The second mamenchisaurid dinosaur from the Middle Jurassic of Eastern China

ABSTRACT

A new mamenchisaurid dinosaur, Anhuilong diboensis gen. et sp. nov. from the Middle Jurassic of Eastern China is reported here. The holotype consists of complete left humerus, ulna and radius of an individual. Comparative study and cladistic analysis shows this new taxon belongs to Mamenchisauridae and bears a unique combination of characters, such as low ratios of the average of the greatest widths of the proximal end, mid-shaft and distal end of the humerus/length of the humerus, total length of ulna to humerus and total length of radius to humerus; the lateral edge of the deltopectoral crest directs caudolaterally, the lateral accessory condyle on the craniodistal edge of humerus is more robust than the medial one, and the cross-sectional shape of the ulna at mid-shaft is elliptical with highest ratio of transverse to craniocaudal diameter among mamenchisaurids. Phylogenetically, Anhuilong is the sister taxon of Huangshanlong, and with Omeisaurus they together form the sister clade to all other members of Mamenchisauridae. Including Huangshanlong, two mamenchisaurids have been found in eastern China, and indicates that Mamenchisauridae was already a diverse sauropod clade in China by the Middle Jurassic.

KEYWORDS:

• Huangshan
• Eastern China
• Middle Jurassic
• Hongqin Formation
• Mamenchisauridae
• Anhuilong

Acknowledgments

The materials are collected by Han Li-Gang (deceased), from the Anhui Institute of Archaeology, to whom we express our sincerely respect. At the same time, we also appreciate the original collection unit of the holotype, the Cultural Relics Bureau of Shexian County (Shexian Museum).

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

This work was supported by the National Natural Science Foundation of China [41472020,41688103]; Non-Profit Sector Project, Ministry of Land and Resources of China [201511054].