Understanding the origins and diversification of Indian blindsnakes

Abstract

Much of systematics done in the past was based on morphological data. One of the drawbacks of using morphological data is that in groups with conserved morphology, the diversity is often underestimated and relationships difficult to infer. One such group are the fossorial blindsnakes (superfamily Typhlopoidea, infraorder Scolecophidia). The diversity, life histories and ecology of such groups remain unexplored due to their sub-terranean and secretive habit. India has around 17 species, spanning four genera and two families. However, many of these species have not been discovered since their first descriptions, and many are suspected to be synonyms. For my PhD, I studied the diversity of the four typhlopoid genera in India, from a phylogenetic and biogeographical perspective, and attempted to understand diversification patterns within one species group, which gave rise to the Indotyphlops braminus, a blindsnake with a surprisingly cosmopolitan distribution. In the first chapter, I explore the phylogenetic positions of the four genera- Gerrhopilus, Indotyphlops, Grypotyphlops and Argyrophis, in the global phylogeny. I use a concatenated dataset of five nuclear markers to reconstruct the phylogenies using maximum likelihood and Bayesian methods. The results show that Indian typhlopoids have very diverse affiliations. Gerrhopilus is retrieved as sister to all other typhlopoids. Grypotyphlops is nested with the African genera, which corroborates its classification based on morphology. Indotyphlops was shown to be polyphyletic, with Indotyphlops porrectus being sister to all southeast Asian typhlopoids, and thus requiring a taxonomic revision. We also find an Indian radiation of Indotyphlops. Argyrophis from India is sister to the Argyrophis from southeast Asia. The second chapter looks at the biogeographic origins of the four genera. The divergence times were estimated using the concatenated five gene dataset used in the first chapter, with nine fossils used to calibrate the time-tree...