The role of wet-zone fragmentation in shaping biodiversity patterns in peninsular India: insights from the caecilian amphibian Gegeneophis

Gower, David J and Agarwal, Ishan and Karanth, Praveen K and Datta-Roy, Aniruddha and Giri, Varad B and Wilkinson, Mark and San Mauro, Diego (2016) The role of wet-zone fragmentation in shaping biodiversity patterns in peninsular India: insights from the caecilian amphibian Gegeneophis. In: JOURNAL OF BIOGEOGRAPHY, 43 (6). pp. 1091-1102.

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Abstract

Aim Indian biodiversity is concentrated in the wet zone, which is disjunctly distributed in the north-east and in the peninsular Western and Eastern Ghats. The Eastern Ghats region is smaller and less well explored biologically and the affinities and origins of its biota poorly understood. Our aim was to assess whether divergence between east and west lineages might have been caused by fragmentation of the wet zone during Pleistocene climatic fluctuations, by Late Miocene wet-zone contraction or by more ancient events. We present the first dated phylogenetic test of these alternatives by inferring relationships and dating divergences within a wet-zone-restricted lineage endemic to the Eastern and Western Ghats. Location The Eastern and Western Ghats regions of peninsular India. Methods Molecular genetic data (one nuclear and four mitochondrial genes) were newly generated for the only known Eastern Ghats teresomatan caecilian amphibian (Gegeneophis orientalis) and the only Western Ghats congener (G. pareshi) for which molecular data were not previously available. Phylogenetic relationships were inferred for Indian indotyphlids using maximum likelihood and Bayesian inference methods. Divergence times within the inferred phylogeny were estimated using a Bayesian relaxed clock method, with the Seychelles versus Indian indotyphlid divergence calibrated based on the geological separation of their respective continental land masses. Results The single Eastern Ghats species of Gegeneophis is sister to all other (Western Ghats) Gegeneophis. The basalmost (and east-west) split within Gegeneophis likely occurred >35 Ma. Main conclusions Divergence between Eastern and Western Ghats Gegeneophis is too ancient to have been caused by wet-zone contraction in the Miocene or by Pleistocene climatic fluctuations. Our results are consistent with a relatively ancient origin of wet-zone lineages in the Eastern Ghats and a lack of gene flow between Eastern and Western Ghats Gegeneophis for tens of millions of years.

Item Type:	Journal Article
Publication:	JOURNAL OF BIOGEOGRAPHY
Publisher:	WILEY-BLACKWELL
Additional Information:	Copy right for this article belongs to the WILEY-BLACKWELL, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA
Keywords:	biogeography; caecilian; Gegeneophis orientalis; Miocene; molecular dating; phylogeny; Pleistocene; rain forest; Seychelles; wet zone
Department/Centre:	Division of Biological Sciences > Centre for Ecological Sciences
Date Deposited:	19 Aug 2016 10:13
Last Modified:	19 Aug 2016 10:13
URI:	http://eprints.iisc.ac.in/id/eprint/54330

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