中国三叠纪纯信龙类化石研究及其对蛇颈龙起源的意义

A Study of The Triassic Pistosauroidea Fossils in China and ItsImplication for the Origin of Plesiosaurs

三叠纪纯信龙类与繁盛于侏罗纪和白垩纪海洋的蛇颈龙类关系密切。中国目前已在贵州、广西和云南的几处地点发现了三叠纪纯信龙类化石,有效命名4属4种。其中,宋氏清镇龙和东方广西龙化石标本极为破碎,分别出自贵州清镇中三叠统拉丁阶和广西武鸣下三叠统奥伦尼克阶地层;李氏云贵龙产自云贵交界中三叠统拉丁阶地层中,已经发现了近10件保存很完整的云贵龙化石;短吻王龙发现于贵州兴义中三叠统法郎组竹杆坡段地层。近年来我国西南地区多具保存精美的纯信龙类化石的发现,为揭示纯信龙类的形态特征、个体发育和系统演化提供了新的线索。大量保存完整的纯信龙类化石证据表明,中国西南地区是蛇颈龙祖先类型——纯信龙类演化的重要地区,这对研究蛇颈龙起源与演化有着重要的意义。

Triassic pistosauroids are closely related to the plesiosauria which flourished in the Jurassic and Cretaceous.The Triassic pistosauroidea were only found in Guizhou,Guangxi and Yunnan Province in China.So far,four genera of Pistosauroids were reported.Two genera found based on very fragmented material.Chinchenia sungi was collected from Middle Triassic in Qingzhen County,Guizhou Province.Kuangsisaurus orientalis was collected from Lower Triassic in Wuming,Guangxi Province.Yunguisaurus liae came from middle Triassic in Xingyi,Guizhou province and Fuyuan,Yunnan Province,is the only Triassic pistosauroid represented by multiple articulated specimens.Nearly ten complete articulated skeletons have been found.Wangosaurus brevirostris was found Middle Triassic in Xingyi,Guizhou province.Recently,more and more complete specimens of Pistosauroids are found in southwest China.It will be significant in revealing the morphological distinctions and ontogenetic variations and phylogeny of pistosauroids.These fossils show that the southwestern region of China is a key habitat of pistosauroids,the ancestor of plesiosauria,and are of great significance for the studies on the origin and evolution of plesiosauria.