A new Chengyuchelys latimarginalis record from the Upper Jurassic Shangshaximaio Formation of Sichuan Basin, China, and the intraspecific variation.

A new Chengyuchelys latimarginalis (Xinjiangchelyidae) specimen is reported based on a well-preserved, nearly complete shell from the upper part of the Upper Jurassic Shangshaximiao Formation of Qijiang District, Chongqing Municipality, China. The Xinjiangchelyidae were widely distributed in Asia during the Jurassic and were the dominant turtle group in Asian freshwater ecosystems during the Late Jurassic. The Qijiang specimen adds a new element to the yet poorly known freshwater vertebrate fauna and extends the geographical distribution of C. latimarginalis. This paper discusses the intraspecific variation in C. latimarginalis for the first time. It provides a new insight for studying the evolution, habitat, and diversity of xinjiangchelyids. [ABSTRACT FROM AUTHOR]