内蒙二马营组发现的肯氏兽类

<正> 肯氏兽类在我国产出相当丰富,过去曾发现于山西二马营组的上部和新疆小泉沟群的下部,化石计有两属六种,时代均为中三迭世。近年,地质科学院程政武在陕西府谷县二马营组底部发现一十分完整的肯氏兽头骨,另立一新属,命名为戏楼沟陕北肯氏兽Shanbeikannemeyeria xilougouensis(尚未发表)。内蒙地区过去从一些破碎的牙齿及骨片上也确定过存在肯氏兽类。我所二、三迭纪组一九七六年野外工作期间在内蒙伊克昭盟准格尔旗布尔洞公社采到一具不完整的肯氏兽骨架(包括头骨),现报道如下。依据化石的

KANNEMEYERIA FOSSIL FROM INNER MONGOLIA

During the field work of 1976,a kannemeyerid skull was discovered together withseveral postcranial bones from Inner Mongolia by a team of IVPP.In comparison with kannemeyerids so far known from China the said skull seemsto be more closely related to Shanbeikannemeyeria xilougouensis(Cheng,in Press)infollowing characteristics.Its pre-orbital region is short,basicranial axis is short andcurved,and occipital plate is rather high.As the expanded squamosal extends muchforward,the occipital plate is extremely inclined.In spite of their similarities,there are still some differences between our specimenand S.xilougouensis.The posterior part of the skull of the new specimen is narrowerthan that of S.xilougouensis,the maxillary process is smaller,the foramen magnumand occipital condyle-are larger and the tusks are longer.So a new specific name,S.buerdongia,is given to the new specimens.Both S.xilougouensis and S.buerdongia were collected from the bottom layer ofEr-ma-ying formation,which is under the bed bearing Sinokannemeyeria-fauna.Theage of Sinokannemeyeria-fauna was recently affirmed to be Early Middle Triassic.Asthe case stands,Shanbeikannemeyeria shows much more similarities to Kannemeyeriaof the Cynognathus zone than to Sinokannemeyeria and Parakannemeyeria.So thelower part of Er-ma-ying formation is suggested here to be correspond to Cynognathuszone of South Africa.The age of Shanbeikannemeyeria might probably be Late EarlyTriassic.