虔州豫俊兽(Yubaatar qianzhouensis sp.nov.):江西赣州盆地首例晚白垩世哺乳动物化石  

A new multituberculate,Yubaatar qianzhouensis sp.nov.:the first Late Cretaceous mammal from Ganzhou Basin,Jiangxi Province

作　　者：胡金锋 韩凤禄[1] HU Jin-feng;HAN Feng-lu(School of Earth Sciences,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉),地球科学学院,武汉430074

出　　处：《古生物学报》2021年第4期565-579,共15页Acta Palaeontologica Sinica

基　　金：国家自然科学基金(41688103)资助。

摘　　要：本文报道了产自江西省赣州市上白垩统赣县河口组的一件多瘤齿兽类标本,这是江西省报道的首例中生代哺乳动物化石。此标本头骨后部横向扩展,额骨较小,后端尖并构成眼眶的内侧边缘,M1具三列齿尖,系统发育分析支持其归入纹齿兽超科。与河南晚白垩世的中原豫俊兽形态较为相似,但是两者间也存在一些明显的区别,因此建立一个豫俊兽属新种——虔州豫俊兽(Yubaatar qianzhouensis sp.nov.),鉴定特征为:m1齿尖式为7︰6;M2齿尖式为1︰3︰3;m1颊侧后部存在一道小脊;虔州豫俊兽m2和m1的长度比例小于中原豫俊兽;冠状突呈楔状,末端尖。虔州豫俊兽的发现不仅扩展了晚白垩世多瘤齿兽类在东亚地区的地理分布和物种多样性,并且也扩展了中生代哺乳动物的地理分布。The Multituberculata represents one of the most successful groups of mammals that lived in the Mesozoic and early Cenozoic.More than 10 genera have been reported from North China,but there are still no records of this group from South China.Ganzhou Basin in Jiangxi Province has been reported to be rich in vertebrate fossils,but no mammals have previously been found there.Here,we report a new multituberculate,Yubaatar qianzhouensis sp.nov.,from the Upper Cretaceous Hekou Formation of Ganxian County,Ganzhou City,Jiangxi Province,China.This taxon represents the first known multituberculate from South China.The holotype of Yubaatar qianzhouensis preserves the posterior region of the skull and part of the postcranial skeleton.The posterior part of the skull is laterally expanded,giving the skull a square-like shape.A triangular process is formed by the frontals and projects posteriorly between the parietals.The lower jaw is in tight occlusion with the skull,concealing the occlusal surfaces of the teeth.Therefore,the skull was CT scanned,and the teeth were reconstructed using the software Mimics 19.0.The postcranial skeleton includes both forelimbs,the right scapula,and some ribs and lumbar vertebrae.In general,our new specimen is quite similar to Yubaatar zhongyuanensis from the Upper Cretaceous of Henan Province,and can be assigned to Yubaatar based on the following characters:the frontals are pointed posteriorly and contribute to the medial rims of the orbits;the coronoid process is low and short;the angle between the anterior margin of the coronoid and the molar part of the alveolar margin of the mandible is greater than 45°;the molars lack cusp ornamentation;M1 possesses three cusp rows,and the lower molar cusps are nearly uniform in height.However,our new species can also be distinguished from Yubaatar zhongyuanensis by a combination of characters:the m1 cusp formula is 7︰6;the M2 cusp formula is 1︰3︰3;m1 bears a posterobuccal cingulid;the m2/m1 length ratio is smaller than that of Y.zhongyuanensis;and the

关 键 词：上白垩统 赣州 多瘤齿兽目 纹齿兽超科 豫俊兽属 

分 类 号：Q915.2[天文地球—古生物学与地层学]