 152, 12-22.
Pan, Li, Wang, Zhao, Wang and Zheng, 2022 (online 2021). Unambiguous evidence of brilliant iridescent feather color from hollow melanosomes in an Early Cretaceous bird. National Science Review. 9(2), nwab227.
Wang, Hu, Zhang, Wang, Zhao, Sullivan and Xu, 2022. A new confuciusornithid bird with a secondary epiphyseal ossification reveals phylogenetic changes in confuciusornithid flight mode. Communications Biology. 5:1398.
C. shifan Wang, Hu, Zhang, Wang, Zhao, Sullivan and Xu, 2022
Early Albian, Early Cretaceous
Xiaotaizi, Jiufotang Formation, Liaoning, China
Holotype- (PMOL AB 00178) (175 g, 4 year old adult) skull (46.3 mm), mandibles, ten cervical vertebrae, thirteen dorsal vertebrae, partial dorsal ribs, synsacrum, five caudal vertebrae, pygostyle (21.7 mm), scapulocoracoids (scapula 32.3, coracoid 17.3 mm), furcula, humeri (40.8 mm), radii (35.1 mm), ulnae (35.7 mm), scapholunares, pisiforms, metacarpals I (7.1 mm), epiphyseal ossifications, phalanges I-1 (15.9 mm), manual unguals I (14.1 mm), carpometacarpi (20.4 mm), phalanx II-1 (13.7 mm), phalanx II-2 (15.4 mm), manual ungual II (3.2 mm), phalanx III-2 (9.0 mm), phalanx III-3 (10.8 mm), manual unguals III (7.5 mm), manual claw sheath, ilia (23.0 mm), pubes (42.2 mm), ischia (16.4 mm), femora (33.9 mm), tibiotarsi (39.8 mm), fibula, metatarsals I, phalanges I-1 (4.3 mm), pedal unguals I (3.7 mm), tarsometatarsi (21.4 mm), phalanges II-1 (5.9 mm), phalanges II-2 (6.1 mm), pedal unguals II (7.3 mm), phalanges III-1 (6.3 mm), phalanges III-2 (4.3 mm), phalanges III-3 (5.4 mm), pedal unguals III (5.2 mm), phalanges IV-1 (3.6 mm), phalanges IV-2 (2.6 mm), phalanges IV-3 (2.5 mm), phalanges IV-4 (4.1 mm), pedal unguals IV (5.9 mm), pedal claw sheaths, body feathers
Diagnosis- (after Wang et al., 2022) myohyoid foramen in splenial; synsacrum ventrally keeled; angle of 75 degrees between scapula and coracoid (compared to 65 degrees in Yangavis, and 90 degrees in C. sanctus and Changchengornis); scapula widens distal to midshaft then tapers toward distal end; proximomedial edge of humerus strongly curved; deltopectoral crest with relatively low height/length ratio of 0.36 (compared to 0.39 in C. zhengi, 0.41 in C. dui, and >0.6 in C. sanctus, Changchengornis and Yangavis); extensor process medially projected nearly half the width of distal articular surface of metacarpal I; metacarpal III slightly bowed laterally; intermetacarpal space between metacarpals II and III wider than metacarpal III; distal third of pubis strongly curved posteriorly; proximal end of metatarsal III transversely compressed between metatarsals II and IV; metatarsal IV with a lateral flange two-thirds down shaft.
Other diagnoses- Of the characters listed by Wang et al. (2022)- "ventral process of surangular absent" is a plesiomorphy compared to C. sanctus; 'coracoid/scapula length ratio of 0.56 (compared to 0.51 in C. sanctus, 0.53 in Changchengornis, and 0.55 in Yangornis)' is a small difference that is also imprecise due to scapulocoracoid fusion.
Comments- Wang et al. (2022) used O'Connor's bird matrix to recover C. shifan sister to C. sanctus, with Changchengornis, Yangavis, C. dui and C. zhengi successively further from the pairing.  They noted "the results suggest that additional taxonomic work will be needed to refine the definition and diagnosis of Confuciusornis, and in particular to determine whether or not C. dui and perhaps even C. shifan should be moved out of the genus."
Reference- Wang, Hu, Zhang, Wang, Zhao, Sullivan and Xu, 2022. A new confuciusornithid bird with a secondary epiphyseal ossification reveals phylogenetic changes in confuciusornithid flight mode. Communications Biology. 5:1398.
C. sanctus Hou, Zhou, Gu and Zhang, 1995
= Confuciusornis suniae Hou, 1997
= Jinzhouornis zhangjiyingia Hou, Zhou, Zhang and Gu, 2002
= Jinzhouornis yixianensis Hou, Zhou, Zhang and Gu, 2002
Late Barremian-Early Aptian, Early Cretaceous
Jianshangou Beds of Yixian Formation, Liaoning, China
Holotype- (IVPP V10918) skull (50 mm), mandible, humerus (49.6 mm), radius (45.77 mm), ulna (42 mm), scapholunare, pisiform, metacarpal I (9 mm), phalanx I-1, manual ungual I, carpometacarpus (II 22.5 mm, III 19 mm), phalanx II-1 (21 mm), proximal phalanx II-2, phalanx III-1 (5 mm), phalanx III-2 (14 mm), proximal phalanx III-3, manual claw sheath
Paratypes- ?(IVPP V10895) partial ilium, proximal pubis, proximal ischium, femur (33 mm), incomplete tibiotarsus (41 mm), fibular fragment, tarsometatarsus (20 mm), partial phalanx II-1 (7 mm), phalanx II-2 (5.2 mm), pedal ungual II (6.5 mm), phalanx III-1 (6 mm), phalanx III-2 (5 mm), phalanx III-3 (5 mm), pedal ungual III (8 mm), phalanx IV-1 (4 mm), phalanx IV-2 (3 mm), phalanx IV-3 (3 mm), phalanx IV-4 (4.5 mm), pedal ungual IV (7 mm), metatarsal V (8 mm), pedal claw sheaths, body feathers
?(IVPP V10920) feathers
?(IVPP V10921) feathers
?(IVPP V10922) feathers
?(IVPP V10923) feathers
?(IVPP V10924) feathers
?(IVPP V10925) feathers
Referred- (B-05 1_a) (female) specimen including skull (47.77 mm), humerus (51.2 mm), radius (43.62 mm), ulna (45.23 mm), femur (41.82 mm), tibiotarsus (52.51 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(B-05 2_b) (female) specimen including skull (56.29 mm), humerus (48.86 mm), radius (41.31 mm), ulna (42.73 mm), femur (41.39 mm), tibiotarsus (48.6 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(B-07) specimen including skull (48.82 mm), humerus (41.9 mm), radius (35.17 mm), ulna (35.17 mm), femur (36.06 mm) and tibiotarsus (40.58 mm) (Marugan-Lobon and Chiappe, 2022)
(BMNHC-PH691) specimen including humerus (47.64 mm), radius (41.24 mm), ulna (41.82 mm), femur (40.26 mm) and tibiotarsus (47.45 mm) (Marugan-Lobon and Chiappe, 2022)
(BMNHC-PH760) specimen including skull (54.12 mm), humerus (51.44 mm), radius (43.16 mm), ulna (44.71 mm), femur (43.81 mm) and tibiotarsus (48.32 mm) (Marugan-Lobon and Chiappe, 2022)
(BMNHC-PH766) (male) specimen including skull (62.96 mm), pygostyle, humerus (64.32 mm), radius (60.46 mm), ulna (57.43 mm), pubes, femora (59.06 mm), tibiotarsi (66.86 mm), tarsometatarsi, pedes, body feathers, remiges and retrices (Marug�n-Lob�n, Chiappe, Ji, Zhou, Gao, Hu and Meng, 2011)
(BMNHC-PH775) (male) specimen including humerus (66.8 mm), radius (54.99 mm), ulna (57.43 mm), femur (56.44 mm), tibiotarsus (66.43 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
(BMNHC-PH810) specimen including humerus (53.95 mm), radius (46.2 mm), ulna (47.36 mm), femur (44.58 mm) and tibiotarsus (49.62 mm) (Marugan-Lobon and Chiappe, 2022)
(BMNHC-PH986) (female) specimen including skull (59.75 mm), mandibles, cervical vertebrae, humerus (63.22 mm), radius (51.74 mm), ulna (56.93 mm), femur (51.87 mm), tibiotarsus (58.23 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(BPV 003) specimen including skull (67.8 mm), humerus (63.99 mm), radius (52.69 mm), ulna (56.03 mm), femur (56.63 mm) and tibiotarsus (64.91 mm) (Marugan-Lobon and Chiappe, 2022)
(BPV 2066) skull, partial mandibles, two cervical vertebrae, two dorsal vertebrae, dorsal ribs, synsacrum, caudal vertebrae, pygostyle, scapulocoracoids, furcula, humeri (51.57 mm), radii (one incomplete; 42.53 mm), ulnae (one incomplete; 45.39 mm), metacarpals I, phalanges I-1 (one partial), manual ungual I, carpometacarpi, phalanges II-1, proximal phalanges II-2, phalanx III-1, distal phalanx III-2, phalanges III-3, manual unguals III, incomplete pubes, incomplete femora (43.65 mm), incomplete tibiotarsi (53.03 mm), fibulae, phalanges I-1, pedal unguals I, tarsometatarsi, phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV (Guan et al., 1997)
(BSP 1999 I 15) (male) specimen including skull (64.74 mm), pygostyle (34.21 mm), humerus (68.55 mm), radius (57.8 mm), ulna (58.04 mm), metacarpal I (10.65 mm), phalanx I-1 (24.09 mm), manual ungual I (15.53 mm), carpometacarpus (mcII 31.90, mcIII 28.19 mm), phalanx II-1 (22.95 mm), phalanx II-2 (25.09 mm), manual ungual II (4.61 mm), phalanx III-1 (5.77 mm), phalanx III-2 (14.44 mm), pahalnx III-3 (18.06 mm), manual ungual III (10.74 mm), femur (59.47 mm), tibiotarsus (70.24 mm), metatarsal I (6.65 mm), phalanx I-1 (6.65 mm), pedal ungual I (7.24 mm), tarsometatarsus (mtII 26.88, mtIII 31.82, mtIV 30.87 mm), phalanx II-1 (7.74 mm), phalanx II-2 (9.81 mm), pedal ungual II (8.57 mm), phalanx III-1 (8.40 mm), phalanx III-2 (6.99 mm), phalanx III-3 (7.44 mm), phalanx IV-1 (5.70 mm), phalanx IV-2 (4.69 mm), phalanx IV-3 (4.40 mm), pahalnx IV-4 (6.04 mm), pedal ungual IV (9.16 mm) and retrices (Chiappe et al., 2008)
(CAGS 1) (male) specimen including humerus (55.08 mm), radius (49.67 mm), u;na (48.25 mm), femur (43.66 mm), tibiotarsus (47.73 mm) and retrices (Chiappe et al., 2008)
(CAGS-IG-T1; inside Sinocalliopteryx gigas referred specimen) scapulocoracoids, furcula, humeri, radii, metacarpal II, manual phalanges, incomplete pelvis, femoral fragment, pedal phalanx, fragments
....dorsal vertebra, scapulocoracoids, sternum, carpal, tibiotarsal fragment, phalanx (Xing et al., 2012)
(CLS-BNU) specimen including skull (66.92 mm), humerus (65.07 mm), radius (55.12 mm), ulna (57.59 mm), femur (55.52 mm) and tibiotarsus (63.91 mm) (Marugan-Lobon and Chiappe, 2022)
(CPT 233) (female) specimen including skull (57.85 mm), humerus (54.06 mm), radius (45.69 mm), ulna (46.75 mm), femur (42.01 mm), tibiotarsus (49.12 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(D1196) (male) specimen including skull (51.43 mm), humerus (53.16 mm), radius (41.36 mm), ulna (46.5 mm), femur (45.02 mm), tibiotarsus (52.54 mm) and retrices (Chiappe et al., 2008)
(D1873) (male) specimen including skull (63.83 mm), humerus (67.28 mm), radius (59.01 mm), ulna (62.93 mm), femur (57.16 mm), tibiotarsus (65.6 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
(D1874) (male) specimen including skull (71.68 mm), humerus (67.68 mm), radius (56.2 mm), ulna (59.7 mm), femur (52.17 mm), tibiotarsus (70 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
(D1880) (female) specimen including skull (45.17 mm), humerus (44.77 mm), radius (33.95 mm), ulna (33.97 mm), femur (36.52 mm), tibiotarsus (42.3 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(D1899) (male) specimen including humerus (48.16 mm), radius (42.75 mm), ulna (42 mm), femur (41.92 mm), tibiotarsus (48.6 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
(D2149) specimen including skull (71.29 mm), humerus (67.88 mm), radius (58.19 mm), ulna (54.46 mm), femur (53.1 mm) and tibiotarsus (66.46 mm) (Marugan-Lobon and Chiappe, 2022)
(D2150) (female) specimen including humerus (65.24 mm), radius (57.29 mm), ulna (60.59 mm), femur (51.71 mm), tibiotarsus (63.98 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(D2151) (male) specimen including skull (67.54 mm), humerus (66.9 mm), radius (50.39 mm), ulna (53.83 mm), femur (50.94 mm), tibiotarsus (63.16 mm) and retrices (Chiappe et al., 2008)
(D2454) (male) specimen including skull (68.22 mm), humerus (78.09 mm), radius (65.02 mm), ulna (69.96 mm), femur (58.49 mm), tibiotarsus (68.87 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
(D2507) (female) specimen including skull (71.93 mm), humerus (66.51 mm), radius (56.53 mm), ulna (57.63 mm), femur (56.23 mm), tibiotarsus (67.45 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(D2508) (male) specimen including humerus (60.61 mm), radius (48.32 mm), ulna (48.75 mm), femur (45.51 mm), tibiotarsus (51.45 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
(D2859) (male) specimen including skull (48.08 mm), humerus (51.8 mm), radius (42.23 mm), ulna (44.83 mm), femur (43.93 mm), tibiotarsus (50.82 mm) and retrices (Chiappe et al., 2008)
(D2860) (male) specimen including skull (55.92 mm), humerus (53.75 mm), radius (44.82 mm), ulna (46.84 mm), femur (44.04 mm), tibiotarsus (54.76 mm) and retrices (Chiappe et al., 2008)
(D2865) specimen including skull (55.15 mm), humerus (52.13 mm), radius (44.15 mm), ulna (46.01 mm), femur (48.51 mm) and tibiotarsus (51.42 mm) (Marugan-Lobon and Chiappe, 2022)
(GMV 1) (male) specimen including humerus (49.8 mm), radius (43.1 mm), ulna (45.2 mm), femur (43.8 mm), tibiotarsus (50.4 mm) and retrices (Chiappe et al., 2008)
(GMV 1?; different measurements and sex than the 2008 table) (female) specimen including humerus (43.76 mm), radius (34.01 mm), ulna (35.74 mm), femur (33.94 mm), tibiotarsus (40.3 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(GMV 2) (male) specimen including humerus (51.25 mm), radius (42.6 mm), ulna (44.6 mm), femur (42.4 mm), tibiotarsus (52.95 mm) and retrices (Chiappe et al., 2008)
(GMV 5; = GMV 2147) (male) specimen including anterior cervical vertebrae, cervical ribs, at least eight dorsal vertebrae, dorsal ribs, uncinate processes, partial sternum, eight sternal ribs, humeri (41.35, 42.24 mm), radius (35.63 mm), ulna (37.7 mm), manual ungual, femur (35.88 mm), tibiotarsus (43.91 mm) and retrices (Chiappe et al., 1999)
(GMV 6) specimen including humerus (52.86 mm), radius (43.17 mm), ulna (44.76 mm), femur (44.74 mm) and tibiotarsus (52.65 mm) (Chiappe et al., 2008)
(GMV 7) specimen including skull (68.6 mm), humerus (67.48 mm), radius (55.15 mm), ulna (56.87 mm), femur (55.91 mm) and tibiotarsus (67.05 mm) (Chiappe et al., 2008)
(GMV 8) (female) specimen including humerus (53.25 mm), radius (43.9 mm), ulna (45.3 mm), femur (45.7 mm), tibiotarsus (52.1 mm) and feathers (Chiappe et al., 2008)
(GMV 9) (female) specimen including humerus (50.95 mm), radius (43.15 mm), ulna (44.46 mm), femur (44.5 mm), tibiotarsus (52.2 mm) and feathers (Chiappe et al., 2008)
(GMV 14) (female) specimen including humerus (50.2 mm), radius (44.2 mm), ulna (46.2 mm), femur (44 mm), tibiotarsus (52.2 mm) and feathers (Chiappe et al., 2008)
(GMV 15) (female) specimen including humerus (61.8 mm), radius (52.46 mm), ulna (54.5 mm), femur (52.46 mm), tibiotarsus (64.3 mm) and feathers (Chiappe et al., 2008)
(GMV 16) (male) specimen including humerus (48.55 mm), radius (38.7 mm), ulna (40 mm) and retrices (Chiappe et al., 2008)
(GMV 16?) specimen including humerus (47.08 mm), radius (37.17 mm), ulna (39 mm), femur (41 mm) and tibiotarsus (47.45 mm) (Chiappe et al., 2008)
(GMV 19) (male) specimen including humerus (62 mm), radius (48.5 mm), ulna (52 mm), femur (51.5 mm), tibiotarsus (59.3 mm) and retrices (Chiappe et al., 2008)
(GMV 20-1) (female) specimen including humerus (52.85 mm), radius (44.6 mm), ulna (46.9 mm), femur (43.95 mm), tibiotarsus (53.7 mm) and feathers (Chiappe et al., 2008)
(GMV 20-2) (female) specimen including humerus (69.5 mm), radius (52.1 mm), ulna (58.6 mm), femur (54.8 mm), tibiotarsus (66.35 mm) and feathers (Chiappe et al., 2008)
(GMV 21-1) (female) specimen including humerus (64.6 mm), radius (51.9 mm), ulna (52.4 mm), tibiotarsus (63.3 mm) and feathers (Chiappe et al., 2008)
(GMV 22; = GMV 2149) specimen including dorsal vertebrae, dorsal ribs, six uncinate processes, gastralia, humerus (53.52 mm), radius (43.15 mm), ulna (44.91 mm), manual ungual, femora (45.45, 44.48 mm) and tibiotarsus (53.28 mm) (Chiappe et al., 1999)
(GMV 23; = GMV 2132) skull (68.46 mm), scerlotic plates, mandible, six cervical vertebrae, twelve dorsal vertebrae, dorsal ribs, gastralia, three caudal vertebrae, pygostyle, proximal scapulae, coracoids, furcula, humeri (68.10, 69.15 mm), radii (56.55, 56.53 mm), ulnae (58.45 mm), scapholunares, pisiform, metacarpals I (11.66, 11.51 mm), phalanges I-1, manual unguals I, carpometacarpi (II 32.86, 33.15 mm, III 25.54, 25.91 mm), phalanges II-1, phalanges II-2, manual unguals II, phalanx III-1, phalanges III-2, phalanges III-3, manual unguals III, partial ilium, pubes, femora (55.63 mm), tibiotarsi (one incomplete; 66.05 mm), fibula, proximal tarsometatarsus (Chiappe et al., 1999)
(GMV 24; = GMV 2155) (female) specimen including humeri (~51.38, 52.16 mm), radius (43.59 mm), ulna (45.88 mm), femora (44.51, 45.79 mm), tibiotarsus (52.85 mm) and feathers (Chiappe et al. 1999)
(GMV 25) (female) specimen including humerus (61.3 mm), radius (50.7 mm), ulna (53.5 mm), femur (53 mm), tibiotarsus (58.1 mm) and feathers (Chiappe et al., 2008)
(GMV 26) (female) specimen including humerus (65.7 mm), radius (52.3 mm), ulna (54.8 mm), femur (56.1 mm), tibiotarsus (66.4 mm) and feathers (Chiappe et al., 2008)
(GMV 30) (female) specimen including humerus (40.85 mm), radius (34.5  mm), ulna (35.8 mm), femur (33.4 mm), tibiotarsus (40.9 mm) and feathers (Chiappe et al., 2008)
(GMV 32) (female) specimen including humerus (54.95 mm), radius (43.8 mm), ulna (46.2 mm), femur (46.9 mm), tibiotarsus (56.4 mm) and feathers (Chiappe et al., 2008)
(GMV 33) (female) specimen including humerus (58.5 mm), radius (50.2 mm), ulna (52.1 mm), femur (52.9 mm), tibiotarsus (63.1 mm) and feathers (Chiappe et al., 2008)
(GMV 36) (female) specimen including humerus (55 mm), radius (44.2 mm), ulna (47.35 mm), femur (48 mm), tibiotarsus (53.7 mm) and feathers (Chiappe et al., 2008)
(GMV 39) (female) specimen including humerus (63.7 mm), radius (52.8 mm), ulna (55.22 mm), femur (53.95 mm), tibiotarsus (64.8 mm) and feathers (Chiappe et al., 2008)
(GMV 40) (female) specimen including humerus (56.3 mm), radius (44.2 mm), ulna (47.2 mm), femur (45.45 mm), tibiotarsus (54.1 mm) and feathers (Chiappe et al., 2008)
(GMV 41) specimen including humerus (62.57 mm), radius (52.08 mm), ulna (54.38 mm), femur (53.16 mm) and tibiotarsus (61.6 mm) (Chiappe et al., 2008)
(GMV 42; = GMV 2133) (male) skull (55.59 mm), sclerotic ring, mandibles, six cervical vertebrae, two dorsal vertebrae, dorsal ribs, synsacrum, seven caudal vertebrae, pygostyle (32 mm), scapulae, coracoids, furcula, humeri (52.58, 53.53 mm), radii (43.65 mm), ulnae (45.38 mm), scapholunare, metacarpal I, phalanx I-1, proximal carpometacarpus, phalanx II-1, phalanx II-2, manual unguals II, phalanges III-2, phalanx III-3, ilia, pubes, ischia, femora (46.85 mm), tibiotarsi (53.29, 52.99 mm), fibulae (one partial), metatarsals I (6.48 mm), phalanges I-1, pedal unguals I, tarsometatarsi (25.64, 25.48 mm), phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, pedal claw sheaths, metatarsals V, body feathers, remiges, retrices (Chiappe et al., 1999)
(GMV 43) (female) specimen including humerus (67.2 mm), radius (54.6 mm), ulna (57.61 mm), femur (54.6 mm), tibiotarsus (66.5 mm) and feathers (Chiappe et al., 2008)
(GMV 44) (female) specimen including humerus (52.1 mm), radius (42.45 mm), ulna (44.8 mm), femur (44.9 mm), tibiotarsus (55 mm) and feathers (Chiappe et al., 2008)
(GMV 46) (male) specimen including humerus (66.9 mm), radius (52.55 mm), ulna 56.1 mm), femur (55.4 mm), tibiotarsus (67 mm) and retrices (Chiappe et al., 2008)
(GMV 50) (female) specimen including humerus (62.9 mm), radius (52.75 mm), ulna (56.2 mm), femur (54.45 mm), tibiotarsus (63.8 mm) and feathers (Chiappe et al., 2008)
(GMV 52) (female) specimen including humerus (52.7 mm), radius (43.7 mm), ulna (45.4 mm), femur (44.25 mm), tibiotarsus (53.7 mm) and feathers (Chiappe et al., 2008)
(GMV 53) (female) specimen including humerus (67.65 mm), radius (55.85 mm), ulna (60.6 mm), femur (55.6 mm), tibiotarsus (65.6 mm) and feathers (Chiappe et al., 2008)
(GMV 54) (female) specimen including humerus (67.7 mm), radius (53.6 mm), ulna (57.45 mm), femur (55.9 mm), tibiotarsus (65.75 mm) and feathers (Chiappe et al., 2008)
(GMV 55-1) (female) specimen including humerus (69.25 mm), radius (57.25 mm), ulna (59.15 mm), femur (57.5 mm), tibiotarsus (66.6 mm) and feathers (Chiappe et al., 2008)
(GMV 56-1) (female) specimen including humerus (50.1 mm), radius (41.3 mm), ulna (45.5 mm), femur (42.8 mm), tibiotarsus (51.95 mm) and feathers (Chiappe et al., 2008)
(GMV 56-2) (female) specimen including humerus (51.1 mm), radius (43.2 mm), ulna (45.25 mm), femur (44.5 mm), tibiotarsus (53.55 mm) and feathers (Chiappe et al., 2008)
(GMV 57; = GMV 2154) (male) specimen including sternal ribs, humeri (63.14, 64.19 mm), radius (52.05 mm), ulna (53.4 mm), femora (51.72, 53.08 mm), tibiotarsus (63 mm), tarsometatarsus, retrices (Chiappe et al., 1999)
(GMV 58-1; = GMV 2153-1) (male) specimen including skull, four cervical vertebrae, dorsal vertebrae, dorsal ribs, synsacrum, pygostyle, furcula, humeri (52.9 mm), radii (41.55 mm), ulnae (44.2 mm), scapholunares, metacarpals I, phalanges I-1, manual unguals I, carpometacarpi, phalanges II-1, phalanges II-2 (one proximal), phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III, partial ilia, pubes, femora (45.19, 45.3 mm), tibiotarsi (54.5 mm), tarsometatarsus, pedal phalanges, body feathers, retrices (Chiappe et al., 1999)
(GMV 58-2; = GMV 2153-2) (male) specimen including skull, mandible, cervical vertebrae, dorsal vertebrae, dorsal ribs, gastralia, synsacrum, seven caudal vertebrae, pygostyle, scapula, coracoid, partial furcula, partial sternum sternal ribs, humeri (44.28, 45.15 mm), radii (36.7 mm), ulna (39 mm), ilia, femora (37.72 mm), distal tibiotarsus, tarsometatarsus, phalanx II-1, phalanx II-2, pedal ungual II, phalanx III-1, phalanx III-2, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, three pedal unguals, body feathers, retrices (Chiappe et al., 1999)
(GMV 59-1) (female) specimen including humerus (65.75 mm), radius (53.1 mm), ulna (57 mm), femur (55.7 mm), tibiotarsus (67.25 mm) and feathers (Chiappe et al., 2008)
(GMV 59-2) (female) specimen including humerus (63.75 mm), radius (49.8 mm), ulna (54.45 mm), femur (55 mm), tibiotarsus (61.1 mm) and feathers (Chiappe et al., 2008)
(GMV 60) (female) specimen including humerus (52.9 mm), radius (43.7 mm), ulna (44.9 mm), femur (43.7 mm), tibiotarsus (50.77 mm) and feathers (Chiappe et al., 2008)
(GMV 61) (female) specimen including humerus (58.29 mm), radius (49.84 mm), ulna (51.98 mm), femur (47.6 mm), tibiotarsus (60.7 mm) and feathers (Chiappe et al., 2008)
(GMV 62) (female) specimen including humerus (61.6 mm), radius (50.17 mm), ulna (51.35 mm), femur (53.7 mm), tibiotarsus (64.1 mm) and feathers (Chiappe et al., 2008)
(GMV 66-1) (female) specimen including humerus (51.9 mm), radius (43.91 mm), ulna (45.1 mm), femur (43.9 mm), tibiotarsus (53.05 mm) and feathers (Chiappe et al., 2008)
(GMV 66-2) (female) specimen including humerus (65.45 mm), radius (51.8 mm), ulna (55.4 mm), femur (52.95 mm), tibiotarsus (63.7 mm) and feathers (Chiappe et al., 2008)
(GMV 67-1) (female) specimen including humerus (66.3 mm), radius (57.2 mm), ulna (55.5 mm), femur (54.05 mm), tibiotarsus (66.15 mm) and feathers (Chiappe et al., 2008)
(GMV 67-2) (male) specimen including humerus (52.4 mm), radius (42.9 mm), ulna (45.14 mm), femur (42.72 mm), tibiotarsus (49.5 mm) and retrices (Chiappe et al., 2008)
(GMV 69-1) (female) specimen including humerus (64 mm), radius (51.7 mm), ulna (55.4 mm), femur (51.9 mm), tibiotarsus (61.5 mm) and feathers (Chiappe et al., 2008)
(GMV 69-2) (female) specimen including humerus (64.5 mm), radius (51.8 mm), ulna (54.2 mm), femur (51.8 mm), tibiotarsus (61.5 mm) and feathers (Chiappe et al., 2008)
(GMV 73) (female) specimen including humerus (58.85 mm), radius (48.75 mm), ulna (50.7 mm), femur (48.4 mm), tibiotarsus (57.85 mm) and feathers (Chiappe et al., 2008)
(GMV 75; = GMV 2150) (male) specimen including skull, mandibles, cervical vertebrae, dorsal vertebrae, pygostyle, coracoids, humeri (~50.82, 51.54 mm), radii (39.9 mm), ulnae (44.05 mm), scapholunare, metacarpal I, phalanx I-1, carpometacarpi (one partial), phalanges II-1, phalanx II-2, ilium, femur (44.96 mm), incomplete tibiotarsus (51.2 mm), body feathers, remiges, retrices (270 mm) (Chiappe et al., 1999)
(GMV 76; = GMV 2151) (female) specimen including humerus (50.88 mm), radius (41.67 mm), ulna (44.83 mm), manus, femora (43.74, 44.09 mm), tibiotarsus (51.09 mm) and remiges (Chiappe et al., 1999)
(GMV 77) (female) specimen including humerus (56.15 mm), radius (45.65 mm), ulna (47.88 mm), femur (47.9 mm), tibiotarsus (54.85 mm) and feathers (Chiappe et al., 2008)
(GMV 78) specimen including skull (55.59 mm), humerus (52.34 mm), radius (43.52 mm), ulna (44.63 mm), femur (43.09 mm) and tibiotarsus (51.82 mm) (Chiappe et al., 2008)
(GMV 101) specimen including skull (53.52 mm), humerus (42.5 mm), radius (36.63 mm), ulna (36.92 mm), femur (34.38 mm) and tibiotarsus (39.21 mm) (Chiappe et al., 2008)
(GMV 2130; 2030 in Chiappe et al., 2008) (female) skull, sclerotic ossicles, mandible, cervical vertebrae, at least eight dorsal vertebrae, dorsal ribs, uncinate processes, synsacrum, caudal vertebrae, pygostyle, proximal scapula, incomplete sternum, nine sternal ribs, humeri (47.86, 47.69 mm), radii (38.87 mm), ulnae (40.73 mm), scapholunare, pisiform, metacarpals I (5.99 mm), phalanges I-1, manual unguals I, carpometacarpi (II 21.11 mm), phalanges II-1, phalanges II-2 (one proximal), phalanges III-2, phalanges III-3, manual claw sheaths, partial ilia, femora (one proximal; 41.78 mm), tibiotarsus (48.70 mm), metatarsals I (5.48, 5.5 mm), phalanx I-1, pedal ungual I, tarsometatarsi (23.21, 23.28 mm), phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, pedal claw sheaths, body feathers, remiges (to 210 mm) (Chiappe et al., 1999)
(GMV 2131; 2031 in Chiappe et al., 2008) (male) skull (47 mm), partial mandible, partial hyoids, seven cervical vertebrae, twelve dorsal vertebrae, dorsal ribs, synsacrum, five caudal vertebrae, pygostyle, furcula, partial sternum, five sternal ribs, humeri (~40.01, 41.86 mm), radii (35.21, 34.89 mm), ulnae (35.05 mm), metacarpals I (~6.45 mm), phalanges I-1, manual unguals I, carpometacarpi (II 20.78, III 18.38 mm), phalanges II-1, phalanx II-2, manual ungual II, phalanges III-2, phalanx III-3, manual ungual III, manual claw sheaths, partial ilia, femoral fragments (36.14 mm), partial tibiotarsi (41.67 mm), metatarsals I (4.43 mm), phalanges I-1, pedal unguals I, tarsometatarsi (20.52, 20.65 mm), phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, pedal claw sheaths, body feathers, remiges, retrices (Chiappe et al., 1999)
(GMV 2141) distal tibiotarsus, metatarsal I, phalanx I-1, pedal ungual I, tarsometatarsus, phalanx II-1, phalanx II-2, pedal ungual II, phalanx III-1, phalanx III-2, phalanx III-3, pedal ungual III, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV (Chiappe et al., 1999)
(GMV 2142) incomplete skeleton (Chiappe et al., 1999)
(GMV 2146) (male) specimen including skull (55.06 mm), mandibles, cervical vertebrae, uncinate processes, seven caudal vertebrae, humeri (41.95, 42.69 mm), radius (34.68 mm), ulna (35.62 mm), manus, femur (34.62 mm), tibiotarsus (41.63 mm), remiges, retrices (Chiappe et al., 1999)
(GMV 2148) specimen including skull, mandible, cervical vertebrae, dorsal vertebrae, dorsal ribs, scapulocoracoid, furcula, humeri, radii, ulnae, metacarpal I, phalanx I-1, manual ungual I, carpometacarpi, phalanx II-1, phalanx II-2, manual ungual II, phalanx III-1, phalanges III-2, phalanges III-3, manual ungual III, pubes (one partial), femora, proximal tibiotarsi, body feathers (Chiappe et al., 1999)
(GMV 2152) specimen including gastralia, sternal fragment and femur (Chiappe et al., 1999)
(GVM 常州-1GVM 常州-1) (female) specimen including humerus (49.8 mm), radius (43.1 mm), ulna (45.2 mm), femur (43.8 mm), tibiotarsus (50.4 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(GVM 常州-2GVM 常州-2) (female) specimen including humerus (51.25 mm), radius (42.6 mm), ulna (44.6 mm), femur (42.4 mm), tibiotarsus (52.95 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(IVPP V10918) (female) specimen including skull (57.43 mm), humerus (49.6 mm), radius (45.77 mm), ulna (46.33 mm), femur (43.1 mm), tibiotarsus (51.52 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(IVPP V10920) (female) specimen including humerus (42 mm), radius (35.45 mm), ulna (36.17 mm), femur (34.6 mm), tibiotarsus (40.69 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(IVPP V10928) specimen including sternum (Zhang et al., 2008)
(IVPP V11304) specimen including humerus (60 mm), radius (52.76 mm), ulna (53.58 mm), femur (50.67 mm) and tibiotarsus (59.28 mm) (Marugan-Lobon and Chiappe, 2022)
(IVPP V11305) specimen including scapulocoracoid (Wu, Bailleul, Li, O'Connor and Zhou, 2021)
(IVPP V11308; holotype of Confuciusornis suniae) skull, sclerotic ring, mandibles, hyoids, nine cervicals (6 is 8 mm), partial cervical rib, ten dorsal vertebrae (8 is 5 mm), dorsal ribs, four uncinate processes(?), gastralia, sacrum (50 mm), ten caudal vertebrae, pygostyle, scapulae (42.5 mm), proximal coracoid, partial furcula, sternum (43 mm), sternal ribs, humerus (53.18 mm), radius (45.96 mm), ulna (46.46 mm), scapholunares, pisiforms, distal carpal III, metacarpals I (8 mm), phalanges I-1 (one proximal; 19 mm), manual ungual I, carpometacarpi (one incomplete; II 25.5 mm, III 18 mm), phalanges II-1 (18.5 mm), phalanges II-2 (20 mm), manual ungual II (8 mm), phalanx III-1 (5 mm), phalanx III-2 (14 mm), phalanx III-3 (15 mm), manual ungual III (16 mm), manual claw sheaths, ilium (33.5 mm), pubis (47 mm), ischium, femora (46.79 mm), patella?, tibiotarsi (55.83 mm), fibulae (~41 mm), metatarsal I, phalanx I-1, pedal ungual I, metatarsal II, phalanx 2-1, phalanx II-2, pedal ungual II, metatarsal III (26 mm), phalanx III-1, phalanx III-3, pedal ungual III (10 mm), metatarsal IV, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV (12 mm), pedal claw sheaths, metatarsal V, feathers (Hou, 1997)
(IVPP V11370) (840 or 801g, male) specimen including skull (76.25 mm), sacrum (35 mm), humerus (68.14 mm), radius (54.89 mm), ulna (58.21 mm), femur (58.89 mm), tibiotarsus (69.12 mm), phalanx II-1, phalanx II-2, phalanx IV-3, phalanx IV-4 and retrices (Xu et al., 2000)
(IVPP V11372) (370 or 352 g, female) specimen including skull (54.42 mm), humerus (52.77 mm), radius (44.62 mm), ulna (47.07 mm), femur (44.73 mm), tibiotarsus (51.09 mm) and feathers (Chiappe et al., 2008)
(IVPP V11374) (520 or 494 g, female) specimen including skull (54.2 mm), humerus (51.46 mm), radius (44.4 mm), ulna (45.84 mm), femur (45.86 mm), tibiotarsus (53.33 mm) and feathers (Hutchinson, 2001)
(IVPP V11375) (430 or 407 g, male) specimen including skull (55.63 mm), humerus (53.28 mm), radius (42.87 mm), ulna (44.68 mm), femur (45.74 mm), tibiotarsus (52.76 mm) and retrices (Chiappe et al., 2008)
(IVPP V11548) (male) specimen including skull (44.6 mm), scapulocoracoid, humerus (42.1 mm), radius (36.8 mm), ulna (34.7 mm), femur (36.59 mm), tibiotarsus (41.35 mm) and retrices (Wu, Bailleul, Li, O'Connor and Zhou, 2021)
(IVPP V11552) specimen including skull (54.19 mm), mandible, cervical vertebrae, dorsal vertebrae, dorsal ribs, uncinate processes, synsacrum (29.9 mm), pygostyle (~28.2 mm), scapulocoracoids (scapulae ~49.2 mm; coracoids ~20.6 mm), furcula (21.6 mm), sternum (~42.2 mm), sternal ribs, humeri (55.62 mm), radii (45.62 mm), ulnae (46.72 mm), pisiforms, metacarpals I (9.7 mm), phalanges I-1, manual unguals I (22.1 mm), carpometacarpi (II 27.5 mm, III ~25.5 mm), phalanges II-1 (20.3 mm), phalanx II-2 (21.2 mm), manual ungual II (7.8 mm), phalanges III-1 (~4.2 mm), phalanges III-2 (8.6 mm), phalanges III-3 (~18.6 mm), manual unguals III (~15 mm), manual claw sheaths, ilium (31.6 mm), pubis (45.7 mm), ischium (~25.5 mm), femur (45.61 mm), tibiotarsus (52.71 mm), fibula (30.2 mm), phalanx I-1 (5.7 mm), tarsometatarsus (29.5 mm), phalanx II-1 (6.9 mm), phalanx II-2 (8 mm), phalanx III-1 (7.9 mm), phalanx III-2 (6.5 mm), phalanx IV-1 (5 mm), phalanx IV-2 (4.2 mm), phalanx IV-3 (4.1 mm), phalanx IV-4 (4.8 mm) (Zhou, 1999)
(IVPP V11619) specimen including humerus (52 mm), ulna (47 mm), carpometacarpus (27 mm), pubis (47 mm), femur (47 mm), tibiotarsus (54 mm), tarsometatarsus (25 mm) (Zhou and Zhang, 2002)
(IVPP V11640) (760 or 723 g, male) specimen including skull (66.26 mm), mandible, cervical vertebrae, dorsal vertebrae, dorsal ribs, sacrum, scapulae, humeri (64.94 mm), radii (50.81 mm), ulnae (54.86 mm), metacarpal I, phalanx I-1, manual ungual I, carpometacarpus (30 mm), phalanx II-1, phalanx II-2, manual claw sheath, ilia, femora (55 mm), tibiotarsi (65.42 mm), metatarsal I, phalanx I-1, pedal ungual I, tarsometatarsi (30 mm), phalanges II-1, phalanges II-2, pedal unguals II, phalanx III-1, phalanx III-2, phalanx III-3, pedal ungual III, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, peal phalanges, pedal unguals, body feathers, remiges, retrices (Hou et al., 2002)
(IVPP V11794) specimen including humerus (63.5 mm), ulna (55 mm), carpometacarpus (32 mm), femur (55 mm) and tibiotarsus (66 mm) (Hou et al., 2002)
(IVPP V11795) specimen including scapulocoracoid (Wu, Bailleul, Li, O'Connor and Zhou, 2021)
(IVPP V11795) specimen including humerus (44 mm), ulna (37 mm), femur (36 mm) and tibiotarsus (42 mm), (Hou et al., 2002)
(IVPP V12352; holotype of Jinzhouornis zhangjiyingia) (male) skull (62.28 mm), mandible, three cervical vertebrae, seven dorsal vertebrae, dorsal ribs, pygostyle, scapula, sternum, sternal ribs, humeri (52.32 mm), radii (43.43 mm), ulnae (45.83 mm), scapholunare, pisiform, metacarpals I, phalanges I-1, manual unguals I, carpometacarpi, phalanges II-1, phalanges II-2, manual unguals II, phalanx III-1, phalanx III-2, phalanges III-3, manual unguals III, manual claw sheaths, femora (43.09 mm), tibiotarsi (49.29 mm), metatarsals I, phalanges I-1, pedal unguals I, tarsometatarsi, phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, retrices (Hou et al., 2002)
(IVPP V13156) (female) specimen including skull (67.63 mm), cervical vertebrae, dorsal vertebrae, dorsal ribs, sacrum, caudal vertebrae, pygostyle (31.23 mm), scapula, humerus (60.97 mm), radius (50.91 mm), ulna (53.52 mm), scapholunare, pisiform, metacarpal I, phalanx I-1, manual ungual I, carpometacarpus, phalanx II-1, phalanx II-2, manual ungual II, phalanx III-1, phalanx III-2, phalanx III-3, manual ungual III, manual claw sheaths, ilia, pubis, femora (53.16 mm), tibiotarsi (60.81 mm), fibula, metatarsal I, phalanx I-1, pedal unguals I, tarsometatarsi (31.66 mm), phalanges II-1, phalanges II-2, pedal unguals II, phalanx III-1, phalanx III-2, phalanx III-3, pedal unguals III, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, pedal claw sheaths, body feathers, remiges (Zhou and Zhang, 2006)
(IVPP V13167) (male) specimen including humerus (66.9 mm), radius (54.89 mm), ulna (56.57 mm), femur (54.6 mm), tibiotarsus (62.1 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
(IVPP V13168) (male) specimen including skull (53 mm), pygostyle (27.41 mm), humerus (53 mm), radius (44.21 mm), ulna (42.6 mm), femur (43.5 mm), tibiotarsus (52 mm), tarsometatarsus (27.13 mm) and retrices (Wang, O'Connor, Pan and Zhou, 2017)
(IVPP V13171) (female) skull (66.55 mm), mandibles, hyoids, six cervical vertebrae, at least nine dorsal vertebrae, dorsal ribs, synsacrum, two proximal caudal vertebrae, pygostyle (31.98 mm), scapulocoracoids, humeri (61.94 mm), radii (52.31 mm), ulna (54.43 mm), pisiform, metacarpal I, phalanx I-1, manual ungual I, carpometacarpus, phalanx II-1, phalanx II-2, manual ungual II, phalanx III-1, phalanx III-2, phalanx III-3, manual ungual III, manual claw sheaths,  ilia, partial ischium, femur (55.96 mm), tibiotarsi (62.68 mm), fibula, tarsometatarsi (31.13 mm), pedal phalanges, body feathers, remiges (Zhang et al., 2010)
(IVPP V13172.1) (subadult) specimen including skull (46.53 mm), pygostyle (27.56 mm), scapulocoracoid, humerus (49.74 mm), radius (41.72 mm), ulna (43.1 mm), scapholunare, semilunate carpal, metacarpal I, phalanx I-1, manual ungual I, metacarpal II, phalanx II-1, phalanx II-2, manual ungual II, metacarpal III, phalanx III-1, phalanx III-2, phalanx III-3, manual ungual III, manual claw sheaths, ilium, femur (44.98 mm), tibiotarsus (53.86 mm), tarsometatarsus (26.69 mm), propatagium, remiges (Feduccia and Czerkas, 2015)
(IVPP V13175a) (male) specimen including skull (72.6 mm), humerus (64.86 mm), radius (54.16 mm), ulna (55.9 mm), femur (53.13 mm), tibiotarsus (64.86 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
(IVPP V13175b) (male) specimen including humerus (61.12 mm), radius (50.35 mm), ulna (52.65 mm), femur (52.39 mm), tibiotarsus (60.65 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
?...(IVPP V13175x; it's unknown whether these measurements are from V13175a or V13175b) specimen including pygostyle (30.08 mm) and tarsometatarsus (31.51 mm) (Wang, O'Connor, Pan and Zhou, 2017)
(IVPP V13178) (male) specimen including pygostyle (32.21 mm), humerus (66.9 mm), radius (55.8 mm), ulna (55.7 mm), femur (56.3 mm), tibiotarsus (64.5 mm), tarsometatarsus (31.67 mm) and retrices (Wang, O'Connor, Pan and Zhou, 2017)
(IVPP V13338) specimen including scapulocoracoid (Wu, Bailleul, Li, O'Connor and Zhou, 2021)
(IVPP V14224) (female) specimen including humerus (45.5 mm), radius (38.1 mm), ulna (39.39 mm), femur (38.68 mm), tibiotarsus (46.19 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(IVPP V14373) (female) specimen including skull (43.4 mm), humerus (44.35 mm), radius (36 mm), ulna (37 mm), femur (33 mm), tibiotarsus (41.5 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(IVPP V14385) specimen including skull (52.15 mm), dorsal ribs, scapulocoracoid, furcula, sternum, humerus (55 mm), radius (45.49 mm), ulna (47.24 mm), femur (47 mm) and tibiotarsus (54.15 mm) (Wu, Bailleul, Li, O'Connor and Zhou, 2021)
(IVPP V14412; holotype of Jinzhouornis yixianensis) skull, partial mandible, cervical vertebrae, dorsal vertebrae, dorsal ribs, partial pygostyle, scapulae (one incomplete), incomplete humeri, incomplete radii, ulnae (one incomplete, one partial), scapholunare, metacarpal I, phalanx I-1, manual ungual I, carpometacarpi (one proximal), phalanx III-1, incomplete phalanx III-3, partial manual ungual III, manual claw sheath, partial femora (~40 mm), tibiotarsi (one distal; ~50 mm), metatarsals I, phalanges I-1, pedal unguals I, tarsometatarsi (~24 mm), phalanx II-1, phalanges II-2, pedal unguals II, phalanx III-1, phalanges III-2, phalanx III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV (Hou et al., 2002)
(IVPP V100921) (female) specimen including humerus (55.76 mm), radius (48.72 mm), ulna (49.58 mm), femur (45.58 mm), tibiotarsus (53.46 mm) and feathers (Chiappe et al., 2008)
(IVPP V110304) skull (73 mm), sclerotic ring, mandible (62 mm), hyoids, atlas, axis, cervical vertebrae 3-9, cervical ribs, anterior dorsal vertebra, dorsal ribs, gastralia, caudal vertebra, scapula (52 mm), coracoid (28 mm), furcula (27 mm across), sternum (45 mm), humeri (one proximal; 61 mm), radius (52 mm), ulna (55 mm), scapholunare, pisiform, metacarpal I (11 mm), phalanx I-1 (19 mm), manual ungual I (16.5 mm), carpometacarpus (II 32.5 mm, III 31 mm), phalanx II-1, phalanx II-2, manual ungual II (8 mm), phalanx III-2, phalanx III-3, manual ungual III (21 mm), proximal femur, tibiotarsi (66 mm), fibula (35 mm) proximal tarsometatarsus, remiges (Hou et al., 1996)
(IVPP castW) specimen including skull (70.85 mm), humerus (61 mm), radius (51.1 mm), ulna (52.51 mm), femur (56.1 mm) and tibiotarsus (63 mm) (Marugan-Lobon and Chiappe, 2022)
(IVPP coll.) specimen including skull, mandible, cervical vertebrae, dorsal vertebrae, dorsal ribs, pygostyle, radius, ulna, manus, pubis, femur, tibiotarsus, pedal digit I, tarsometatarsus, pedal digit II, pedal digit III, pedal digit IV, feathers (Hou et al., 1996)
(IVPP coll.) specimen including skull, mandible, cervical vertebrae, dorsal vertebrae, caudal vertebrae, furcula, humerus, radius, ulna, manus, femora, tibiotarsi, trsometatarsi, pedal phalanges, pedal unguals (Hou et al., 1996)
(IVPP coll.) specimen including gastralia, pygostyle, furcula, sternum, humerus, radius, ulna, manus, pubes, femora, tibiotarsi, tarsometatarsi, pedal digits, remiges (Hou et al., 1996)
?(IVPP coll.) remiges (Hou et al., 1996)
(IVPP coll.) four specimens with skulls (Hou et al., 1996)
?(IVPP coll.) many feathers (Hou, 1997)
(JM-UKr-1996/15) skeleton including skull (60.74 mm), humerus (64.59 mm), radius (53.55 mm), ulna (55.81 mm), femur (55.4 mm) and tibiotarsus (62.4 mm) (Viohl, 1997)
(JM-UKr-1997/1) skeleton including skull (46.99 mm), mandible, six cervical vertebrae, dorsal vertebrae, dorsal ribs, synsacrum, humerus (51.79 mm), radius (43.9 mm), ulna (46.6 mm), scapholunare, pisiform, metacarpal I, phalanx I-1, manual ungual I, carpometacarpus, phalanx II-1, phalanx II-2, manual ungual II, phalanx III-1, phalanx III-2, phalanx III-3, manual ungual III, femur (46.1 mm), tibiotarsus (53.29 mm) and feathers (Viohl, 1997)
(JM-UKr-2005/1) (male) specimen including humerus (59.31 mm), radius (44.4 mm), ulna (46.68 mm), femur (44.08 mm), tibiotarsus (54 mm) and retrices (Chiappe et al., 2008)
(LACM 153346) specimen including skull (67.44 mm), humerus (59.51 mm), radius (50.75 mm), ulna (51.65 mm), femur (55.43 mm) and tibiotarsus (63.56 mm) (Chiappe et al., 2008)
(LL. 12418) (male) specimen including skull (51 mm), humerus (50.06 mm), radius (41.1 mm), ulna (42.93 mm), femur (44.93 mm) and tibiotarsus (49.76 mm) and retrices (Chiappe et al., 2008)
(LPM 0009) specimen (O'Connor, 2009)
(LPM 0012) (male) specimen including humerus (50 mm), radius (42.94 mm), ulna (41.2 mm), femur (45.03 mm), tibiotarsus (53.24 mm) and retrices (Chiappe et al., 2008)
(LPM 0205) (male) specimen including skull (71 mm), humerus (61.87 mm), radius (53.69 mm), ulna (56.01 mm), femur (53.8 mm), tibiotarsus (62.39 mm) and retrices (Marugan-Lobon and Chiappe, 2022)
(LPM 0228A) (female) specimen including humerus (69.23 mm), radius (57.73 mm), ulna (54.39 mm), femur (50.87 mm) and tibiotarsus (63.98 mm) (Chiappe et al., 2008)
(LPM 0228B) (female) specimen including skull (64.02 mm), humerus (60.89 mm), radius (54.23 mm), ulna (49.18 mm), femur (51.71 mm) and tibiotarsus (63.04 mm) (Chiappe et al., 2008)
(LPM 0228C) (female) specimen including skull (58.78 mm), humerus (61.15 mm), radius (50.96 mm), ulna (55.6 mm), femur (55.19 mm) and tibiotarsus (63.96 mm) (Chiappe et al., 2008)
(LPM 0229A) (male) specimen including humerus (57.23 or 62.48 mm), radius (46.86 or 51.05 mm), ulna (49.42 or 51.01 mm), femur (47.12 or 52.02 mm), tibiotarsus (58.2 or 63.86 mm) and retrices (Chiappe et al., 2008)
(LPM 0229B) (male) specimen including humerus (47.43 or 51.01 mm), radius (38.03 or 41.99 mm), ulna (37.95 or 41.21 mm), femur (43.34 or 43.8 mm), tibiotarsus (51.69 or 51.54 mm) and retrices (Chiappe et al., 2008)
(LPM 0233) (male) specimen including skull (47.06 mm), humerus (41.01 mm), radius (41.04 mm), ulna (43.19 mm), femur (32.44 mm), tibiotarsus (36.85 mm) and retrices (Chiappe et al., 2008)
(MB Av.1168-1171; Berlin) (female) specimen including skull (54.51 mm), pygostyle (23.50 mm), scapula (40.73 mm), furcula, humerus (45.51 mm), radius (39.87 mm), ulna (41.72 mm), phalanx I-1 (14.93 mm), manual ungual I (10.3 mm), phalanx II-1 (17.34 mm), phalanx II-2 (18.94 mm), manual ungual II (4.28 mm), phalanx III-2 (11.81 mm), phalanx III-3 (13.06 mm), manual ungual III (7.27 mm), femur (41.71 mm), tibiotarsus (48.88 mm), metatarsal I (4.11 mm), phalanx I-1 (5.04 mm), pedal ungual I (5.19 mm), tarsometatarsus (mtII 21.14, mtIII 23.46, mtIV 21.80 mm), phalanx II-1 (6.06 mm), phalanx II-2 (6.55 mm), pedal ungual II (6.63 mm), phalanx III-1 (6.63 mm), phalanx III-2 (5.42 mm), phalanx III-3 (6.33 mm), pedal ungual III (6.72 mm), phalanx IV-1 (4.44 mm), phalanx IV-2 (3.77 mm), phalanx IV-3 (3.14 mm), phalanx IV-4 (4.4  mm), pedal ungual IV (5.85 mm) and feathers (Chiappe et al., 2008)
(MCFO-0374) (550 or 522 g, male) specimen including humerus (47.54 mm), radius (38 mm), ulna (41 mm), femur (41.4 mm), tibiotarsus (46.85 mm) and retrices (Chiappe et al., 2008)
(MCFO-0589A) (male) specimen including skull (70.41 mm), humerus (61.66 mm), radius (52.37 mm), ulna (56.27 mm), femur (53.21 mm), tibiotarsus (64.34 mm) and retrices (Chiappe et al., 2008)
(MCFO-0589B) (male) specimen including humerus (69.11 mm), radius (56.02 mm), ulna (59.14 mm), femur (56.28 mm), tibiotarsus (66.64 mm) and retrices (Chiappe et al., 2008)
(NBM 258) (female) specimen including skull (47.92 mm), humerus (51.75 mm), radius (41.15 mm), ulna (44.05 mm), femur (43.44 mm), tibiotarsus (52.09 mm) and feathers (Chiappe et al., 2008)
(NGIP-139379a) (male) skull (62.46 mm), mandibles, cervical vertebrae, dorsal vertebrae, dorsal ribs, sacrum, pygostyle, humeri (65.65 mm), radii (54.09 mm), ulnae (55.69 mm), manus, ilium, pubes, femora (52.12 mm), tibiotarsi (61.51 mm), pedes, body feathers, remiges and retrices (Marugan-Lobon and Chiappe, 2022)
(NGIP-139379b) (female) skull (56.2 mm), mandible, cervical vertebrae, dorsal ribs, synsacrum, pygostyle, humeri (54.08 mm), radius (46.63 mm), ulna (47.71 mm), manus, ilium, pubes, femora (48.32 mm), tibiotarsi (56.16 mm), pedes, body feathers and remiges (Marugan-Lobon and Chiappe, 2022)
(NGMC 98-8-2; MOR 1063) (adult) dorsal vertebrae, few dorsal ribs, gastralia, synsacrum, caudal vertebrae, pygostyle, coracoid, humeri, radii, ulnae, scapholunares, metacarpals I, phalanges I-1, manual unguals I, carpometacarpi, phalanges II-1 (one proximal), phalanx II-2, manual ungual II, phalanx III-2, incomplete phalanges III-3, manual unguals III, pubes, ischium, femora, tibiotarsi, metatarsal I, phalanx I-1, pedal ungual I, tarsometatarsi, phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, metatarsal V (de Ricqles et al., 2003)
(NHMW1997z/0000) (female) specimen including skull (67.11 mm), humerus (66.4 mm), radius (56.81 mm), ulna (57.37 mm), femur (55.23 mm), tibiotarsus (66.67 mm) and feathers (Chiappe et al., 2008)
(NHMW1997z/0112) specimen including cervical vertebrae, dorsal ribs, scapulocoracoid, humerus, radius, ulna, metacarpal I, phalanx I-1, manual ungual I, carpometacarpus, phalanx II-1, phalanx II-2, manual ungual II, phalanx III-2, phalanx III-3, manual ungual III, body feathers and remiges (Peters and Ji, 1999)
(PMO.161.632) (female) specimen including humerus (50.88 mm), radius (39.9 mm), ulna (45.22 mm), femur (42.65 mm), tibiotarsus (51.87 mm) and feathers (Chiappe et al., 2008)
(PMOL 00031) specimen including skull (54.07 mm), dorsal vertebrae, dorsal ribs, sacrum, caudal vertebrae, pygostyle, humerus (52.16 mm), radius (46.55 mm), ulna (49.84 mm), ilium, pubes, ischium, femora (43.73 mm), tibiotarsi (51.01 mm), phalanx I-1, pedal ungual I, tarsometatarsi and pedal digits (Marug�n-Lob�n, Chiappe, Ji, Zhou, Gao, Hu and Meng, 2011)
(PMOL AB 00048) specimen including skull (50.05 mm), humerus (55.86 mm), radius (41.7 mm), ulna (46.85 mm), femur (45.08 mm) and tibiotarsus (53.49 mm) (Marugan-Lobon and Chiappe, 2022)
(PMOL AB 00049) specimen including skull (54.63 mm), humerus (57.85 mm), radius (48.83 mm), ulna (50.23 mm), femur (49.21 mm) and tibiotarsus (57.83 mm) (Marugan-Lobon and Chiappe, 2022)
(PMOL AB 00124) specimen including skull (74.79 mm), humerus (71.86 mm), radius (60.56 mm), ulna (62.34 mm), femur (60.16 mm) and tibiotarsus (69.36 mm) (Marugan-Lobon and Chiappe, 2022)
?(PMOL AB 00150) specimen including metacarpal I, phalanx I-1 and carpometatacarpus (Wang, Hu, Zhang, Wang, Zhao, Sullivan and Xu, 2022)
(PMOL AB 00152) specimen including humerus (63.69 mm), radius (51.69 mm), ulna (54.46 mm), femur (57.12 mm) and tibiotarsus (63.33 mm) (Marugan-Lobon and Chiappe, 2022)
(PMOL AB 00153) (female) specimen including skull (68.31 mm), humerus (69.93 mm), radius (52.77 mm), ulna (53.27 mm), femur (51.52 mm), tibiotarsus (63.68 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(PMOL AB 00162) specimen including humerus (67.96 mm), radius (52.13 mm), ulna (53.23 mm), femur (54.53 mm) and tibiotarsus (65.49 mm) (Marugan-Lobon and Chiappe, 2022)
(PMOL B 00005) specimen including skull (52.92 mm), humerus (51.93 mm), radius (41.75 mm), ulna (43.91 mm), femur (40.88 mm) and tibiotarsus (49.9 mm) (Marugan-Lobon and Chiappe, 2022)
(PMOL B 00034) specimen including humerus (53.6 mm), radius (42.5 mm), ulna (43.69 mm), femur (43.46 mm) and tibiotarsus (51.84 mm) (Marugan-Lobon and Chiappe, 2022)
(PMOL B 00125) (female) specimen including humerus (53.23 mm), radius (45.09 mm), ulna (46.32 mm), femur (45.32 mm), tibiotarsus (53.18 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(PMOL B 00151) (female) specimen including skull (67.95 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(SMFAv-412) skeleton including atlas, axis, postaxial cervical vertebrae, humerus (49.71 mm), radius (41.23 mm), ulna (42.81 mm), scapholunare, pisiform, metacarpal I, phalanx I-1, carpometacarpus, femur (43.73 mm) and tibiotarsus (50.4 mm) (Peters, 1996)
(SMFAv-416) (male) skeleton including skull (60.77 mm), mandible, humerus (65.29 mm), radius (54.58 mm), ulna (56.1 mm), ilium, femur (54.53 mm), tibiotarsus (63.64 mm) and retrices (Peters, 1996)
(SMFAv-417) specimen including humerus (50.73 mm), radius (40.49 mm), ulna (43.85 mm), femur (46.73 mm) and tibiotarsus (53,68 mm) (Chiappe et al., 2008)
(SMFAv-419) (female) specimen including skull (47.15 mm), humerus (41.3 mm), radius (37.91 mm), ulna (38.51 mm), femur (36.05 mm) and tibiotarsus (42.33 mm) (Chiappe et al., 2008)
(SMFAv-420) specimen including humerus (66.6 mm), radius (54.04 mm), ulna (56.15 mm), femur (55.97 mm) and tibiotarsus (66.81 mm) (Chiappe et al., 2008)
(SMFAv-421) skeleton including tarsometatarsus (Peters, 1996)
(SMFAv-423) skeleton including cervical vertebrae, dorsal vertebrae, dorsal ribs, sacapulocoracoids, furcula, sternum, sternal ribs, femur, tarsometatarsus (Peters, 1996)
(SMNK-Pal.6413) specimen including skull (52.33 mm), humerus (48.31 mm), radius (40.32 mm), ulna (42.16 mm), femur (43.71 mm) and tibiotarsus (51.57 mm) (Chiappe et al., 2008)
(STM 13-6) specimen including skull (68.3 mm), humerus (61.6 mm), radius (53.9 mm), ulna (53.9 mm), femur (50.9 mm), tibiotarsus (62.9 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-7) specimen including skull (67.6 mm), humerus (64.1 mm), radius (55.9 mm), ulna (56.6 mm), femur (52.5 mm), tibiotarsus (64 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-28) specimen including humerus (42.13 mm), radius (35 mm), ulna (34.6 mm), femur (36.1 mm), tibiotarsus (38.3 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-30) specimen including sternum (O'Connor et al., 2015)
(STM 13-32) skull (51 mm), mandibles, cervical vertebrae, dorsal vertebrae, dorsal ribs, synsacrum, caudal vertebrae, pygpstyle, scapulae, coracoids, furcula, humeri (52.78 mm), radii (42.02 mm), ulnae (41.04 mm), scapholunares, metacarpals I, phalanges I-1, manual unguals I, carpometacarpi, phalanges II-1, phalanges II-2, manual digits III, ilia, pubes, femora (43.07 mm), tibiotarsi (51.4 mm), fibula, tarsometatarsi, pedal phalanges, pedal unguals, body feathers, remiges (Zheng et al., 2013)
(STM 13-40) (subadult) specimen including humerus (O'Connor et al., 2015)
(STM 13-44) skull, mandible, cervical vertebrae, dorsal vertebrae, dorsal ribs, uncinate processes, sacrum, caudal vertebrae, pygostyle, scapulocoracoids, furcula, sternum, humeri, radius, ulnae, scapholunare, metacarpal I, phalanx I-1, manual ungual I, carpometacarpi, phalanges II-1, phalanges II-2, manual ungual II, phalanges III-1, phalanges III-2, phalanx III-3, ilium, femora, tibiotarsi, phalanges I-1, pedal ungual I, tarsometatarsi, phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, body feathers, remiges (Zheng et al., 2013)
(STM 13-52) specimen including gastralia, sternum, sternal ribs, pubis and femur (Zheng et al., 2014)
(STM 13-55) skull, mandible, cervical vertebrae, dorsal ribs, sacrum, caudal vertebrae, pygostyle, scapulae, humeri, radii, ulnae, scapholunare, metacarpals I, phalanges I-1, manual unguals I, carpometacarpi, phalanges II-1, phalanges II-2, manual ungual II, phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III, ilia, ischia, femora, tibiotarsi, fibula, metatarsals I, phalanges I-1, pedal unguals I, tarsometatarsi, phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, pedal claw sheaths, body feathers, remiges (Zheng et al., 2013)
(STM 13-57) skull, mandible, cervical vertebrae, dorsal ribs, gastralia, pygostyle, scapula, furcula, sternum, humeri, radius, ulna, metacarpal I, phalanx I-1, manual unguals I, carpometacarpus, phalanx II-1, phalanx II-2, manual ungual II, phalanx III-1, phalanx III-2, phalanx III-3, manual ungual III, manual claw sheaths, femur, tibiotarsus, metatarsal I, phalanx I-1, pedal unguals I, tarsometatarsi, phalanges II-1, phalanges II-2, pedal ungual II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal ungual IV, pedal claw sheaths, body feathers, remiges (Zheng et al., 2013)
(STM 13-92) specimen including humerus (44.85 mm), radius (40.9 mm), ulna (39.3 mm), femur (36.3 mm), tibiotarsus (42.8 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-109) specimen including skull (45.7 mm), humerus (42.7 mm), radius (35.4 mm), ulna (34.9 mm), femur (35.9 mm), tibiotarsus (39 mm mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-165) specimen including skull (45.7 mm), humerus (43.2 mm), radius (35.7 mm), ulna (35.35 mm), femur (35.2 mm), tibiotarsus (40.15 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-169A) specimen including skull (54 mm), humerus (52 mm), radius (41.8 mm), ulna (45.1 mm), femur (37 mm), tibiotarsus (52.2 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-169B) specimen including humerus (62.3 mm), radius (52.2 mm), ulna (56.1 mm), femur (53.4 mm), tibiotarsus (63.3 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-169C) specimen including skull (51.26 mm), humerus (50.4 mm), radius (42.74 mm), ulna (44.9 mm), femur (43 mm), tibiotarsus (54.15 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-191) specimen including skull (45.3 mm), humerus (47.8 mm), radius (40.69 mm), ulna (41.14 mm), femur (39.7 mm) and tibiotarsus (46.2 mm) (Marugan-Lobon and Chiappe, 2022)
(STM 13-203) specimen including skull (41.8 mm), sternum, humerus (41 mm), radius (37.7 mm), ulna (37.4 mm), femur (33.3 mm), tibiotarsus (40.45 mm) and feathers (Zheng, Wang, O'Connor and Zhou, 2012)
(STM 13-204) specimen including skull (49.1 mm), humerus (40.7 mm), radius (40.5 mm), ulna (38.4 mm), femur (36.6 mm), tibiotarsus (41.2 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-228) specimen including skull (43 mm), humerus (44.65 mm), radius (36.6 mm), ulna (38.5 mm), femur (37.45 mm), tibiotarsus (41.3 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-229) specimen including humerus (40.2 mm), radius (35.5 mm), ulna (38.5 mm), femur (33.7 mm), tibiotarsus (40.95 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-231) specimen including sternum (O'Connor et al., 2015)
(STM 13-242) specimen including sternum (Zheng, Wang, O'Connor and Zhou, 2012)
(STM 13-276) specimen including humerus (48.5 mm), radius (41.2 mm), ulna (41.2 mm), femur (41.5 mm), tibiotarsus (47.1 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-277) specimen including humerus (45.74 mm), radius (37.9 mm), ulna (40.6 mm), femur (36.8 mm), tibiotarsus (42.7 mm) and feathers (Marugan-Lobon and Chiappe, 2022)
(STM 13-331) skull, mandibles, hyoid, cervical vertebrae, dorsal vertebrae, dorsal ribs, uncinate processes, gastralia, sacrum, caudal vertebrae, pygostyle, scapulocoracoids, sternum, sternal ribs, humeri, radii, ulnae, scapholunares, pisiform, metacarpals I, phalanges I-1, manual unguals I, carpometacarpi, phalanges II-1, phalanges II-2, manual unguals II, phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III, manual claw sheaths, ilia, pubis, ischium, femora, tibiotarsi, metatarsals I, phalanges I-1, pedal unguals I, tarsometatarsi, phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, pedal claw sheaths, body feathers (Zheng et al., 2013)
(STM 14-183) (subadult) specimen including dorsal ribs, sternum and sternal ribs (O'Connor et al., 2015)
(STM coll.) 105 specimens including scapulocoracoid (Wu, Bailleul, Li, O'Connor and Zhou, 2021)
(TMP 1998.014.0001) (male) specimen including skull (61.34 mm), humerus (62.77 mm), radius (51.99 mm), ulna (53.93 mm), femur (52.43 mm), tibiotarsus (63.33 mm) and retrices (Chiappe et al., 2008)
(TMP 1998.014.0002) (male) specimen including skull (54.23 mm), humerus (51.33 mm), radius (44.32 mm), ulna (45.39 mm), femur (46.7 mm), tibiotarsus (52.67 mm) and retrices (Chiappe et al., 2008)
(private coll.; Bonn specimen) (male) skull (54.03 mm), mandible, hyoids, eight cervical vertebrae, five dorsal vertebrae, dorsal ribs, gastralia, synsacrum, seven caudal vertebrae, two chrevrons, pygostyle, scapulocoracoids, furcula, sternum, humeri (51.71 mm), radii (44.58 mm), ulnae (45.55 mm), scapholunares, pisiforms, metacarpals I, phalanges I-1, manual unguals I, carpometacarpi, phalanges II-1, phalanges II-2, manual ungual II, phalanx III-1, phalanges III-2, phalanges III-3, manual unguals III, manual claw sheaths, ilia, pubes, ischium, femora (43.42 mm), tibiotarsi (50.15 mm), fibula, metatarsals I, phalanges I-1, pedal unguals I, tarsometatarsi, phalanx II-1, phalanx II-2, pedal unguals II, phalanx III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, pedal claw sheaths, metatarsal V, body feathers, remiges (Goernemann, 1999)
(male) specimen including skull, mandible, cervical vertebrae, dorsal ribs, sacrum, pygostyle, scapulae, coracoids, humeri, radii, ulnae, metacarpal I, carpometacarpus, phalanx II-1, phalanx II-2, phalanx III-2, phalanx III-3, manual ungual III, ilia, femora, tibiotarsi, tarsometatarsi, pedal phalanges, pedal unguals, body feathers, remiges, retrices (Martin et al., 1998)
several hundred specimens (Martin et al., 1998)
specimen including skull, mandible, five cervical vertebrae, dorsal vertebrae, dorsal ribs, gastralia, synsacrum, caudal vertebrae, pygostyle, scapulae, humeri, radii, ulnae, metacarpal I, phalanx I-2, manual ungual I, carpometacarpi, phalanx II-1, phalanx III-2, phalanx III-3, manual ungual III, manual claw sheath, ilia, distal pubes, femora, tibiotarsi, fbulae, metatarsals I, phalanges I-1, pedal unguals I, tarsometatarsi, phalanx II-1, phalanx II-2, pedal ungual II, phalanx III-1, phalanx III-2, phalanx III-3, pedal ungual III, phalanx IV-1, phalanx IV-2, phalanx IV-3, phalanx IV-4, pedal ungual IV, pedal phalanges, pedal unguals, body feathers, remiges (Paul, 2002)
specimen including skull, mandible, seven cervical vertebrae, dorsal vertebrae, dorsal ribs, uncinate processes, gastralia, synsacrum, caudal vertebrae, pygostyle, scapulocoracoids, humeri, radii, ulnae, scapholunare, metacarpals I, phalanges I-1, manual ungual I, carpometacarpi, phalanges II-1, phalanges II-2, manual unguals II, phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III, ilia, distal pubes, femora, tibiotarsi, metatarsal I, phalanges I-1, pedal unguals I, tarsometatarsi, phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, body feathers, remiges (Paul, 2002)
(male) specimen including skull, mandible, sclerotic ring, cervical vertebrae, dorsal vertebrae, dorsal ribs, synsacrum, caudal vertebrae, pygostyle, scapulocoracoids, furcula, humeri, radii, ulnae, scapholunares, pisiform, metacarpals I, phalanges I-1, manual unguals I, carpometacarpi, phalanges II-1, phalanges II-2, manual unguals II, phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III, manual claw sheaths, ilium, pubes, femora, tibiotarsi, metatarsal I, phalanx I-1, tarsometatarsi, phalanges II-1, phalanges II-2, pedal unguals II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanges IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, pedal claw sheaths, body feathers, remiges, retrices (Paul, 2002)
skull, mandibles, hyoids (Paul, 2002)
nine specimens (Li and Zhang, 2011)
Early Albian, Early Cretaceous
Jiufotang Formation, Liaoning, China
?(IVPP V13313) skull, mandible, ten cervical vertebrae, cervical ribs, over eight dorsal vertebrae, dorsal ribs, synsacrum, four caudal vertebrae, chevrons, scapulocoracoids, furcula, sternum, humeri (58 mm), radii, ulnae (49 mm), metacarpal I, phalanges I-1, manual ungual I, carpometacarpi, phalanges II-1, phalanges II-2, manual unguals II, phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III, manual claw sheath, ilium, pubes, ischia (one proximal), femora (47 mm), tibiotarsi (54 mm), tarsometatarsi, phalanges II-1, phalanges II-2, pedal ungual II, phalanges III-1, phalanges III-2, phalanges III-3, pedal unguals III, phalanges IV-1, phalanx IV-2, phalanges IV-3, phalanges IV-4, pedal unguals IV, body feathers, remiges, seven to nine Jinanichthys vertebrae and ribs (Dalsatt et al., 2006)
Diagnosis- (after Chiappe et al., 1999) tarsometatarsus excavated on plantar surface (unknown in C. feducciai).
(after Hou et al., 1999) anterior dentary expanded ventrally (also in C. feducciai).
(proposed) peg-and-socket quadratojugal-quadrate articulation (unknown in other confuciusornithids); double-headed quadrate (unknown in other confuciusornithids); ventral surangular process invading external mandibular fenestra (unknown in C. feducciai); enlarged surangular foramen (also in C. zhengi; unknown in C. feducciai); coracoid foramen absent (unknown in C. feducciai); five pairs of sternal ribs (unknown in C. zhengi); proximoposterior surface of deltopectoral crest concave (unknown in other confuciusornithids); m. humerotricipitalis groove on posterodistal humerus well developed (unknown in C. feducciai); pubic boot absent (unknown in C. dui and C. feducciai).
Comments- Confuciusornis was described based on three poorly preserved specimens and several feathers found in 1993. Strangely, two nearly identical English versions of the description were published, the first in the August issue of Chinese Science Bulletin (Hou et al., 1995b) and the second in the September issue (Hou et al., 1995c).  The only differences are superscript reference numbers and slightt alteration of Viohl's bibliographic entry in the September version, and the August version spelling the species name sanstus in the title and systematic section (but not the introduction or figure captions).  Following ICZN Article 32.2.1, "If a name is spelled in more than one way in the work in which it was established, then, except as provided otherwise in this Article, the correct original spelling is that chosen by the First Reviser", which in this case is Hou et al. in the September issue.  An even earlier version would also seem to exist, as referenced by Hou et al. (1995d), who listed "Hou, L., Zhou, Z., Gu, Y. & Zhang, H. Chinese Sci. Bull. 10, 61-63 (1995).", which should be the Chinese version of the journal based on the papers describing Cathayornis.  The holotype was described well by Hou et al. (1995b,c), though the skull in figure 5b labeled IVPP V109185 may be a typo for the counterpart. While Hou et al. claim the carpometacarpus is unfused, there are no obvious sutures between the semilunate carpal and metacarpals II and III in the excellent photograph in Zhou and Hou (2002). Hou et al. (1995d) erred in stating the postorbital was absent (Zhou, 1999), and incorrectly reconstructed Confuciusornis with a long tail and third manual digit longer than the second. Hou (1997) described the holotype in great detail, probably more than was objectively possible considering the state of the specimen. He also misinterpreted the snout region, mistaking the naris for the antorbital fenestra, the nasal processes of the premaxillae for the nasals, the posterior premaxilla for the maxilla, and part of the maxilla for the prefrontal. One of the paratypes is IVPP V10895, which was similarly described by both Hou et al. (1995b,c) then in more detail by Hou (1997). Similar to the situation for the holotype, Hou is overzealous in his description, since the large photo in Zhou and Zhang (2006) indicates the entire dorsal ilium and distal pubis are unpreserved, while the hindlimb is fragmented and often only preserved as impressions. The ischium was misinterpreted as complete, although it lacks its distal half, while the pubis was described as unfused to its counterpart, which has been shown to be untrue by specimens which actually preserve the distal pubis. Hou describes a patella which is more likely to be a proximal fibular fragment, and a single distal tarsal which is probably the anteriorly projecting astragalar condyles of the tibiotarsus, but that entire area is fragmented. While measurements for the hallux are provided and metatarsal I illustrated, the entire digit is missing in the specimen. While the tibiotarsofemoral proportions are different from C. dui, they fall into the range of C. feducciai as well as C. sanctus. As both species occur in the same formation, IVPP V10895 cannot be definitively referred to C. sanctus. The paratype distal tibiotarsus and pes IVPP V10919 was made the holotype of Confuciusornis chuonzhous by Hou (1997), but is probably indeterminate within Confuciusornis as discussed under its entry. Finally, six feathers were made paratypes, but these cannot be distinguished from those of other maniraptorans in the formation.
In 1995, four more specimens were discovered by Hou and were initially photographed in Hou et al. (1996). These were fairly complete, but only IVPP V110304 has been subsequently described (Hou, 1997). These specimens included the first pygostyle and pectoral girdle known for Confuciusornis. Oddly, Hou et al. (1996) reported that some specimens lack a pygostyle, but this has not been seen in any described specimen. Hou's description of IVPP V110304 retains his misidentification of snout elements from the holotype, and oddly identifies a septomaxilla (an element unknown in dinosaurs) at the anterior margin of the external naris. This is more likely a vomer or palatine fragment. The sternum was described with anterior and posterior ends reversed.
Peters (1996) and Peters and Ji (1998, 1999) described four specimens from the SMFAv. Guan et al. (1997) described a specimen (BPV 2066), which I believe to be the specimen featured on Digimorph's page (Maisano, 2001). Viohl (1997) described two additional specimens (JM-UKr-1996/15 and 1997/1). Chiappe et al. (1999) published a detailed monograph on Confuciusornis, largely basing it on specimens from the GMV (2130-2133, 2141, 21142, 2146-2155). They noted several areas where the species is polymorphic- ventral tapering of the postorbital; dentary symphysis fusion; two dorsals fused to synsacrum; hypocleidium developed as a swelling; faint keel on sternum; elongate paired retrices. Whether these differences are ontogenetic, sexual, indivual or even taxonomic variation is not known, though generally the specimens with elongate retrices are thought of as males (and labeled as such above). Goernemann (1999) described a privately owned specimen in detail. Hou's (1999) thesis includes a section on Confuciusornis, which was published as Zhou and Farlow (2001) and Zhou and Hou (2002), with figures and data also being used for Martin et al. (1998). Zhou's study was largely based on the specimen IVPP V11552, while Martin et al. mentioned hundreds of specimens were known. Of note is that most of the known IVPP specimens have not been examined to ensure they are C. sanctus instead of C. feducciai or another confuciusornithid, and that many specimens have uncertain provenance, so may be from other members of the Yixian Formation or even the Jiufotang Formation.
Dalsatt et al. (2006) describe the first Confuciusornis specimen from the Jiufotang Formation. It is unlike C. dui in being large and having an anteriorly expanded dentary, large posterior surangular foramen, broad proximal metacarpal I, manual ungual I larger than III, and a comparatively short tibiotarsus. Yet it is more similar to C. dui in lacking a surangular process invading the external mandibular fenestra. The short forelimb, deltopectoral foramen, robust manual digit I, and lack of anterolateral or anteriorly curving posterolateral sternal processes are unlike C. feducciai. Finally, the deep lateral dorsal central fossae, deltopectoral foramen and elongated coracoid are unlike C. zhengi. It it tentatively placed in C. sanctus here, but the presence of a character which is more similar to C. dui and the higher stratigraphic placement suggests it may be a new species.
Confuciusornis suniae- Hou (1997) described Confuciusornis suniae (mistyped Confuciusornis shuzhi in the English summary) based on the nearly complete skeleton IVPP V11308. He distinguished it from C. sanctus based on several characters. The notched anterior median premaxillary margin is present in C. sanctus as well (e.g. GMV-2133). The long dorsal premaxillary process, large external nares and short frontal are present in C. sanctus and were only thought to be absent by Hou due to his misinterpretation of the snout in that species. Hou also states the bulbous frontal with thickened orbital rim is distinct in the text, but the former is present in C. sanctus (e.g. GMV 2133), while the latter may be due to misidentified palpebrals. "Well developed" parietals are too vague to comment on. The cervical vertebrae were said to differ from those of C. sanctus in several characters in the diagnosis (flat and broad centra and neural arches; pleurocoels present; narrow and low neural spines), with others mentioned in the discussion (lateral projection of the transverse processes; thin and expanded centra; prezygapophyses positioned laterally and anteriorly projected). Besides the vague "thin and expanded" centra, the characters are all seen in C. sanctus (Chiappe et al., 1999). Chiappe et al. note cervical pleurocoels are often hard to distinguish, and Hou notes the C. sanctus specimens he studied had poorly preserved cervicals which may have broad centra too. The dorsal vertebrae being "long and thin" is too vague to be useful. "Long and deep grooves" are said to be present in the dorsal central fossae, but their interior morphology is undescribed in C. sanctus. Hou describes three fused "lumbar" vertebrae, but these are clearly the first three sacrals, adding to the four vertebrae described as sacrals to give the standard count of seven for Confuciusornis. Fused sacral neural spines are present in C. sanctus as well (e.g. GMV 2153), whereas the fusion of sacrals to the ilia is not known to be absent in C. sanctus and is ontogenetically variable in any case. "Caudal vertebrae basically fused" is seen in all avebrevicaudans. Chiappe et al. (1999) note the sternal morphology (long and narrow with deep elongate lateral recesses; heart-shaped; without lateral processes) cannot be verified in the specimen, as most of it is covered by other bones. The lateral process may be broken off, while the shape difference is largely due to Hou describing C. sanctus' sternum backwards. Hou et al. notes many supposed appendicular differences in his description, most of which are also present in C. sanctus (ventral tubercle of humerus less prominent; concavity of ectepicondyle of humerus; prominent fibular trochlea on femur; prominent fibular crest on tibia; metatarsus only fused proximally), or within the range of variation of C. sanctus (deltopectoral foramen size; metacarpal III robusticity; limb bone robusticity). A dorsal supracondylar process is reported, but the photo doesn't suggest its presence. The scapulotricipital sulcus on the distal humerus is not known to be absent in C. sanctus. Hou describes the ischium as follows, "The ischium is extremely autapomorphic as there are three processes extending off the main body: The first is relatively short, broad, and forms the posterior wall of the acetabulum. The second process is plate-shaped, extends, and expands obliquely dorsally from the distomedial side of the ilium to the vertebral column, appearing as though it encircles the most posterior portion of the synsacral vertebrae. The third and largest process is one which extends posteriorly to the distal end." The first process is clearly the ilial peduncle, the second is the proximodorsal process, and the third is the ischial shaft itself. These are found in C. sanctus too, but Hou was misled by the incomplete IVPP V10895 he used as the basis for that species' pelvic morphology. Finally, Hou states a prominent fourth trochanter is present, but the swelling is clearly absent in the right femur, and that of the left femur is more likely taphonomic. Hou again identifies a septomaxilla, no doubt erroneously. Ten free caudals are preserved, and the vertebrae making up the pygostyle are distinct, though the neural spines are fused distally. This is distinct from C. sanctus, which has seven free caudals and no differentiation within the pygostyle. Perhaps the specimen is young and the two distalmost free caudals would fuse into the pygostyle when it matured. Hou describes four "short thick rib segments" on the right of the specimen, which may be uncinate processes. He also states that though an olecranal fossa is absent, a small depressed region is observed, whereas Chiappe et al. noted no sign of an olecranal fossa. Although Chiappe et al. state a longitudinal groove is absent on the radius of C. sanctus, Hou reports such a groove in C. suniae that is present proximally. Hou reports five phalanges on manual digit III, the first two very short. This is near certainly caused by a break near the base of phalanx III-2. The ilial process noted over the acetabulum and compared to an antitrochanter is probably the supratrochanteric process. He notes a "low dorsal ridge" on the distal pubis, similar to that described by Paul (2002). A patella is described, though this has not been reported by Chiappe et al., and I am unaware of its presence in any non-ornithurine bird. Hou claims the notched premaxillary tip, subequal length of pedal digits III and IV and enlarged fourth pedal ungual indicate semiaquatic or aquatic habits. I see no reason these characters suggest this, and the first two are present in C. sanctus as well. As reported, the fourth pedal ungual is 20% longer than the third, which is unlike at least some C. sanctus specimens. However, pedal proportions among confuciusornithids are extremely variable, with digit length differing as much as 30% in feet of the same specimen.
The proximal humeral foramen and bowed manual phalanx II-2 confirm this is a Confuciusornis specimen, while the elongate sternal ribs, proximally robust first metacarpal and reduced manual ungual III suggest it is not C. dui. The distally expanded scapula, short forelimb, triangular deltopectoral crest with foramen and robust manual digit I suggests it is not C. feducciai. The dorsal central fossae distinguish it from C. zhengi. The ten free caudals, slightly developed olecranal fossa, radial groove and patella all differ from C. sanctus, but given Hou's record of erroneous interpretation, I'm cautious to accept these as real. I thus agree with the synonymization of Confuciusornis suniae with C. sanctus, as suggested by Chiappe et al. (1999).
Jinzhouornis- Jinzhouornis was named by Hou et al. (2002) in a monograph that has yet to be translated from Chinese. J. yixianensis is the type of the genus, while zhangjiyingia was referred to it. They have largely been ignored in the literature, though Zhou and Zhang (2006) and Zhang et al. (2008) both mention them as valid.
At least some of the characters supposedly diagnosing J. yixianensis are seen in Confuciusornis (eg. snout over 50% of cranial length; tubercle in middle of metatarsal II; small tubercle on metatarsal III) and most others are vague proportions that could also be applied to C. sanctus specimens (eg. long low skull; robust long snout; moderately sized orbit; extremely curved manual unguals; slender humerus). Chiappe et al. (2008) note the low skull is due to crushing and that the manual unguals are not more curved than C. sanctus. Though Hou et al. state the humerus was subequal in length to the scapula, it is clearly broken and was much longer than the scapula if complete. Characters like "braincase small" and "second manual digit not particularly expanded" appear to differ at first glance, but I have a feeling examination of the specimen would show otherwise. I cannot see digit II, but I do see digit III, which is of course more slender. Better photos would be needed to show the cervical vertebrae are shorter than Confuciusornis (Chiappe et al. find they are too incomplete to judge) and Confuciusornis may have had over twelve dorsal vertebrae. The taxon shows the proximal humeral foramen and reduced fourth metatarsal trochlea of Confuciusornis. It differs from C. dui in being large, lacking a proximally tapered metacarpal I and having a larger tibiotarsofemoral ratio for its size. It differs from C. feducciai in having a deltopectoral foramen and from C. zhengi in having deep lateral fossae on a dorsal centrum and a prominent scapular acromion. In 2002, I used some of the above data to provisionally propose J. yixianensis was synonymous with Confuciusornis, but could not then place it more exactly (Mortimer, DML 2002). Chiappe et al. (2008) have now examined the specimen in more detail and synonymized it with C. sanctus, which I agree with.
The diagnosis of Jinzhouornis zhangjiyingia contains characters that could be applied to Confuciusornis sanctus (eg. long large skull; premaxilla extends to posterior part of orbit; infratemporal fenestra well developed; orbit moderate in size; furcular ends widely separated) or are subject to individual variation (humeral shaft robust; furcula slender). Additionally, the premaxillae are said to underlie the frontal, but Chiappe et al. (2008) note the frontal is anteriorly displaced. Finally, the supposed quadratojugal-orbit cannot be confirmed (Chiappe et al., 2008). It shows the robust furcula, bowed manual phalanx II-2 and humeral foramen of Confuciusornis. The first manual ungual is much larger than the third and the anterior dentary is expanded, both unlike C. dui. The short forelimb, deltopectoral foramen and triangular deltopectoral crest are unlike C. feducciai. There also appear to be five pairs of sternal ribs, unlike C. dui and C. feducciai. In 2002, I used much of the above data to provisionally synonymize J. zhangjiyingia with C. sanctus (Mortimer DML, 2002), pending restudy. Chiappe et al. (2008) have recently done that restudy, finding J. zhangjiyingia plots with C. sanctus in limb proportions, and agree it is a junior synonym. Zhou et al. (2003) illustrated the skull and pes as examples of C. sanctus.
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C. sp. indet. (Chiappe et al., 1999)
Early Aptian, Early Cretaceous
Dawangzhangzi Beds of Yixian Formation, Liaoning, China
Material- two specimens (Chiappe, Ji, Ji and Norell, 1999)
Comments- Chiappe et al. note that two specimens they refer to Confuciusornis sanctus have been found in the Dawangzhangzi Beds, though which they are is uncertain (they may be unknowingly listed above in the main C. sanctus section). Zhou et al. (2003) lists C. sp. as being from that horizon. Zhongornis may be a juvenile representative of Dawangzhangzi Confuciusornis.
References- Chiappe, Ji, Ji and Norell, 1999. Anatomy and systematics of the Confuciusornithidae (Theropoda: Aves) from the Late Mesozoic of Northeastern China. Bulletin of American Museum of Natural History. 242, 1-89.
Zhou, Barrett and Hilton, 2003. An exceptionally preserved Lower Cretaceous ecosystem. Nature. 421, 807-814.
C. sp. indet. (Zhou et al., 2003)
Mid Aptian, Early Cretaceous
Jingangshan Beds of Yixian Formation, Liaoning, China
Comments- Zhou et al. (2003) list Confuciusornis sp. as being found in this member of the Yixian Formation, but none have yet been described. They may be C. sanctus, which seems to be found in both lower and higher sediments.
Reference- Zhou, Barrett and Hilton, 2003. An exceptionally preserved Lower Cretaceous ecosystem. Nature. 421, 807-814.