Cretaceous vertebrate fauna of the Cauvery Basin, southern India: Palaeodiversity and palaeobiogeographic implications

• Marine and non-marine vertebrates occur in Cretaceous sequences of Cauvery Basin.
• Marine vertebrates show a wide geographic distribution and a vast marine territory.
• Non-marine vertebrates show mixed Gondwanan and Laurasian affinities.
• Fauna indicates close links between India and Madagascar in the latest Cretaceous.

The vertebrate fauna from the late Albian to Maastrichtian succession of the Cauvery Basin, south India has been known since 1845, but it received only scant attention as compared to the vertebrates already known from the Deccan volcanic province of peninsular India. Recent fossil discoveries appear to support the emergence of significantly diverse marine and non-marine vertebrates comprising fishes, frogs, reptiles (ichthyosaurs, plesiosaurs, turtles, crocodiles and dinosaurs) and a mammal from the Cauvery Basin have revived the interest in the fauna of the basin as it has significant implications for understanding the palaeobiogeography of India. The latest Albian to Turonian marine vertebrates such as sharks, ichthyosaurs and plesiosaurs show a wide geographic distribution and marine territory, while sharks are typically cooler water fauna of high palaeolatitudes. The latest Maastrichtian non-marine vertebrates especially turtles, crocodiles, dinosaurs and a mammal are considered to show mixed Gondwanan and Laurasian affinities thus providing new lines of evidence in favour of a latest Cretaceous biotic links between India and the neighbouring continents. An overview of the vertebrate faunal diversity of the Cretaceous sequences of the Cauvery Basin and its palaeobiogeographic considerations are presented.