VERTEBRATE BIOGEOGRAPHIC EVIDENCE FOR CONNECTIONS OF THE EAST AND SOUTHEAST-ASIAN BLOCKS WITH GONDWANA

A review of the fossil-vertebrate literature indicates fluctuating aff inities between aquatic faunas of China and Australia during the Devon ian Period. Within the South China Block, the close similarity of the highly endemic freshwater fish faunas located on the Yangtze and Huana n terranes demonstrate that these must have been juxtaposed in the mid -Palaeozoic. Analysis of the Triassic tetrapods suggests the faunas of Australia were quite distinct from those of China and Thailand. Altho ugh this evidence points to the Permo-Carboniferous as the time of sep aration between Australia and the various plates of southeastern Asia, unfortunately the vertebrate fossil record in these regions during th ose periods is so poor as to shed no direct light on the matter. One o f the problems of plate motion where fossil vertebrate evidence has co ntributed the most is the Mesozoic position of India. Because the rele vant data are of a positive nature rather than dependent on the absenc e of taxa, the inference from them that there was substantial faunal i nterchange between the subcontinent and more northern regions of Asia by the Late Cretaceous is well established.