Theropod and Ornithischian Footprints from the Middle Jurassic Yanan Formation of Zizhou County, Shaanxi, China

Abstract

New tracksites reported from the Zizhou area elucidate the nature of the Early-Middle Jurassic dinosaurian ichnofaunas in Shaanxi Province. The assemblage is composed of footprints and trackways of medium- to large-sized theropods that show similarities with both the ichnogenera Kayentapus and Eubrontes and of small bipedal ornithischians that are referred to AS Anomoepus isp. Additionally tracks of a quadruped are present and assigned to Deltapodus isp. that may be related to a stegosaurian. Anomoepus isp. is similar to the holotype of Shensipus tungchuanensis which is, although apparently lost, re-assigned here and considered to be a subjective junior synonym of Anomoepus. It is therefore placed in new combination as Anomoepus tungchuanensis comb. nov. Identical tracks have been reported from well-preserved trackways both in the Zizhou and Shenmu areas, where they also co-occur with theropod tracks (Kayentapus and Grallator) and tracks of quadrupedal ornithischians (Shenmuichnus and Deltapodus). Thus, it appears that the carbonaceous (coal-bearing) facies of the region reveal ichnofaunas with both relatively abundant saurischian (theropod) and ornithischian tracks. This is in contrast with many areas where the ichnofaunas are heavily or exclusively saurischian (theropod) dominated.

Keywords:

• Shaanxi
• Ordos Basin
• Dinosaur tracks
• Kayentapus
• Shensipus
• Anomoepus

ACKNOWLEDGMENTS

The authors thank Academician Degan SHU, Prof. Yongxiang LI (Northwest University, Shaanxi, China) and LI Jianjun (Beijing Museum of Natural History, Beijing, China) for their suggestions on an earlier version of the manuscript, as well as Adrian P. Hunt (New Mexico Museum of Natural History, USA) and Richard T. McCrea (Peace Region Palaeontology Research Centre, Canada) for their constructive reviews. Thanks to Junmin Gao and Shurong Dong (Yulin municipal society for private collections culture, Shaanxi, China), and Guo Qiming from Institute of Geological Survey, Shaanxi Province, who provided logistic support.

FUNDING

This research was supported by Bureau of Land and Resources, Zizhou County and Yulin Municipal Society for Private Collections Culture, Shaanxi, China.