陕西蓝田晚中新世灞河组沙鼠类化石

沙鼠是一类由早中新世米古仓鼠类 (myocricetodontines)演化而来的啮齿动物 ,现生的种类主要分布于非洲、阿拉伯半岛和亚洲干旱的沙漠—荒漠草原地区。其高阶元的系统分类尚未取得一致的意见 ,但古生物学者一般认为 ,沙鼠类动物自成一科 ,并可分为 3个亚科 :米古仓鼠亚科 (Myocricetodontinae)、裸尾沙鼠亚科 (Taterillinae)和沙鼠亚科 (Gerbillinae) (Jaeger,1 977;Tong ,1 989;Chalineetal.,1 977;Wessels,1 999)。我国的现生沙鼠共有 3属 7种 ,均属Gerbillinae亚科 ,主要分布于蒙新高原及其南邻地带(王应祥 ,2 0 0 3)。最早的化石记录是甘肃泉头沟中中新世的Mellalomysgansus和Myocricetodonplebius (邱铸鼎 ,2 0 0 1 )。在其他新近纪地点发现的有甘肃庆阳、瓦窑堡和灵台 ,山西榆社和内蒙古化德、高德格的Pseudomerionesabbreviatus (Teilhard ,1 92 6;Young ,1 92 7;Schaub ,1 934;李传夔 ,1 981 ;Fahlbuschetal.,1 983;郑绍华、张兆群 ,2 0 0 0 ;QiuandStorch ,2 0 0 0 ;李强等 ,2 0 0 3) ,以及甘肃宁县的Pseudomerionescomplicidens (张兆群 ,1 999)。Mellalomys和Myocricetodon属归入Myocricetodontinae,而Pseudomeriones属归入Gerbillinae。本文记述Myocricetodon和Abudhabia两属沙鼠 ,后者被归

GERBILLIDS FROM THE LATE MIOCENE BAHE FORMATION,LANTIAN,SHAANXI

This paper describes three new species of Gerbillidae in two genera - Myocricetodon lantianensis sp. nov., M. liui sp. nov., and Abudhabia baheensis sp. nov. from the late Miocene Bahe Formation at Lantian, Shaanxi Province. M. lantianensis and M. liui show relative similarity to M. plebius from the middle Miocene of Quantougou, Gansu and M. sivalensis from the middle Miocene Siwaliks, Pakistan in dental pattern, and were closely allied to the two Asian middle Miocene gerbils, respectively. Abudhabia baheensis is the first record of the subfamily Taterillinae in China, and is considered to be the most primitive species of the genus so far known. The Lantian gerbils represent the eastern extension of distribution of the two genera. Their presence not only indicates the close biogeographic affinities of East Asia with North Africa and Southwest Europe during the late Miocene, but also suggests the existence of an open and xeric region between eastern Asia and northwestern Africa, where interchange of small mammals, via the Arabian Peninsula took place.