Systematics And Biogeography Of Scolopendrids Of The Western Ghats, India

Abstract

In this thesis, the biogeography of the centipede family Scolopendridae of the Western Ghats (WG)was studied. First, a novel limited sampling approach to identify putative Gondwanan origin wherein sampling of was confined to one of the Gondwanan fragments, i.e. the WG was developed. The results indicated that at least four genera, Scolopendra, Cormocephalus, Rhysida and Digitipes of Scolopendridae, have diversified on the drifting peninsular Indian plate, and thus might have a Gondwanan origin. Three of these genera, Cormocephalus, Scolopendra and Rhysida, might have dispersed out of India and Digitipes has remained a Gondwanan relict. Second, an integrative frame work was used to delimit species boundaries in the genus Digitipes which was characterized as an ancient, endemic and monophyletic group. A new phylogenetic hypothesis was proposed for the genus Digitipes, with eight sampled species of which three were described and five were potentially new species. Among the five potentially un-described species, three were morphologically cryptic, emphasizing the effectiveness of this approach in revealing cryptic diversity. Third, historical biogeography of wet evergreen species of WG was evaluated using the genus Digitipes from the WG. Biogeographic and divergence date estimation suggest that the southern WG was indeed a refuge for Digitipes species of the WG during Cretaceous volcanism. The dated molecular phylogeny of family Scolopendridae as well as of genus Digitipes obtained in the current study will be useful in future comparative biogeography and diversification studies in the WG.