Open access e-Journal Earth Science India eISSN: 0974 – 8350 V. 12 (I), January, 2019, pp. 71-82 http://www.earthscienceindia.info/ 71 Microstructures of Shark Teeth from Late Miocene Deposits of Baripada Beds, Orissa, India N. Amardas Singh 1 , K. Milankumar Sharma 1* , Bikash Jyoti Gogoi 1 , Y. Priyananda Singh 1 and Ningthoujam Premjit Singh 2 1 Department of Geography and Geology, Central University of Punjab, Bathinda-151001 2 Centre for Advanced Studies in Geology, Panjab University Chandigarh-160014 *Email: milankumar.sharma@gmail.com ABSTRACT Numerous shark teeth were collected during the recent geological field work (2017-2018) conducted at the well known shark bearing deposits of Makurmatia section of Late Miocene Baripada Beds, Orissa. Scanning Electron Microscope (SEM) analysis of some of the selected shark teeth ( Galeorhinus sp., Carcharhinus sp., Carcharodon sp.) were carried out to study the microcrostructural arrangement of the teeth enamel. The scanning electron micrographs of the shark teeth enamel crystals are highly ordered and arranged in different fashions as single crystallite enameloid (SCE), bundle crystallite enameloid (BCE) which can be subdivided into parallel bundle enameloid (PBE) and tangled bundle enameloid (TBE) as compared to the basal neoselachian which present only the single crystallite enameloid (SCE). The TBE of the Carcharodon sp. is more matured and more compacted than the other two Carcharhinus sp. and Galeorhinus sp. The microstructural arrangement of Galeorhinus sp, Carcharhinus sp. and Carcharodon sp. suggest that these sharks belong to the modern Neoselachian group of sharks. Keywords: Microstructure, Enamel, Dentine, shark teeth, Miocene, Baripada Beds. INTRODUCTION The studies of a microstructures of the teeth enamels of vertebrate fauna are significantly useful for the reconstruction of phylogeny, evolution of the teeth and enamel, their compositions, mechanical properties, and identification of diets of the animals (Gillis and Donoghue, 2007; Enax et al., 2012; Mao et al., 2015). In case of selachian teeth, microstructural analysis of the crystallite enameloid structures are being used for the determination of the homology and the phylogeny of the Chondrichthyan teeth (Gillis and Donoghue, 2007) and differentiation of Hybodont (primitive) shark teeth and the neoselachian (modern) teeth (Enault et al., 2015). The teeth enamels of the modern neoselachians have different complex structures such as single crystallite enameloid (SCE), bundle crystallite enameloid (BCE) which can be subdivided into parallel bundle enameloid (PBE), tangled bundle enameloid (TBE) and radial bundle enameloid (RBE) as compared to the basal neoselachian which present only the single crystallite enameloid (SCE) (Gillis and Donoghue 2007; Andreev and Cunny 2012, etc.). Please cite this article as: Singh, N. Amardas, Sharma, K. Milankumar, Gogoi, Bikash Jyoti, Singh, Y. Priyananda and Singh, Ningthoujam Premjit (2019) Microstructures of shark teeth from Late Miocene deposits of Baripada Beds, Orissa, India. e-Journal Earth Science India, v. 12, pp. 71-82 https://doi.org/10.31870/ESI.12.1.2019.05