Zhongornis haoae (Gao et al. 2008; O'Connor and Sulivan 2014; D2455; Early Cretaceous) was considered the sister to all pygostylians not realizing that the pygostyle developed several times by convergence. Lack of fusion and bone texture indicate the Zhongornis holotype is a juvenile. The femoral heads and necks are not visible, perhaps not yet ossified. Even so, the wing feathers are well-develped, so the specimen is not a hatchling, but close to fledging, according to Gao et al.

Zhongjianornis yangi (Zhou and Li 2010; Early Cretaceous, IVPP V15900, pigeon-sized, scale bar on skull image is 1cm) nests with Confuciusornis in the LRT, but has a longer beak, shorter hands and smaller sternum. Pedal digit 4 is as long as 3. The present tracing is more precise than the original. Originally described as toothless, tiny teeth may still be present on the premaxilla and maxilla. Confuciusornithids have only 8 cervicals, one less than most birds.

Cratonavis zhui (Li et al 2023, Early Cretaceous) was considered a Chongmingia relative, but here nests with Zhongjianornis. The teeth are blunt. The orbit is long. The coracoid is triangular. Yet another pygostyle is present.

Confuciusornis sanctus (Hou et al. 1995, Early Cretaceous, GMV-2132) has no teeth, a short tail and large claws. The premaxilla is much larger than the maxilla, as in living birds like Struthio and Gallus. The neck is quite short. The humerus is perforated. Here it nests with one of the Late Jurassic birds, Wellnhoferia (see below) with which it shares a short tail without a pygostyle and has a hole in the humerus.

The MBAv1168 specimen (below, Elzanowski, Peters and Mayr 2018) is twice as tall, has a longer neck, shorter tail, smaller, wider pelvis and larger unguals and a longer pedal digit 4 among other traits. It has tiny teeth. In the LRT it nests with Changchengornis.

Changchengornis hengdaoziensis (Ji et al. 1999, Chiappe et al. 1999; GMV-2129) is an Early Cretaceous relative of Zhongornis and Confuciusornis preserved as a plate and counter plate, flattened, but complete and articulated... with feathers and skin outlines

Chiappe LM, Ji S-A, J Q, Norell MA 1999. Anatomy and systematics of the Confuciusornithidae (Theropoda:Aves) from the Late Mesozoic of northeastern China. Bulletin of the American Museum of Natural History 242: 89pp. PDF

Elzanowski A, Peters DS and Mayr G 2018. Cranial morphology of the Early Cretaceous bird Confuciusornis. Journal of Vertebrate Paleontology DOI:
10.1080/02724634.2018.1439832

Gao C-L, Chiappe LM, Meng Q-J, O’Connor JK, Wang X, Cheng X-D and Liu J-Y 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.

Hou L, Zhou Z, Gu Y and Zhang H 1995. Confuciusornis sanctus, a new Late Jurassic sauriurine bird from China. Chinese Science Bulletin 40: 1545–1551.

Li Z, Wang M, Stidham TA and Zhou Z 2023. Decoupling the skull and skeleton in a Cretaceous bird with unique appendicular morphologies. Nature Ecology & Evolution 96:

Ji Q, Chiappe L and Ji S 1999. A new Late Mesozoic confuciusornithid bird from China. Journal of Vertebrate Paleontology 19(1): 1–7.

O'Connor J-M and Sulivan C 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)1–9.

Zhou Z and Li FZZ 2010. A new Lower Cretaceous bird from Chna and tooth reduction in early avian evolution. Proceedings of the Royal Society B 277:219–227.

wiki/Changchengornis
wiki/Confuciusornis
wiki/Zhongornis
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