Chupkaornis is a genus of prehistoric flightless birds from the Late Cretaceous (Coniacian-Santonian) Kashima Formation of Hokkaido, Japan.
Diagnostic traits of Chupkaornis include a finger-like projected tibiofibular crest of femur, deep, emarginated lateral excavation with a sharply defined edge of the ventral margin of the thoracic vertebrae, and the heterocoelous articular surface of the thoracic vertebrae.[1]
Chupkaornis is recovered by Tanaka et al. (2017) as more derived than the Cenomanian-age form Pasquiaornis, but less advanced than Brodavis and Baptornis.[1]