古脊椎动物学报（中英文）2024，Vol.62Issue(1)：13-32,20.DOI:10.19615/j.cnki.2096-9899.231013
云南中三叠世一恐头龙科小型主龙型类
A small-sized dinocephalosaurid archosauromorph from the Middle Triassic of Yunnan,southwestern China
摘要
Abstract
Among numerous marine reptiles discovered in the Triassic eastern Tethys,today's Southern China,Dinocephalosaurus is a bizarre animal comparable to European Tanystropheus in developing a prominently long neck.These two taxa are respectively assigned to Dinocephalosauridae and Tanystropheidae,and the two families and other basal members collectively form an early-diverging clade of Archosauromorpha.Here we report a new archosauromorph specimen,IVPP V18579,excavated from the lower Middle Triassic(Anisian),from Luoping,Yunnan in southwestern China.Compared with all the hitherto known dinocephalosaurids and tanystropheids,this skeletally mature individual is exclusively similar to Dinocephalosaurus in a number of characteristics,particularly with the long posterodorsal process of the premaxilla extending posteriorly beyond the level of the external nares,the concave posterior margin of the anteroposteriorly broad quadrate,and the strongly expanded distal end of the chevron in most of the caudal vertebrae.However,this reptile is much smaller than Dinocephalosaurus and different from Dinocephalosaurus and the other dinocephalosaurid,Pectodens,in many aspects,such as an anteriorly tapering long rostrum,the dentition composed of short conical teeth with less heterodonty,relatively but obviously tall neural spines of the axis and the anterior cervical vertebrae.Our phylogenetic analysis suggests that the new archosauromorph is a dinocephalosaurid,and then we erect Austronaga minuta gen.et sp.nov.based on this specimen.Detailed comparisons in osteological anatomy and the discussion about its potential aquatic adaptation of this new taxon are also provided.关键词
云南罗平/东特提斯/三叠纪/海生爬行动物/主龙型类/恐头龙科/骨骼学解剖Key words
Luoping,Yunnan/East Tethys/Triassic/marine reptile/Archosauromorpha/Dinocephalosauridae/osteological anatomy分类
生物科学引用本文复制引用
王维,雷洪,李淳..云南中三叠世一恐头龙科小型主龙型类[J].古脊椎动物学报（中英文）,2024,62(1):13-32,20.基金项目
中国科学院战略性先导科技专项(B类)(编号:XDB26000000)、国家自然科学基金(批准号:42002019)和中国科学院青年创新促进会资助.We are grateful to DING Jin-Zhao for the preparation and GAO Wei for the photographs of this fossil material.The discussion with Nicholas C.Fraser and Stephan N.F.Spiekman about the European specimens is appreciated.Two reviewers provided helpful comments that significantly improved our manuscript.This research was supported by the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB26000000),the Youth Innovation Promotion Association of Chinese Academy of Sciences,and the National Natural Science Foundation of China(42002019). （B类）
