A lariosaur (Reptilia : Sauropterygia) from the Middle Triassic (Ladinian) Gejiu Formation of Yunnan, China

摘要

A partial nothosaurid skeleton, consisting of two nearly complete forelimbs, part of the shoulder girdle and part of the trunk is described from the upper member of the Gejiu Formation (upper Ladinian) of Yunnan Province, SW China. It is referred to Lariosaurus based on the following characters: the dorsal ribs are pachyostotic, the ulna is prominently broadened and somewhat longer than the radius, there are five carpal ossifications, the humerus is evenly curved with no distinct constriction in its mid-diaphyseal region, hyperphalangy is present in the marms. The incomplete preservation of the specimen prevents a specific assignment, so that it is identified as Lariosaurus sp.. The discovery of Lariosaurus sp., cf. Askeptosaurus, and other marine reptile fossils from the same locality in northern Yunnan indicates a new, important and diverse assemblage of Triassic marine reptiles in SW China.