New freshwater plesiosaurian materials from the Middle Jurassic Xintiangou Formation of the Sichuan Basin, southwestern China

作者：Feng Zhang,Hai-Dong Yu,Can Xiong,Zhao-Ying Wei,Guang-Zhao Peng,Xue-Fang Wei

摘要：Sichuan Basin is very famous for the Mesozoic reptiles, especially the Jurassic dinosaurs. Here, we report some isolated plesiosaurian teeth and vertebrae newly excavated from the Middle Jurassic Xintiangou Formation in Yunyang county, Chongqing City, the northeastern region of the Sichuan Basin, southwestern China. The specimens are referred to Pliosauroidea based on the combination of the following features: the circular cross-section of the tooth crown, apicobasal ridges fully covering the enamel surface and reaching to the apex, the short and amphicoelous centrum, the centrum shorter than wide or tall, and the absence of a keel on the lateral surface of the cervical centrum. With the fragmentary nature, it is undetermined whether the Yunyang specimens belong to a known taxon or represent a new species of Plesiosauria. These plesiosaurian specimens further demonstrate that the freshwater plesiosaurians are common in the Jurassic deposits of the Sichuan Basin. For a comprehensive knowledge of the plesiosaurians of the basin in origin, distribution and diversity, to discover new and more complete specimens is necessarily the first priority.

发文机构：Chongqing Laboratory of Geoheritage Protection and Research Zigong Dinosaur Museum Institute of Geology China University of Geosciences（Beijing） Cores and Samples Centre of Natural Resources

关键词：PlesiosauriaPliosauroideaMiddleJurassicXintiangouFormationSichuanBasin

分类号： P61[天文地球—矿床学]