Review of the Cretaceous dinosaurs from India and their paleobiogeographic significance

Abstract

The Indian Mesozoic dinosaur record is famous for documenting significant aspects of dinosaur evolution during the Triassic, Jurassic and Cretaceous periods. The Cenomanian–Turonian Nimar Sandstone, Lower Narmada valley, has produced fragmentary skeletal remains of Sauropoda indet. The Maastrichtian Lameta Formation has yielded at least 6 valid sauropod taxa and indeterminate titanosaurid remains, and at least 11 named (but likely oversplit) theropod taxa, i.e., 3 smaller-bodied species and 8 medium-to-large sized theropods. Apart from skeletal remains, Infra- and Intertrappean beds of peninsular India have yielded more than 10,000 dinosaur eggs belonging to 5 oofamilies and 15 oospecies. Most of the Indian ootaxa show distinct affinities with the Late Cretaceous ootaxa of four other continental areas – Spain, France, Argentina and Morocco. The presence of the two dominant oofamilies, Fusioolithidae and Megaloolithidae, in the Infra- and Intertrappean localities of peninsular India and three different continents (South America, Europe and Africa) further shows an ancient Gondwanan affinity and basic terrestrial association among these three landmasses. Based on the phylogenetic analysis of skeletal material, the most plausible pathway of dinosaur dispersal between India and Madagascar took place during the Late Cretaceous. The other conceivable dispersal pathway for the small animals was between India and Asia by means of the Kohistan Dras Volcanic Arc or a northeast pathway through Somalia, while the very large vertebrates, like theropod dinosaurs, may have emerged as a component of a ‘Pan Gondwanan’ model.