Comparative Phylogeography of select scolopendrids from Western Ghats

Abstract

Comparative phylogeography examines the patterns and drivers of genetic variation and population structure in co-distributed species from a geographical and historical perspective. It helps us elucidate how biotic and abiotic factors have historically shaped the community structure and biodiversity across an entire landscape. The Western Ghats is a mountain range that runs parallel to the west coast of India and has also been recognised as a biodiversity hotspot. Biogeographically, it can be divided into three subregions: Southern, Central and Northern Western Ghats. Further, this landscape has three geographical and climatic gaps: the Palghat Gap, Shencottah Gap and Goa Gap and multiple riverine barriers. In this study, I examined the comparative phylogeography of a few selected scolopendrids from the Western Ghats. Specifically, we examined the comparative phylogeography of the Western Ghats endemic species from the genera Ethmostigmus and Rhysida, which differ significantly in their body size, dispersal ability, and species ecology. We meticulously chose co-distributed species from across the Western Ghats with varying degrees of geographical overlap in their distribution. We hypothesised that the phylogeographical concordance would also increase as the degree of geographical overlap increases. We used mtDNA and nuDNA data to reconstruct molecular phylogeny and mtDNA to reconstruct haplotype networks and to assess the population structure. Our results support our expectation of phylogeographic concordance in co-distributed species and highlight that geography dictated the phylogeography of Scolopendrids rather than species-specific traits. Our study identifies geography, climate, and rivers as important dispersal barriers for scolopendrids, driving their genetic variation and population structure.