International Journal of Geosciences, 2022, 13, 609-626 https://www.scirp.org/journal/ijg ISSN Online: 2156-8367 ISSN Print: 2156-8359 DOI: 10.4236/ijg.2022.138033 Aug. 9, 2022 609 International Journal of Geosciences Record of Additional Middle Eocene Vertebrate Remains from the Mikir Hills, NE India: Implications on Paleoenvironment and Paleobiogeography Shantajhara Biswal 1,2 , Kapesa Lokho 1* , Annie Needham 3 , Ansuya Bhandari 4 , Uma Kant Shukla 2 , Kezhakielie Whiso 5 , Kuldeep Prakash 2 1 Wadia Institute of Himalayan Geology, Dehradun, India 2 Department of Geology, Banaras Hindu University, Varanasi, India 3 Department of Geology, School of Basic and Applied Sciences, Sri Guru Ram Rai (P.G) College, Dehradun, India 4 Birbal Sahni Institute of Paleosciences, Lucknow, India 5 Ampeli, Danda Lackhond Shastradhara Road, Dehradun, India Abstract The fossiliferous middle Eocene deposits of Sylhet Limestone of Mikir Hills have yielded vertebrate and invertebrate faunas. The fossil assemblages rec- orded in this contribution consist of shark, ray, crocodile, conical tooth, bro- ken fragments and echinoderm spines. Ray and crocodile tooth are reporting for the first time from the Mikir Hills. Paleoenvironmental analysis based on the fossil fish assemblage in association with invertebrate (foraminifera) re- mains and sedimentogical observations suggest a shallow marine environment ranging from open marine, inner neritic to more proximal coastal settings. Also, the presence of common marine elements (similar faunas) from Kutch, Rajasthan, Himachal Pradesh, Assam (India), New Hampshire, Libya, Iraq, Iran, North Western Sahara (Algeria), Tanzania (East Africa), Italy, Germa- ny, Southern North Sea basin (Europe) based on previous published works and the present finding testifies to the connection of the Tethys Sea during Lutetian-Bartonian of middle Eocene. Keywords Eocene, Fish Teeth, Mikir Hills, Paleoenvironment, Ray, Sylhet Limestone 1. Introduction Mikir Hills in Assam and Shillong Plateau in Meghalaya (Figure 1) are the nor- How to cite this paper: Biswal, S., Lokho, K., Needham, A., Bhandari, A., Shukla, U.K., Whiso, K. and Prakash, K. (2022) Record of Additional Middle Eocene Vertebrate Remains from the Mikir Hills, NE India: Implications on Paleoenvironment and Pa- leobiogeography. International Journal of Geosciences, 13, 609-626. https://doi.org/10.4236/ijg.2022.138033 Received: May 27, 2022 Accepted: August 6, 2022 Published: August 9, 2022 Copyright © 2022 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access