内蒙古上新世高特格地点的仓鼠化石(英文)  

NOTE ON THE CRICETIDS FROM THE PLIOCENE GAOTEGE LOCALITY,NEI MONGOL

作　　者：李强[1] 

机构地区：[1]中国科学院古脊椎动物与古人类研究所,脊椎动物进化系统学重点实验室,北京100044

出　　处：《古脊椎动物学报》2010年第3期247-261,共15页Vertebrata Palasiatica

基　　金：中国科学院知识创新工程重要方向项目(编号:KZCX2-YW-120);国家重点基础研究发展规划项目(编号:2006CB806400);国家自然科学基金项目(编号:40730210,40702004);现代古生物学和地层学国家重点实验室(中科院南京地质古生物研究所,编号:083106)资助

摘　　要：对历年来采自高特格地点3个不同层位的共227件仓鼠类标本进行了分类描述和研究,这些标本可以归入2属3种,分别为进步中华仓鼠Sinocricetus progressus,大中华仓鼠(新种)S.major sp.nov.和蒙古微仓鼠Nannocricetus mongolicus。作为内蒙古中部地区新近纪动物群序列中的最晚代表,上新世高特格动物群存在一些特有的进步的小哺乳动物种类,S.major新种就是仓鼠类中的一例。大中华仓鼠新种特征为:个体显著大,齿冠高,下臼齿发育有较发达的(假)下中脊,其中m1的下中脊指向前内方向,m2的假下中脊(或称下原尖后臂)前内向与下后尖后壁连接。古地磁的测定表明,Sinocricetus progressus和Nannocricetus mongolicus在高特格剖面上的年限大致为4.2～3.9Ma,S.major只出现于剖面下部,其年限约为4.2Ma.Sinocricetus和Nannocricetus两属目前主要发现于中国北方晚中新世早期至最晚上新世的地层中,它们可能都是中国特有的新近纪仓鼠。对内蒙古中部地区最晚中新世二登图和哈尔鄂博、早上新世比例克和高特格地点的材料对比表明,Sinocricetus牙齿特征可能存在如下演化趋势:M1-2原脊I发育频率逐渐增高,M1-2的中脊与后尖前壁连接的程度逐渐增高,m1下前脊从双支分别与唇舌两侧下前边小尖连接向单支与唇侧下前边小尖连接转变,以及m2的假下中脊与下后尖后壁发生连接的频率逐渐增高。Nannocricetus在其演化中牙齿形态变化可能存在的趋势是:M1-2的牙根数由3增加到4,M1-2的后小脊II逐渐退化消失,m1的下前边尖逐渐收缩变窄和分裂,M2-3和m2-3的舌侧(下)前边脊逐渐退化消失,及m3下中脊出现频率逐渐增高。Representing the youngest in the sequence of Neogene mammalian faunas in central Nei Mongol,the Gaotege fauna contains some derived taxa hitherto not known in the area. A total of 227 specimens of cricetids collected from three different levels of the Gaotege section are described and referred to 2 genera and 3 species,i. e. Sinocricetus major sp. nov.,S. progressus Qiu Storch,2000 and Nannocricetus mongolicus Schaub,1934. S. major sp. nov. is characterized by its large size,high crown with well-developed （pseudo）mesolophids on lower molars,and by having an anterolingually directed pseudomesolophid often connected to the posterior wall of the m2 metaconid. According to paleomagnetic correlation,S. progressus and N. mongolicus occur in the interval 4.2~3.9 Ma in the Gaotege section,whereas S. major sp. nov. occurs around 4.2 Ma. Thus far,Sinocricetus and Nannocricetus have been mainly found in the lower Upper Miocene to Upper Pliocene strata of northern China; they may therefore represent two endemic Neogene cricetini genera in China. In dental morphology,Sinocricetus exhibits the evolutionary trends of increasing frequencies of protoloph I development and connecting between mesoloph and anterior wall of metacone on M1-2,labially seated anterolophulid on m1,and connecting between pseudomesolophid and posterior wall of metaconid on m2. In Nannocricetus ,several inconspicuous dental morphological changes were observed,which include the increasing of root number from 3 to 4 on M1-2,reducing of the metaloph II on M1-2 and the lingual anteroloph（id） on M2-3 and m2-3,narrowing and splitting of the anteroconid on m1,and increasing frequency of mesolophid on m3.

关 键 词：内蒙古高特格 上新世 仓鼠 

分 类 号：Q915.873[天文地球—古生物学与地层学]