中文摘要：

在对安徽巢湖马家山下三叠统南陵湖组地层的发掘中发现的早三叠世奥伦尼克期始鳍龙类一新材料，分支系统分析表明其与华南地区中三叠世肿肋龙亚目的滇肿肋龙和贵州龙关系密切。这是目前世界同期地点信息、层位信息准确且保存最好的早三叠世鳍龙标本。新材料与巢湖鱼龙和两种双孔类海生爬行动物伴生，表明在早三叠世晚期海洋生态系统出现了一次辐射演化事件，其海生爬行类的分异度较高。这一发现表明海洋生态系统在经历二叠纪末绝灭事件后在早三叠世的复苏迅速，与传统观点认为的复苏过程受海洋环境影响而延迟相反。

英文摘要：

Here we report a new eosauropterygian from the Early Triassic of Majiashan , Chaohu Fauna of Anhui Province.The phylogenetic analysis suggests it is close related to the Dianopachysaurus and Keichousaurus from the Middle Triassic of South China .This is hitherto the first and relatively well preserved Early Triassic saurop-terygian discovered with precise locality and stratigraphy information .The co-occurrence of sauropterygian along with Chaohusaurus and at least two species of diapsid suggests a radiation of the marine ecosystem during the Early Triassic and a high diversity among the marine reptiles.Contrary to the traditional of view of delayed recovery of the marine ecosystem during the Early Trias-sic, the high diversity among marine reptiles represents a rapid recovery barely affected by the environment .