A mega-toothed shark, Otodus megalodon (Agassiz, 1835) from the Middle Miocene Bhuban Formation of Mizoram, India

Abstract

The Bhuban Formation of Mizoram is known for its fossil assemblages of invertebrates, foraminiferans, sharks and batoids. Recent fieldwork at Tuithum Quarry of the Bhuban Formation, Mizoram, yielded an isolated tooth of Otodus megalodon (Agassiz, 1835), the largest fish that ever lived on earth. The present record of O. megalodon is not only the first-time report from the Miocene of Mizoram but also from the entire Northeast India. The O. megalodon was a cosmopolitan giant predator, known to inhabit tropical, subtropical, and temperate seas during the early Miocene to early Pliocene epochs. Based on regression analyses, the tooth belonging to this individual specimen is estimated to indicate a total body length of approximately 7.81 meters, suggesting that it was likely a juvenile. The present finding of O. megalodon and the earlier record of the elasmobranch fauna and associated invertebrates indicate that a warm, shallow marine (nearshore), high-energy environment prevailed during the deposition of the upper Bhuban Formation.