Title Phylogeny and biogeography of the endemic Hemidactylus geckos of the Indian subregion suggest multiple dispersals from Peninsular India to Sri Lanka
Publication TypeJournal Article
Year of Publication2019
AuthorsLajmi A, Bansal R, Giri VB, Karanth P
JournalZoological Journal of the Linnean Society

Factors shaping biotic assembly of an island compared with the mainland are of considerable interest in biogeography, and the island of Sri Lanka and mainland India provide an interesting setting in which to study this process. We tested two contrasting hypotheses, faunal exchange vs. in situ diversification, to explain how the biota of Sri Lanka might have assembled. We studied the radiation of Hemidactylus geckos, endemic to India and Sri Lanka, to understand the biogeographical processes underlying the faunal assembly of Sri Lanka. We performed molecular phylogenetic analysis, divergence data estimation and ancestral area reconstruction. Diversification in this radiation began ~34.5 Mya in India, followed by seven independent dispersal events from India to Sri Lanka. Two dispersal events occurred in the Early to Middle Miocene, leading to two endemic Sri Lankan species. Marine transgression events separating the two landmasses are likely to have led to vicariant speciation in these cases. The other five dispersal events led to range expansion in species largely restricted to open semi-arid habitats and were likely to be more recent. These results indicate that the biotic exchange model better explains the assembly of Sri Lankan Hemidactylus geckos.