Thesis Progress at CES on 11 October 2017 at 3:00 pm titled "Roles of climate and geography in governing ‘into India’ dispersal of freshwater snail family Viviparidae" by Maitreya Sil from CES, IIScHost of the speakerESS
The India-Asia collision in the early Tertiary and the subsequent climatic and geographic shifts had profound effect in shaping the biotic community on both the landmasses. However, the impact of such abiotic factors on freshwater invertebrates is not well understood. Freshwater snail family Viviparidae is known to have colonized India from Southeast Asia, but knowledge on the temporal pattern of these dispersals is lacking. Understanding these patterns will help us elucidate the role of climatic fluctuations and geographic changes in shaping the biogeography of freshwater organisms across the India-Southeast Asia interface. To this end, samples of all the described species of Viviparid snails were collected across the Indian subcontinent and multiple molecular markers were sequenced. Phylogenetic analysis, molecular dating, and ancestral area reconstruction were carried out with a dataset consisting of the Indian species and major Southeast Asian Viviparid genera. Preliminary results suggest independent colonization of the Indian subcontinent by two distinct lineages of viviparid snails. Furthermore, contrary to our expectations, one of the two lineages seems to have dispersed after the late Miocene aridification intensified in Peninsular India. A clearer picture will soon emerge following further analysis. Comparative studies on the ability of the two lineages to withstand aridity might provide insight into this intriguing pattern.