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Phylogeography of spiny mice (genus Acomys, Rodentia: Muridae) from the south-western margin of the Sahara with taxonomic implications

Authors

  • VIOLAINE NICOLAS,

    Corresponding author
    1. Muséum National d'Histoire Naturelle, Département de Systématique et Evolution, UMR 7205, Laboratoire Mammifères et Oiseaux, 57 rue Cuvier, CP 51, 75005 Paris, France
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  • LAURENT GRANJON,

    1. IRD, Centre de Biologie et de Gestion des Populations (UMR IRD/INRA/CIRAD/MontpellierSupAgro), Campus International de Baillarguet, CS 30016, 34988 Montferrier-sur-Lez cedex, France
    2. IRD, UMR 022 CBGP, Campus de Bel-Air, BP 1386, Dakar, CP 18524, Senegal
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  • JEAN-MARC DUPLANTIER,

    1. IRD, Centre de Biologie et de Gestion des Populations (UMR IRD/INRA/CIRAD/MontpellierSupAgro), Campus International de Baillarguet, CS 30016, 34988 Montferrier-sur-Lez cedex, France
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  • CORINNE CRUAUD,

    1. Genoscope. Centre National de Sequençagel, 2 rue Gaston Crémieux, CP5706, 91057 Evry Cedex, France
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  • GAUTHIER DOBIGNY

    1. IRD, Centre de Biologie et de Gestion des Populations (UMR IRD/INRA/CIRAD/MontpellierSupAgro), Campus International de Baillarguet, CS 30016, 34988 Montferrier-sur-Lez cedex, France
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    • Current address: Centre Régional Agrhymet, Rive Droite, BP11011, Niamey, Niger.


E-mail: vnicolas@mnhn.fr

Abstract

The present study aims to depict the overall pattern of Acomys history in south-western Sahara. We tested the specific predictions that: (1) several mitochondrial clades can be identified and that they coincide with the described species; (2) successive phases of desert expansion and contraction during the last 3 Myr have resulted in several phases of demographic expansion and population fragmentation in Acomys; and (3) isolation-by-distance occurs. The extent of phylogeographic patterns and molecular genetic diversity (cytochrome b gene and D-loop) were addressed in a survey of 90 individuals of Acomys from 38 localities. Our phylogeographical analyses show a strong genetic structure within western Saharan Acomys, with several phylogroups displaying non-overlapping geographic distributions. Restricted gene flow with isolation-by-distance was recorded and a signal of population expansion was detected within several clades. We suggest that during arid or semi-arid paleoclimatic periods, when large sandy areas were present, Acomys was restricted to rocky massifs, whereas, in more humid periods, when savannah and/or steppe habitat prevailed, this species was able to disperse and to survive outside rocky areas because food resources were abundant. Based on a comprehensive sampling and the use of an integrative approach (i.e. combining cytogenetic, molecular and morphological data), we firmly propose that Acomys airensis should be considered as a junior synonym of Acomys chudeaui. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 29–46.

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