THE SYSTEMATIC STATUS OF HANOSAURUS-HUPEHENSIS (REPTILIA, SAUROPTERYGIA) FROM THE TRIASSIC OF CHINA

Hanosaurus hupehensis was believed to represent a Middle Triassic thal attosaur from the People's Republic of China. Redescription of the hol otype and only known specimen, and cladistic analysis of its interrela tionships, shows Hanosaurus to represent a distinct pachypleurosaur. T he two Chinese pachypleurosaurs, Keichousaurus and Hanosaurus, form tw o consecutive sister-groups to European pachypleurosaurs, strengthenin g the Asiatic affinities of the clade. Addition of Hanosaurus furtherm ore results in a modification of pachypleurosaur interrelationships as previously reconstructed: the pachypleurosaurs from the Germanic Tria ssic (Anarosaurus, Dactylosaurus) form a monophyletic clade, which is sister-group to the monophyletic clade of Alpine pachypleurosaurs (Ser pianosaurus, Neusticosaurus). Thalattosauria are the sister-group of S auropterygia, the two clades possibly representing a single invasion o f the Mesozoic sea. However, more detailed knowledge of thalattosaur a natomy is required to further test the phylogenetic relationships of t halattosaurs.