CRETACEOUS BIVALVES OF KANGPA GROUP SOUTH XIZANG CHINA AND THEIR BIOGEOGRAPHY^∗

In this paper42bivalve taxa including10new species recovered from the Kangpa Group of South Xizang （Tibet） are described．Most of them come from the middle and lower parts of the group which is Aptian-Albian in age and theothers from the upper part belonging to Cenomanian-Coniacian in age．The fauna of the middle and lower parts bearing endemic genera Astartoides and Yoldioides and numerous endemic species （about 61%）marks the existence of an endemiccentre．It is distinctly different from that of the area on the north of the Yarlung Zangbo River Suture Zone which shows closerelation with that of Eas Asia West Asia and Europe．In the meantime some of Australian characteristic genera such as Eyrena Maccoyella and Nototrigonia and a number of such species （about29%） are found from the middle and lower partsof the Kangpa Group which are recorded in Northern Hemisphere for the first time．This fact indicates that the Indian Subcontinent had already started its drifting northward but the drift distance should be not far from Antarctica-Australia in Aptian-Albian with the fauna of the Kangpa Group living in the north epicontinental sea of the subcontinent still could maintain the relation and exchange with that of Australian bivalves in spite of the fauna with a strong local colour．

Project Supported:

Clc Number:

Q915