Additional late Miocene sharks and batoids (Chondrichthyes, Elasmobranchii) from Baripada Beds, Odisha, India: Implications for palaeoenvironment and palaeobiogeography

The marine fossiliferous Baripada Beds (Upper Miocene), on the eastern coast of India, are well known for yielding diverse species of sharks, batoids and teleost fishes, reptiles, mammals, invertebrates and microfossils (Foraminifera and Ostracoda). A recent study conducted at Mukurmatia and Itamundia localities yielded more than 200 additional specimens of shark and batoid teeth from these rocks. A total of nine families of sharks and batoids belonging to Carcharhinidae, Hemigaleidae, Alopiidae, Myliobatidae, Dasyatidae, Pristidae, Rhynchobatidae, Rajidae, and Sphyrnidae have been recorded from Mukurmatia and Itamundia localities. The present study also records additional elasmobranch species ( Carcharhinus amblyrhynchoides, C. brevipinna, C. perezi, C. plumbeus, Physogaleus hemmooriensis, Physogaleus sp., Aetobatus cappettai and Taeniurops sp.) for the first time from these beds. These additional findings from Baripada Beds also represent the first report of elasmobranch species, namely: Carcharhinus amblyrhynchoides, C. brevipinna, Physogaleus hemmooriensis and Aetobatus cappettai from the Miocene deposits of the Indian subcontinent. The collected fauna in association with foraminifera and molluscs reported from here suggests the deposition of Baripada Beds in a coastal, lagoonal, near-shore environment under neritic conditions connected to the open ocean. Beta diversity (Sørensen–Dice coefficient) correlation study of the Miocene elasmobranchs of India and their global counterparts shows that the Upper Miocene fauna had a close affinity to that of the South Pacific and the Indo-Pacific oceans, suggesting a shift in migration path after the permanent closure of the east Mediterranean seaway.