Molecular systematics of caeciliid caecilians (Amphibia: Gymnophiona) of the Western Ghats, India

Gower, David J.; Mauro, Diego San; Giri, Varad B.; Bhatta, Gopalakrishna; Govindappa, Venu; Kotharambath, Ramachandran; Oommen, Oommen V.; Fatih, Farrah A.; Mackenzie‐Dodds, Jacqueline; Nussbaum, Ronald A.; Biju, S. D.; Shouche, Yogesh S.; Wilkinson, Mark

doi:10.1016/j.ympev.2011.03.002

Cited by 25 publications

(26 citation statements)

References 47 publications

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“…We did not use all of the samples analysed by Gower et al . () but to increase computational efficiency we instead selected one specimen from each major lineage. Our sampling included all nominal species of Indian indotyphlid except G. tejaswini Kotharambath, Wilkinson, Oommen & Gower, 2015, for which only 12s and 16S rRNA sequences are available (this species is more closely related to G. carnosus than any other nominal species: Gower et al ., ).…”

Section: Methodsmentioning

confidence: 99%

“…Gower et al . () presented a molecular phylogeny (without estimated divergence dates) for Indian indotyphlids, but their sampling lacked G. orientalis as well as another recently described species of Gegeneophis, G. pareshi Giri, Gower, Gaikwad & Wilkinson, 2011. Here, we present results of phylogenetic analyses including these two species.…”

Section: Introductionmentioning

confidence: 99%

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The role of wet‐zone fragmentation in shaping biodiversity patterns in peninsular India: insights from the caecilian amphibianGegeneophis

Gower

Agarwal

Karanth

et al. 2016

Journal of Biogeography

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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. ResultsThe 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 GhatsGegeneophis 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.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The role of wet‐zone fragmentation in shaping biodiversity patterns in peninsular India: insights from the caecilian amphibianGegeneophis

Gower

Agarwal

Karanth

et al. 2016

Journal of Biogeography

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“…1) is a topological synthesis (i.e. one without estimated branch lengths) constructed from well-supported relationships in the most recent relevant phylogenetic studies (Wilkinson and Nussbaum 1999;Gower unpublished;Loader 2005;Gower et al 2011;Loader et al 2011;San Mauro et al 2014;Wilkinson et al 2014) and some specific assumptions of monophyly. Assumptions of monophyly, based primarily on caecilian taxonomy, are required because a substantial proportion of the included taxa have never been included in any explicit phylogenetic analyses.…”

Section: Study Samples and Phylogenymentioning

confidence: 99%

Evolution of Cranial Shape in Caecilians (Amphibia: Gymnophiona)

et al. 2014

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Insights into morphological diversification can be obtained from the ways the species of a clade occupy morphospace. Projecting a phylogeny into morphospace provides estimates of evolutionary trajectories as lineages diversified information that can be used to infer the dynamics of evolutionary processes that produced patterns of morphospace occupation. We present here a large-scale investigation into evolution of morphological variation in the skull of caecilian amphibians, a major clade of vertebrates. Because caecilians are limbless, predominantly fossorial animals, diversification of their skull has occurred within a framework imposed by the functional demands of head-first burrowing. We examined cranial shape in 141 species, over half of known species, using X-ray computed tomography and geometric morphometrics. Mapping an existing phylogeny into the cranial morphospace to estimate the history of morphological change (phylomorphospace), we find a striking pattern: most species occupy distinct clusters in cranial morphospace that closely correspond to the main caecilian clades, and each cluster is separated by unoccupied morphospace. The empty spaces in shape space are unlikely to be caused entirely by extinction or incomplete sampling. The main caecilian clades have different amounts of morphological disparity, but neither clade age nor number of species account for this variation. Cranial shape variation is clearly linked to phyletic divergence, but there is also homoplasy, which is attributed to extrinsic factors associated with head-first digging: features of caecilian crania that have been previously argued to correlate with differential microhabitat use and burrowing ability, such as subterminal and terminal mouths, degree of temporal fenestration (stegokrotaphy/ zygokrotaphy), and eyes covered by bone, have evolved and many combinations occur in modern species. We find evidence of morphological convergence in cranial shape, among species that have eyes covered by bone, resulting in a narrow bullet-shaped head. These results reveal a complex history, including early expansion of morphospace and both divergent and convergent evolution resulting in the diversity we observe today.

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“…Although clearly monophyletic (Nussbaum and Ducey 1988;Hedges et al 1993;Gower et al 2011), analyses of (mostly mtDNA) sequence data have been unable to robustly resolve all relationships among the radiation (Hedges et al 1993;Wilkinson et al 2002Wilkinson et al , 2003Loader et al 2007;Gower et al , 2011. ANL could provide a useful tool for Seychelles caecilian systematics and conservation genetics, especially given the increased levels of threat faced, in general, by island biotas (e.g., Frankham 2008).…”

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confidence: 99%

Development of anonymous nuclear markers from Illumina paired-end data for Seychelles caecilian amphibians (Gymnophiona: Indotyphlidae)

Lewis

Maddock

Day

et al. 2014

Conservation Genet Resour

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Anonymous nuclear markers were developed for Seychelles caecilian amphibians. Using a previously published bioinformatics pipeline (developed for Roche 454 data), 36 candidate anonymous nuclear loci (ANL) of at least 180 bp length were identified from Illumina MiSeq next generation sequencing data for five Seychelles species. We designed primer pairs for the 36 candidate ANL and tested these by PCR and Sanger sequencing. Seven ANL amplified and sequenced well for at least five of the six nominal Seychelles caecilian species (in three genera), and represent potentially useful markers for systematics and conservation.

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Molecular systematics of caeciliid caecilians (Amphibia: Gymnophiona) of the Western Ghats, India

Cited by 25 publications

References 47 publications

The role of wet‐zone fragmentation in shaping biodiversity patterns in peninsular India: insights from the caecilian amphibianGegeneophis

The role of wet‐zone fragmentation in shaping biodiversity patterns in peninsular India: insights from the caecilian amphibianGegeneophis

Evolution of Cranial Shape in Caecilians (Amphibia: Gymnophiona)

Development of anonymous nuclear markers from Illumina paired-end data for Seychelles caecilian amphibians (Gymnophiona: Indotyphlidae)

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