Eocene-Oligocene cooling and the diversification of Hemidactylus geckos in Peninsular India

Lajmi, Aparna and Karanth, Praveen K (2020) Eocene-Oligocene cooling and the diversification of Hemidactylus geckos in Peninsular India. In: MOLECULAR PHYLOGENETICS AND EVOLUTION, 142 .

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Abstract

The Eocene-Oligocene cooling marks a global shift towards a cooler and drier climate, concurrent with significant turnover in biota globally. In Peninsular India, palynological investigations suggest a shift from wet rainforest vegetation to dry and seasonal species during this period. However, the grassland and open habitats that dominate this region at present expanded relatively recently due to Late Miocene intensification of monsoon seasonality. We test the possible role of these climatic shifts in generating the dry habitat diversity of an endemic radiation of Hemidactylus geckos distributed in both wet and dry habitats, by investigating whether (a) the beginning of the diversification of dry habitat lineages overlap with the Eocene-Oligocene cooling or late Miocene aridification and (b) accompanied by an increase in diversification. Molecular data (two nuclear and two mitochondrial gene fragments) were generated for samples collected across Peninsular India, and along with previously published data, a time-calibrated phylogeny was reconstructed. Ancestral state reconstruction of dry and wet habitat states was carried out on the time-calibrated phylogeny and gamma-statistics along with a test for diversity-dependent diversification utilized to examine the trend in lineage accumulation. Results show the ancestral node of this radiation to have a dry habitat state, which began diversifying between 39 and 32 million years ago, concurrent with the Eocene-Oligocene cooling. Furthermore, lineage diversification fit a diversity-dependent model of diversification and the gamma-statistics revealed an early increase in diversification followed by a slow-down later. The deep divergences of dry habitat lineages concurrent with the Eocene-Oligocene cooling suggest that this could have served as an ecological opportunity facilitating an early increase in lineage diversification of Hemidactylus in this region. These results suggest an ancient origin and long persistence of arid ecosystems in Peninsular India.

Item Type:	Journal Article
Publication:	MOLECULAR PHYLOGENETICS AND EVOLUTION
Publisher:	ACADEMIC PRESS INC ELSEVIER SCIENCE
Additional Information:	Copyright of this article belongs to ACADEMIC PRESS INC ELSEVIER SCIENCE
Keywords:	Paleoclimate; Biogeography; Radiation; Aridification; South Asia; Gecko
Department/Centre:	Division of Biological Sciences > Centre for Ecological Sciences
Date Deposited:	20 Jan 2020 09:54
Last Modified:	20 Jan 2020 09:54
URI:	http://eprints.iisc.ac.in/id/eprint/64083

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