Discovery of a new family of amphibians from northeast India with ancient links to Africa.
Journal: 2012/August - Proceedings. Biological sciences
ISSN: 1471-2954
Abstract:
The limbless, primarily soil-dwelling and tropical caecilian amphibians (Gymnophiona) comprise the least known order of tetrapods. On the basis of unprecedented extensive fieldwork, we report the discovery of a previously overlooked, ancient lineage and radiation of caecilians from threatened habitats in the underexplored states of northeast India. Molecular phylogenetic analyses of mitogenomic and nuclear DNA sequences, and comparative cranial anatomy indicate an unexpected sister-group relationship with the exclusively African family Herpelidae. Relaxed molecular clock analyses indicate that these lineages diverged in the Early Cretaceous, about 140 Ma. The discovery adds a major branch to the amphibian tree of life and sheds light on both the evolution and biogeography of caecilians and the biotic history of northeast India-an area generally interpreted as a gateway between biodiversity hotspots rather than a distinct biogeographic unit with its own ancient endemics. Because of its distinctive morphology, inferred age and phylogenetic relationships, we recognize the newly discovered caecilian radiation as a new family of modern amphibians.
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Proc Biol Sci 279(1737): 2396-2401

Discovery of a new family of amphibians from northeast India with ancient links to Africa

Department of Environmental Studies, Systematics Laboratory, Centre for Environmental Management of Degraded Ecosystems, University of Delhi, Delhi, 110 007, India
Centre of Excellence Programme, Centre for Environmental Management of Degraded Ecosystems, University of Delhi, Delhi, 110 007, India
Department of Zoology, The Natural History Museum, London SW7 5BD, UK
Biology Department, Amphibian Evolution Laboratory, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
Author for correspondence (ni.ca.ud.edmec@ujibds).
Present address: Department of Animal Biology, Biodiversity Research Institute UB (IRBio), University of Barcelona, 08028 Barcelona, Spain.
Received 2012 Jan 22; Accepted 2012 Feb 2.

Abstract

The limbless, primarily soil-dwelling and tropical caecilian amphibians (Gymnophiona) comprise the least known order of tetrapods. On the basis of unprecedented extensive fieldwork, we report the discovery of a previously overlooked, ancient lineage and radiation of caecilians from threatened habitats in the underexplored states of northeast India. Molecular phylogenetic analyses of mitogenomic and nuclear DNA sequences, and comparative cranial anatomy indicate an unexpected sister-group relationship with the exclusively African family Herpelidae. Relaxed molecular clock analyses indicate that these lineages diverged in the Early Cretaceous, about 140 Ma. The discovery adds a major branch to the amphibian tree of life and sheds light on both the evolution and biogeography of caecilians and the biotic history of northeast India—an area generally interpreted as a gateway between biodiversity hotspots rather than a distinct biogeographic unit with its own ancient endemics. Because of its distinctive morphology, inferred age and phylogenetic relationships, we recognize the newly discovered caecilian radiation as a new family of modern amphibians.

Keywords: caecilian amphibians, Chikilidae, new family, systematics, northeast India
Abstract

Acknowledgements

The research was supported by funding from the University of Delhi (support to faculty for strengthening R&D programme); DBT, Government of India; IUCN/ASG/SSC (lost amphibian species of India, 2007); The Percy Sladen Memorial Fund, The Linnaean Society, London to S.D.B; Critical Ecosystem Partnership Fund, Conservation International, USA; The Royal Society and Indian DST (to S.D.B. and D.J.G); Direct Senior Research Fellowship, Council of Scientific & Industrial Research (CSIR), India (9/45 (1082)/2011-EMR-I to R.G.K); European Union Marie Curie Mobility and Training Programme (PIEF-GA-2009-237658 to D.S.M.); Natural Environmental Research Council studentship (NE/F009011/1 to E.S.); European Research Council (Grant 204509, project TAPAS, to F.B.); the Fonds voor Wetenschappelijk Onderzoek Vlaanderen postdoctoral fellowship (FWOTM573 to I.V.B.). Forest departments (Arunachal Pradesh, Assam, Manipur, Meghalaya, Nagaland, Tripura and West Bengal) provided study permits to S.D.B.

Acknowledgements

Endnote

Between 1961 and 2001, the human population in northeast India grew by a whopping 24 million (Census of India, retrieved from http://censusindia.gov.in/), an increase of ca 0.6 million people per year. This excludes the population of three districts of West Bengal viz. Cooch Behar, Jalpaiguri and Darjeeling, which are considered as part of the biogeographic part of northeast India.

Endnote
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