记辽宁早第三纪一哺乳动物化石  

AN ANTHRACOTHERE LOWER PREMOLAR FROM LIAONING

作　　者：周明镇[1] 王元青[1] 

机构地区：[1]中国科学院古脊椎动物与古人类研究所

出　　处：《古脊椎动物学报》1991年第4期323-326,共4页Vertebrata Palasiatica

摘　　要：长期以来,东北广大区域内未曾发现过第三纪哺乳动物化石.1984年,在吉林桦甸第一次发现了一个晚始新世哺乳动物化石地点(王伴月、李春田, 1990).1988年,辽河油田秦德荣同志将一件哺乳动物化石送交中国科学院古脊椎动物与古人类研究所鉴定.这是辽宁首次发现的第三纪哺乳动物化石.标本发现于辽宁沈阳以西大约37.This paper reports the first occurrence of Tertiary mammalian fossil, an anthracothere lower premolar, from an oil well core at depth of 1739 m of the drill Fa-24 in Liaohe Oilfield, which situates about 37.5 km west to the city of Shenyang (Mukden), Liaoning Province. The specimen came from the upper part of Member 3 of Shahejie Formation, a set of grey silty mudstone and pelitic siltstone. The premolar, probably P_3, is tentatively ascribed to Anthracotheriidae gen. et sp. indet. (fig. 1). Description This premolar (Liaohe Oilfield specimen, number LHJ0001), double rooted, has a greatly compressed crown, trianguloid in side view, with a central Principal cusp. The ridges from the principal cusp have a convex slope in front, and a concave slope behind. The anterior part of the front ridge curves inwards. On the inner side, a faint distinct ridge is down from the summit of the cusp and meets the base about one third of the way between the posterior and anterior ends. A distinct lingual cingulum extends from posterior end to anterior one. Numerous striae cover all over the crown. The crown is almost unworn, but the small wearing facets are present on the antero-external side and the apex of the posterior ridge. Discussion Based on the characters of the specimen: obvious wearing facet anterior to the cusp, great compression of the crown, large size and faint inner ridge, etc., the premolar from Liaoning is probably the third left lower premolar (P_3). The specimen shows some resemblances to some Eocene and Oligocene anthracotheres, such as Anthracothema, Anthracokeryx, Anthracotherium and Bothriodon, but obviously differs from them. The relatively great length, faint inner ridge and nonseleodont principal cusp of this premolar probably indicate that it is not very late in age. Because it has some similarities to the forms of Pondaung, Burma, we tentatively consider its geological age to be of Late Eocene, or Early Oligocene. According to the fish fossils, the geological age of the bottom of Member 3 and the top of

关 键 词：辽宁 早第三纪 哺乳动物化石 石炭兽 

分 类 号：Q915.87[天文地球—古生物学与地层学]