A Middle Triassic thalattosaur (Reptilia: Diapsida) from Yunnan (China)

A thalattosaur is described from Yunnan Province in southern China for the first time. The specimen consists of an incomplete hindlimb and a caudal vertebral column. It comes from the Upper Member of the Gejiu Formation (Late Ladinian) and compares closely to the basal thalattosaur Askeptosaurus italicus from the Middle Triassic of Europe. Differences from A. italic-its are also apparent, though. These include a relatively primitive phalangeal formula of 2-3-4-5-4, a polygonal calcaneum, a fourth distal tarsal that is 2 times larger than the three others, and second and third caudal ribs that are cone-shaped and slant slightly anteriorly. The incomplete preservation of the specimen prevents erection of a new species. The material is thus provisionally identified as cf. Askeptosaurus. The discovery of cf. Askeptosaurus and other marine reptile fossils from the same locality indicates a new assemblage of Triassic marine tetrapods in China.