High diversity of acrodontan lizards in the Early Eocene Vastan Lignite Mine of India
Department of Geology, H.N.B. Garhwal University, Srinagar 246175, Uttarakhand, India. E-mail: rajendra.rana1@gmail.com
Centre de Recherches sur la Paléobiodiversité et les Paléoenvironnements, UMR-CNRS 7207, Département Histoire de la Terre, Muséum National d’Histoire Naturelle, CP 38, rue Buffon 8, 75231 Paris cedex 05, France. E-mail: axuxgxex@aol.com
Scientific Heritage Survey, Royal Belgian Institute of Natural Sciences, rue Vautier 29, B-1000 Brussels, Belgium. E-mail: annelise.folie@naturalsciences.be
Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, U.S.A. E-mail: kdrose@jhmi.edu
Wadia Institute of Himalayan Geology, 33 General Mahadeo Singh Road, Dehradun 248001, Uttarakhand, India. E-mail: kumark@wihg.res.in
Department of Geology, H.N.B. Garhwal University, Srinagar 246175, Uttarakhand, India. E-mail: rajendra.rana1@gmail.com
Centre of Advanced Study in Geology, Lucknow University, Lucknow 226001, India. E-mail: ashok.sahni@gmail.com
O.D. Earth and History of Life, Royal Belgian Institute of Natural Sciences, rue Vautier 29, B-1000 Brussels, Belgium. E-mail: thierry.smith@naturalsciences.be
Abstract
The Ypresian Cambay Formation at Vastan Mine in Gujarat, western India, has yielded a rich herpetological fauna including snakes, lizards and amphibians, but strangely, lizards are only represented by Acrodonta. Here we describe the acrodontan assemblage based on numerous, diverse and well-preserved dentaries, premaxillae, and maxillae. Among the five taxa described one new genus and species characterised by a short splenial represents the youngest occurrence of the extinct family Priscagamidae. The other four taxa belong to the extant family Agamidae. Two of them previously known, Vastanagama susanae and Tinosaurus indicus, are here revised. The two other taxa are new. The first one, Suratagama neeraae gen. and sp. nov., is characterised by the presence of six small pleurodont teeth with a nearly cylindrical shaft and an obtusely pointed apex. The second one, Indiagama gujarata gen. and sp. nov., has rectangular teeth in lateral view, unicuspid crowns forming a nearly horizontal cutting edge, and wear facets on both the lingual and labial sides of the dentary. Our results confirm that Acrodonta is the only lizard group present in Vastan, whereas many other groups are already present from the beginning of the Early Eocene on the other continents. The diversity of the agamids in Vastan and the absence of non-acrodontan lizard in India tentatively support the Out-of-India hypothesis for agamids.