ABSTRACT
The Indian Peninsula is a compact natural unit of geomorphological and biogeographical evolution, and this phenomenon is exhibited with the distribution of fauna from Madagascar and tropical East Africa as well as a considerable number of Indo–Chinese and a small number of Malayan forms in Peninsular India, in addition to its own assemblage of many groups of animals. Indian landmass after collision with the Eurasian landmass, a significant biotic interchange of faunal groups took place, with India being a both biotic “ferry” and biotic “sink.” This hypothesis of “Out of India” and “Into India” is often used to explain patterns of distribution among Southeast Asian taxa. The present-day disjunct distribution of a large assemblage of genera and species of Malayan affinities has long attracted the attention of naturalists and efforts have been made to explain the causes of similarities. One well-known explanation for this is the Satpura Hypothesis of Sunderlal Hora (1949). The Western Ghats (WG) is the home for many of the original Gondwana relicts, the autochthonous fauna of Peninsular India, the transmigrants from the Palearctic and later Indo–Chinese and Malayan species and some Himalayan reflects which reached Peninsular India during the glacial periods have found refugium in the WG.
