Agamid lizards from the early eocene of western India: oldest cenozoic lizards from south Asia

Abstract

The discovery of agamid lizards from the Lower Eocene (ca. 53 Ma) deposits of Vastan Lignite Mine, western India, is reported, based on a number of dentaries and one maxilla. There are at least two distinct sets of dentary bones with varying morphologies, indicating the presence of two different taxa, Vastanagama susani gen. et sp. nov. and Tinosaurus indicus sp. nov. The new finds represent the oldest known occurrence of agamid lizards in the Cenozoic of South Asia. Though tricuspid, the teeth on the dentaries and maxilla of V. susani gen. et sp. nov. and T. indicus sp. nov. appear more closely related to Tikiguania estesi, a Late Triassic taxon from India, than to the various species of Tinosaurus known from the Paleogene of North America, Europe and Asia. Differences include the development of lateral cuspules on the posterior teeth and the presence of a broad, flat or convex platform-like subdental ridge on the dentaries of V. susani gen. et sp. nov. The significance of these fossils in the context of 'Out-of-India' and 'In-to-India' paleobiogeographic hypotheses is discussed.