First documentation of Miocene shark teeth from South Garo Hills District of Meghalaya with a synopsis on the Miocene Chondrichthyes of India and palaeoenvironmental interpretation

Shark teeth from representatives of four families, including Lamnidae, Hemigaleidae, Carcharhinidae and Sphyrnidae belonging to five genera, namely Isurus, Lamna, Hemipristis, Carcharhinus and Sphyrna, were recorded and documented for the first time from the South Garo Hills District of Meghalaya from the Baghmara and Chengapara formations of the Garo Group of rocks of Oligo-Miocene age. They show close affinity and similarities to the Miocene shark tooth assemblages recorded from the Baripada beds of Orissa and the Surma basin of Mizoram. These selachian assemblages from South Garo Hills point to a shallow marine, nearshore coastal environment well connected to the open sea. Thus, the present study provides new insights on the palaeodiversity and palaeoenvironmental setup of the Miocene sediments of South Garo Hills of Meghalaya and also enhances the existing knowledge of chondrichthyan diversity in India during the Miocene time.