Tianyunornis cheni: a new Hongshanornithid Ornithuromorph Bird From Lower Cretaceous China

New Information on Hongshanornithidae (Aves: Ornithuromorpha) from a new subadult specimen

Authors:

Zheng et al

Abstract:

We report a new species of basal ornithuromorph bird, Tianyunornis cheni gen et sp nov, based on a nearly complete and articulatd subadult individual from Lower Cretaceous Yixian Formation in the eastern region Nei Mongol, China. The new specimen shws Characeristic of the Hongshanornithidae (Hongshanornis longicreta, Longicrusavis houi, and Parahongshanornis chaoyanensis_, such as a small body size and elongate hindlimbs relative to their forelimbs, but it also possess some unique features that support the erection of a new genus and species, including a stright dentary (a simoidal dentary was previously considered an autapomorphy of hongshanornithids), teeth preserved on both the upper and lower jaws, sternal caudolateral trabecula has a distinct fan-shaped expended distal end. With the addition of this new taxon, Hongshanornithidae represents the most diverse recoginuzed clade of Early Cretaceous orinthuromorphs. The new specimen reveals new important morphological information regarding the Hongshanornithidae and confirms the controversial presence of teeth in this clade.