Repeated evolution of terrestrial lineages in a continental lizard radiation

Lajmi, A and Verma, A and Karanth, KP (2020) Repeated evolution of terrestrial lineages in a continental lizard radiation. In: Journal of Evolutionary Biology, 33 (1). pp. 57-66.

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Abstract

The “early-burst” model of adaptive radiation predicts an early increase in phenotypic disparity concurrent with lineage diversification. Although most studies report a lack of this coupled pattern, the underlying processes are not identified. The continental radiation of Hemidactylus geckos from Peninsular India includes morphologically diverse species that occupy various microhabitats. This radiation began diversifying ~36 Mya with an early increase in lineage diversification. Here, we test the “early-burst” hypothesis by investigating the presence of ecomorphs and examining the pattern of morphological diversification in a phylogenetic framework. Two ecomorphs—terrestrial and scansorial species—that vary significantly in body size and toepad size were identified. Unlike the prediction of the “early-burst” model, we find that disparity in toepad morphology accumulated more recently ~14 Mya and fit the Ornstein-Ulhenbeck model. Ancestral state reconstruction of the two ecomorphs demonstrates that terrestrial lineages evolved independently at least five times from scansorial ancestors, with the earliest diversification in terrestrial lineages 19–12 Mya. Our study demonstrates a delayed increase in morphological disparity as a result of the evolution of terrestrial ecomorphs. The diversification of terrestrial lineages is concurrent with the establishment of open habitat and grasslands in Peninsular India, suggesting that the appearance of this novel resource led to the adaptive diversification.

Item Type:	Journal Article
Publication:	Journal of Evolutionary Biology
Publisher:	Blackwell Publishing Ltd
Additional Information:	The copyright for this article belongs to Blackwell Publishing Ltd.
Keywords:	adaptive radiation; body size; ecomorphology; evolution; grassland; lizard; microhabitat; phenotypic plasticity; prediction, India, Gekkonidae; Hemidactylus; Mya; Squamata, adaptation; anatomy and histology; animal; classification; ecosystem; India; lizard; phylogeny; species differentiation, Adaptation, Physiological; Animals; Ecosystem; Genetic Speciation; India; Lizards; Phylogeny
Department/Centre:	Division of Biological Sciences > Centre for Ecological Sciences
Date Deposited:	08 Feb 2023 11:04
Last Modified:	08 Feb 2023 11:04
URI:	https://eprints.iisc.ac.in/id/eprint/80079

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