西藏阿里门士的真马化石  

DISCOVERY OF FOSSIL EQUUS NEAR MENSHI(MOINCER,OR MENCI),NGARI,XIZANG(TIBET)

作　　者：李强[1] 王世骐[1] 颉光普[2] 

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 [2]甘肃省博物馆,兰州730050

出　　处：《第四纪研究》2011年第4期689-698,共10页Quaternary Sciences

基　　金：中国科学院知识创新工程重要方向项目(批准号:KZCX2-YW-Q09);国家自然科学基金项目(批准号:40702004和40730210);美国自然科学基金项目(批准号:EAR-0958704和0958602);美国国家地理Waitt基金项目(批准号:W 22-08)资助

摘　　要：描述了2009年采自西藏阿里地区门士乡附近的2件真马化石,标本包括1件完整的右前第2指节骨和1件左第3蹠骨近端,均采自门士河右岸河湖相砂砾岩堆积中。标本粗壮,第3蹠骨近端关节面圆隆、对各跗骨关节面宽大,第2指节骨横宽。大小形态上与邻近的札达盆地上新世地层中的札达近三趾马Hipparion(Plesiohipparion)zandaense者截然不同,代表了一类比现生半驴Equus kiang和E.hemionus都要大的真马类,可能属于普氏野马E.przewalskii。真马化石的发现确定了门士河右岸的河湖相砂砾岩为第四纪沉积物,已知E.przewalskii出现的时间通常不早于晚更新世,如果以后能增加标本证明门士真马化石确实属于E.przewalskii,那么门士的这套河湖相地层的形成年代应不早于12.6万年。During the 2009 fieldwork season our team discovered several equid fossils near Menshi（Moincer, or Menci） town, Ngari, Xizang （Tibet）, adjacent to the Neogene Zanda Basin which yielded Palaeotragus microdon and Hipparion （Plesiohipparion） zandaense （Fig. 1 ）. Fossil equids were collected from a series of fluviolacustrine sihstone,sandstone and conglomerate sediments exposed on the west bank of Menshi River, ca. 5km northwest of Menshi town. New materials include a proximal portion of left third metatarsal（V18033） and a well preserved right second phalanx（V18034）（ Fig. 3 ）,which were collected from field sites MS0901 （31°12′41.6″N,80°42′42.5″E） south of national highway G219 and MS0902 （ 31 °13′26.2″N, 80°44′46.6″E） north of G219, respectively （ Figs. 1 and 2）. For comparison,we took measurements 5 - 9 for the metatarsal and 1- 6 for the second phalanx of Equus based on Eisenmann et al. （1988）（ see Tables 1-2）. In size, the materials from Menshi are distinctly larger than those of large-size Hipparion such as H. （ Proboscidipparion ） pater, H. （Plesiohipparion） zandaense, H. （ Pl. ） houfenense and H. （ Hipparion ） hippidiodus, and also larger than those of hemiones including both Equus hemionus and E. kiang （Figs. 4 and 5 ）. In morphology, the attribution possibility to Hipparion and hemiones is excluded based on the fact that third metatarsal has a wide and thick articular facet for the Os tarsale tertium （ Fig. 3 ）. Compared with those of 7 comparable species of Equus with known limb bone material in China,the Menshi sample is closest to that of E. przewalskii both in size and morphology. However,the Menshi sample is here treated as an indeterminate species of Equus given the lack of more diagnostic elements such as skull or dentitions. The fossil E. przewalskii were widespread in the Late Pleistocene Eurasian strata. In China, E. przewalskii from Dingcun fauna represents its earliest appearance at about 0. 12 ~ O. 10M

关 键 词：西藏门士 第四纪 真马 

分 类 号：P534.631[天文地球—第四纪地质学] Q915.87[天文地球—古生物学与地层学]