西藏聂拉木县聂聂雄拉地区早、中侏罗世双壳类动物群

西藏聂拉木县聂聂雄拉地区，早、中侏罗世地层较发育，地层中化石属 种繁多。地层划分为下侏罗统“普普嘎组”，中侏罗统聂聂雄拉组和拉弄拉组。作者研究了该区旱、中侏罗世的双壳类动物群40多属80多种。描述双壳类化石8新种：Tancredia(T.)nyalamensis,Hiatellasubtrigona,Pronoella(P.)minima,Opis(O.)curvus,Costigeruillia tetracostata,Weyla costalliformisa,Entolium obliquus,E.subfilosus,刊出部分化石图版，简述双壳类化石组合特征。它的研究对该地区旱、中侏罗世地层划分对比，生物地理分区和动物群特征的认识都具有一定的理论与实践意义。

A BIVALVE FAUNA OF EARLY AND MIDDLE JURASSIC EPOCH IN NIENIEXIONGLA REGION, NYALAM COUNTY, TIBET

The strata of early and middle Jurassic epoches are relatively developed in Nieniexiongla region, Nyalam County, Tibet, with various genera and species of fossils. The strata are divided into three formations: Pupuga Formation of lower Jurassic series, Nieniexiongla and Lalongla Formation of middle Jurassic series. This paper further makes a study of the rich bivalves fauna (more than 40 genus and 80 species) of early and middle Jurassic epoches in this area, describes 8 new species ( Tancredia (T.) nyalamensis, Hiatella subtrigona, pronoella (P.) minima, Opis (O.) curvus, Costigervillia tetracostata, Weyla costalliformisa , Entoliam obliquus, E. subfilosus ) and publishes parts of fossil bivalve photos. In addition, a brief account is also given on the characteristics of fossil bivalve assemblages. This study should be of theoretical and practical significance to subdivision and correlation of the early and middle Jurassic strata, to biogeographical subregion, and also to the understanding of faunal characteristics in this area.