A new species of Omeisaurus (Dinosauria: Sauropoda) from the Middle Jurassic of Yunyang, Chongqing, China

ABSTRACT

A new species of Omeisaurus, O. puxiani sp. nov., from the Middle Jurassic of Southwest China is reported. The holotype consists of partial articulated vertebrae, forelimb, hind limb and other materials of an individual. Comparative study and cladistic analysis show that this new taxon belongs to Omeisaurus, and bears a unique combination of character states, such as all presacral vertebrae opisthocoelous, complex pneumatic fossa system in middle cervical centra, lateral fossae of dorsal centra divided by secondary septa, end of anterior caudal neural spines expanding posteriorly, edge of humerus deltopectoral crest turning posterolaterally and ratio of length of ulna to humerus of 0.69. The previously reported single middle cervical (S66) from the same locality and horizon can be referred to this new species. The discovery of Omeisaurus puxiani enriches the diversity of the genus of Omeisaurus and provides additional information to help understanding the evolutionary history of this genus in Eastern China.

Abbreviations No. 208 HEGT: Chongqing Laboratory of Geological Heritage Protection and Research, No. 208 Hydrogeological and Engineering Geological Team, Chongqing Bureau of Geological and Mineral Resource Exploration and Development Chongqing, Chongqing, China; GSC: Chongqing Institute of Geological Survey, Chongqing, China; IVPP: Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China; ZDM: Zigong Dinosaur Museum, Zigong, Sichuan, China

KEYWORDS:

• Pu’an
• Chongqing
• Shaximiao Formation
• Middle Jurassic
• Sauropoda
• Omeisaurus

Acknowledgments

We are grateful to Wei Guangbiao and He Jianjun and the personnel of the Yunyang Dinosaur Administration for various help during this study, to Zhang, Yu-Qing, Han, Xiang-Song and others for preparing the specimen, to Li, Qi for helping photographing, to Ye, Yong and Hao, Bao-Qiao for providing information on Omeisaurus tianfuensis at Zigong Dinosaur Museum. Thoughtful reviews by Guillermo J. Windholz, Toru Sekiya, an anonymous reviewer, and the editor improved an earlier version of this manuscript.

Disclosure Statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study is supported by Project of Dinosaur Fossil Protection and Research of Chongqing Planning and Natural Resources Bureau (No. kj-2018035); The Strategic Priority Research Program of Chinese Academy of Sciences (Grant number: XDB26000000); National Natural Science Foundation of China (Grant numbers: 41688103, 41872021); Natural Science Foundation of Chongqing, China (No. cstc2018jcyjAX0435); Postdoctoral Project of Chongqing, China (No. Xm2017069).