Yen-Nien Cheng

Tamaki Sato, Chun Li, Xiao-Chun Wu

Academic paper

Journal of Vertebrate Paleontology

26

2

201-504

Triassic pistosauroids (Reptilia: Sauropterygia) are the closest relatives of the Plesiosauria, a group that achieved considerable taxonomic diversity and cosmopolitan distribution during the Mesozoic. Despite their importance for the understanding of the origin of the Plesiosauria, however, our knowledge on the Triassic pistosauroids (Augustasaurus Sander et al, 1997; Chinchenia Young, 1965; Corosaurus Case, 1936; Cymatosaurus Fritsch, 1894; Kwangsisaurus Young, 1959; Pistosaurus Meyer, 1939; Edinger, 1935; Rieppel, 1997, 1998, 1999; Storrs, 1991) has been limited due to the lack of well-preserved specimens. We report a new pistosauroid, Yunguisaurus liae gen. et sp. nov., from the Triassic of southern China. This taxon is represented by a virtually complete and articulated skeleton embedded in a limestone slab from the Falang Formation (upper Middle to lower Upper Triassic). Previously described Triassic pistosauroids are known from the upper Lower to lower Middle Triassic (Rieppel, 1999, 2000; Wang et al., 2001), and Y. liae is the youngest pistosauroid (excluding the Plesiosauria). Because of the rarity of pistosauroids, we are providing this preliminary report while the postcranial skeleton waits for further preparation and subsequent full description. A unique combination of primitive and derived traits is observed in this specimen, and a phylogentic analysis confirms its close relationship with derived pistosauroids.

English