An Asian origin for Sinomastodon(Proboscidea, Gomphotheriidae) inferred from a new Upper Miocene specimen from Gansu of China  

作　　者：WANG ShiQi ZHAO DeSi XIE GuangPu SUN BoYang 

机构地区：[1]Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences [2]Gansu Industrial Occupational Technology College [3]Gansu Provincial Museum

出　　处：《Science China Earth Sciences》2014年第10期2522-2531,共10页中国科学（地球科学英文版）

基　　金：supported by Chinese Academy of Sciences(Grant No.XDB03020104);National Basic Research Program of China(GrantNo.2012CB821900);National Natural Science Foundation of China(Grant Nos.41372001,41002010,40730210);the Important Research Plan of IVPP

摘　　要：We report a fossil specimen referable to Sinomastodontinae gen. et sp. indet, from the Neogene strata at Yanghecun locality, Xihe County, Gansu Province, China. The specimen is characterized by a brevirostrine mandible, complete pretrite trefoils, and relatively simple posttfite half lophids, showing typical features of Sinomastodon. It differs from the other known species of Sinomastodon by the following features： relatively short and wide m3 due to fewer lophid numbers, less inflated pretrite ac- cessory central conules, poorly developed secondary trefoils and cementum, and relatively strong cingulid. All of these fea- tures indicate a bias towards pleisiomorphies of Sinomastodon, implying that this specimen is more ancestral than any known species of Sinomastodon. The symphysis of the new specimen is relatively long, which differs from the typical brevirostrine Sinomastodon, and thus we consider it a gen. et sp. indet, in the Subfamily Sinomastodontinae. In addition, the horizon in which the present specimen was found probably represents the Upper Miocene because it is lower than Pliocene strata yielding Hipparion （Proboscidipparon） pater. Generally, Sinomastodon is considered to have migrated from North America at about the time of the Miocene/Pliocene boundary, and to have been derived from a certain clade of American gomphotheres. However, the discovery of the Yanghecun specimen verifies that Sinomastodon lived in East Asia during the Late Miocene, and probably derived from Old World gomphotheres （e.g., G. wimani）. The similarity between the members of the Subfamilies Sinomastodontinae and those of Cuvieroniinae is suggested to have been the result of parallel evolution.We report a fossil specimen referable to Sinomastodontinae gen. et sp. indet. from the Neogene strata at Yanghecun locality, Xihe County, Gansu Province, China. The specimen is characterized by a brevirostrine mandible, complete pretrite trefoils, and relatively simple posttrite half lophids, showing typical features of Sinomastodon. It differs from the other known species of Sinomastodon by the following features: relatively short and wide m3 due to fewer lophid numbers, less inflated pretrite accessory central conules, poorly developed secondary trefoils and cementum, and relatively strong cingulid. All of these features indicate a bias towards pleisiomorphies of Sinomastodon, implying that this specimen is more ancestral than any known species of Sinomastodon. The symphysis of the new specimen is relatively long, which differs from the typical brevirostrine Sinomastodon, and thus we consider it a gen. et sp. indet. in the Subfamily Sinomastodontinae. In addition, the horizon in which the present specimen was found probably represents the Upper Miocene because it is lower than Pliocene strata yielding Hipparion(Proboscidipparon) pater. Generally, Sinomastodon is considered to have migrated from North America at about the time of the Miocene/Pliocene boundary, and to have been derived from a certain clade of American gomphotheres. However, the discovery of the Yanghecun specimen verifies that Sinomastodon lived in East Asia during the Late Miocene, and probably derived from Old World gomphotheres(e.g., G. wimani). The similarity between the members of the Subfamilies Sinomastodontinae and those of Cuvieroniinae is suggested to have been the result of parallel evolution.

关 键 词：Sinomastodon gomphotheres Sinomastodontinae Cuvieroniinae East Asia BIOSTRATIGRAPHY 

分 类 号：Q915[天文地球—古生物学与地层学]