Comments on the Pinjor Mammalian Fauna of the Siwalik Group in relation to the post-Siwalik faunas of Peninsular India and Indo-Gangetic Plain

Pinjor Mammalian Fauna, ranging in age from 2.58 to 0.6 Ma, is the youngest fauna of the Siwalik Group. The process of its extinction and migration started at 1.79 Ma and after 0.6 Ma there is no record of this fauna from the foothills of Himalaya. The post-Siwalik faunas are known from Peninsular India and Indo-Gangetic Plain. From Peninsular India two faunal horizons roughly of Middle Pleistocene and Upper Pleistocene ages are known. However from Indo-Gangetic Plain, only an Upper Pleistocene fauna is known. Pinjor Mammalian Fauna is very rich and comprised of 98 species. This fauna was widespread and during its time span migrated to the intermontane basins of Kashmir and Kathmandu. Both Peninsular and Indo-Gangetic faunas are scanty as compared with the Pinjor Fauna. Twenty one Pinjor genera are present in post-Siwalik deposits and these include six Pinjor species. Remaining 15 Pinjor genera with different species survived in post-Siwalik horizons of India. Thus Pinjor Fauna, on species level, shows gradual extinction and not the massive migration. Evidence indicates that about 45,000 years back along the present course of River Yamuna, there was at least a depression if not the presence of river, which acted as route of migration for the remnant faunas.