河北蔚县大南沟晚更新世草原猛犸象(长鼻目|哺乳动物纲)

在泥河湾盆地真象化石十分常见。  近年来，在泥河湾层中新发现了世界上最早的草原猛犸象(Mammuthus trogontherii)化石，过去被归入古菱齿象的部分材料也被转移到该种；  但以往报道的材料都很零碎，并且时代也较早。本研究的发现于蔚县大南沟东陡壁附近的长鼻类下颌骨(完好下颌体带左右m3)亦可归入该种，主要依据如下特征: 喙突(或吻突)不发育、下颌联合部短、下颌体前缘陡直、具有舌侧神经孔、颊齿齿板中间突不发育和釉质环无菱形结构、下第三臼齿有×18个齿板、齿板较薄、齿板频率为6、釉质层较薄但褶皱不强烈等。蔚县大南沟的化石是迄今在我国所发现的材料最完好和地质时代最晚的草原猛犸象化石记录，距今约4.5万年。

NEW MATERIALS OF Mammuthus trogontherii(PROBOSCIDEA,MAMMALIA) OF LATE PLEISTOCENE AGE FROM YUXIAN,HEBEI

Elephantid fossils are among the most frequently appearing taxa in Nihewan Basin; recently,the earliest record of Mammuthus trogontherii of the world was identified in the Basin,and some other materials once referred to other genera were also transferred to this species. Nevertheless,the fossil materials are still fairly poor. The present paper deals with a nearly complete mandible with two m3s in situ,which was recovered from the sediments redeposited on top of the Nihewan beds of Early Pleistocene age. The exact location of the new fossil locality is near the famous profile of the Plio-Pleistocene deposits at Danangou,whose geographic coordinates are 40°05'31.3″N,114°43'34.3″E. The mandible can be referred to Mammuthus trogontherii according to the following characters: the rostrum or anterior process of the mandibular symphysis is short; the lateral view of the mandible is rectangular in shape; there exists a medial mental foramen on the lingual wall of the mandible near the symphysis; molars are stenocoronine; hypsodonty index(HI)is 150; the grinding surface of the molar plates is not lozenge-shaped; with ×18 plates on m3; the lamellar frequency is 6; enamel is 2～3mm in thickness and finely wrinkled. The fossil represents the most complete material and the latest occurrence of the extinct species Mammuthus trogontherii in China,whose U/Th date is around 45kaB.P.