古脊椎动物学报2022，Vol.60Issue(4)：249-270,22.DOI:10.19615/j.cnki.2096-9899.220524
云南罗平中三叠世安尼期鳍龙类Nothosaurus—新种
Nothosaurus luopingensis sp.nov.(Sauropterygia)from the Anisian,Middle Triassic of Luoping,Yunnan Province,China
摘要
Abstract
Nothosaurus luopingensis sp.nov.from Member Ⅱof the Guanling Formation(Anisian,Middle Triassic)of Luoping,Yunnan,China is described based on a specimen comprising the skull and most of the postcranial skeleton.The specimen is assigned to Nothosaurus of Eosauropterygia as suggested by a series of skull characters,such as the maxillary tooth row extending posteriorly beyond the level of the anterior margin of the upper temporal fenestra,the longitudinal diameter of the upper temporal fenestra more than twice as long as that of the orbit,and the presence of maxillary fangs.Compared with Lariosaurus,the following morphological features of the pectoral girdle and the limbs also support the assignment of the specimen to Nothosaurus,i.e.,the clavicles with expanded anterolateral corners,the characteristically curved humerus with a straight preaxial angle and a postaxial concavity,the distinct deltopectoral crest on the proximal part of the humerus,no hyperphalangy in the manus,and the absence of pachyostosis in the vertebrae and ribs.On the other hand,the specimen possesses some postcranial features that were previously considered to occur mainly in Lariosaurus,such as more than three ossifications in the carpus,four sacral ribs,and an interclavicle without any trace of a posterior stem.These postcranial characters may no longer be used as the diagnostic features of Lariosaurus.Nothosaurus luopingensis is distinguished from other Nothosaurus species by a unique combination of derived characters,including that the jugal enters the orbit,the nasals are separated,the posterior end of the frontal is bifurcate,pedal digits V and IV are long and subequal in length,and the ungula phalanx is stout.Our phylogenetic analysis corroborates the monophyly of Nothosaurus and suggest that N.luopingensis is the sister group of N.yangjuanensis.关键词
云南罗平/中三叠世安尼期/始鳍龙类/幻龙属Key words
Luoping,Yunnan,China/Middle Triassic,Anisian/eosauropterygian/Nothosaurus分类
生物科学引用本文复制引用
尚庆华,李淳,王维..云南罗平中三叠世安尼期鳍龙类Nothosaurus—新种[J].古脊椎动物学报,2022,60(4):249-270,22.基金项目
中国科学院战略性先导科技专项(B类)(编号:XDB26000000)和国家自然科学基金(批准号:41772006,41372028)资助.We are very grateful to Chen Yin-Fang and Ding Jin-Zhao for the preparation of the materials and to Gao Wei for the photographs.This study was financially supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB26000000)and the National Natural Science Foundation of China(NSFC Grants No.41772006,41372028). （B类）
