[D] Sinornis santensis [~/~]
Sereno & Rao, 1992
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Avialae Ornithothoraces Enantiornithes
Jiufotang Formation, Liaoning, China
Partial skull, many nearly complete postcranial skeletons.
Sinornis santensis shares several reptilian traits with Archaeopteryx.
The snout is hort and toothed. Tha carpus and manus are separate.
The metacarpals are separate and with digits. The pelvic girdle elements are free rather than co-ossified.
The iliac-blades are erect; the ischium is blade shaped; and the pubis seems directed ventrally, terminating in a hook-shaped foot as in Archaeopteryx.
The metatarsals are fused only at the proximal ends. Gastral ribs are present, as are several advanced avian traits.
The tail is short and a pygostyle is present. The shoulder joint permits raising of the wing above the level of the vertebral column.
The second digit of the manus and the ulna support flight feathers. The wing seems to have been capable of folding.
The manus is shorter than te forearm or the humerus. The hallux (thump) is opposable, and the fifth digit of the pes is absent.