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Are the native giant tortoises from the Seychelles really extinct? A genetic perspective based on mtDNA and microsatellite data

Authors

  • Eric P. Palkovacs,

    Corresponding author
    1. Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street,
      Eric P. Palkovacs. Fax: + 1203 4327394; E-mail: eric.palkovacs@yale.edu
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  • Monique Marschner,

    1. Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street,
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  • Claudio Ciofi,

    1. Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street,
    2. Molecular Systematics and Conservation Genetics Laboratory, Yale Institute for Biospheric Studies, 21 Sachem Street, New Haven, CT 06520, USA,
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  • Justin Gerlach,

    1. University Museum of Zoology Cambridge, Department of Zoology, Downing Street, Cambridge, CB2 EJ3, UK
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  • Adalgisa Caccone

    1. Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street,
    2. Molecular Systematics and Conservation Genetics Laboratory, Yale Institute for Biospheric Studies, 21 Sachem Street, New Haven, CT 06520, USA,
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Eric P. Palkovacs. Fax: + 1203 4327394; E-mail: eric.palkovacs@yale.edu

Abstract

The extinction of the giant tortoises of the Seychelles Archipelago has long been suspected but is not beyond doubt. A recent morphological study of the giant tortoises of the western Indian Ocean concluded that specimens of two native Seychelles species survive in captivity today alongside giant tortoises of Aldabra, which are numerous in zoos as well as in the wild. This claim has been controversial because some of the morphological characters used to identify these species, several measures of carapace morphology, are reputed to be quite sensitive to captive conditions. Nonetheless, the potential survival of giant tortoise species previously thought extinct presents an exciting scenario for conservation. We used mitochondrial DNA sequences and nuclear microsatellites to examine the validity of the rediscovered species of Seychelles giant tortoises. Our results indicate that the morphotypes suspected to represent Seychelles species do not show levels of variation and genetic structuring consistent with long periods of reproductive isolation. We found no variation in the mitochondrial control region among 55 individuals examined and no genetic structuring in eight microsatellite loci, pointing to the survival of just a single lineage of Indian Ocean tortoises.

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