India as a "Noah's Ark" before Collision with Eurasia: Palaeoenvironment and Palaeobiogeography of the Continental Early Eocene Vertebrate Fauna of Gujarat

Summary. — For the past twenty years, an Indian-American-Belgian team carried out twelve seasons ofcollaborative fieldwork in search of vertebrates from the Cambay Formation in lignite mines of Gujarat,western India. Here is a summary of our main discoveries in the Vastan, Mangrol, and Tadkeshwar mines,including an updated overview of the whole vertebrate fauna. The fauna is around 54.5 million years old,representing tropical rainforest conditions in a coastal brackish palaeoenvironment. It includes the earliestmodern mammals from the Indian subcontinent as well as endemic taxa. The most important result at thepalaeobiogeographical level is the discovery of several vertebrate taxa of Gondwanan affinities, indicatingthat the early Eocene was a crucial period in India when Laurasian taxa with western European affinitiesco-existed with relict taxa from Gondwana before the actual collision of India and Eurasia. Terrestrial faunascould have dispersed to or from Europe when the Indian subcontinent came into contact, episodically, withdifferent island blocks, such as the Kohistan-Ladakh island-arc system, along the northern margin of NeotethysOcean.