Browsing by Author "Nair, Abhilash"

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  • Nair, Abhilash (Helsingin yliopisto, 2012)
    The Western Ghats-Sri Lanka biodiversity hotspot is one of the World s 34 recognized biodiversity hotspots. The current knowledge about amphibian fauna of the Western Ghats is limited, but this region is known to exhibit a high degree of diversity and endemism. Although many species of amphibians are yet to be described from India, about 40% of known amphibian species from this region are threatened by extinction. The Indirana frogs belong to an endemic family, Ranixalidae, and are comprised of ten known species. Studies of this Western Ghats amphibian group are rare, hence the evolutionary relationships, taxonomy and species-level diversity of Indirana frogs have remained unresolved. Furthermore, nothing is known about the extent of genetic variability and differentiation among local populations of a given species. Hence, there is a high degree of uncertainty about the taxonomic status (cf. cryptic species) and potential genetic problems that the Indirana populations are likely to be facing. This study focused on phylogenetic relationships and population genetics of Indirana frogs. Phylogenetic analyses clarified the evolutionary relationships among extant taxa and identified five new cryptic candidate species within the genus. For one of the taxa, Indirana beddomii, detailed population genetic analyses based on novel microsatellite markers represent the first phylogeographic analysis of amphibian differentiation in the Western Ghats. Apart from developing a large number of novel microsatellite loci for I. beddomii, cross-species amplification tests performed with eight other taxa should provide useful genetic tools for studies of other species in this genus. Finally, the first infectious disease (cf. Chytrid and Ranavirus infections) screening of Indian amphibians was performed using samples collected from the Western Ghats. In general, the results of the studies included in this thesis should provide useful information, guidelines and resources for amphibian conservation and biodiversity research in the Western Ghats.