Worldwide mitochondrial DNA diversity and phylogeography of pilot whales (Globicephala spp.)

Authors

  • MARC OREMUS,

    Corresponding author
    1. School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
      E-mail: m.oremus@auckland.ac.nz
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  • ROSEMARY GALES,

    1. Resource Management and Conservation Division, DPIW, GPO Box 44, Hobart, Tasmania 7001, Australia
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  • MEREL L. DALEBOUT,

    1. School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
    2. School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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  • NAOKO FUNAHASHI,

    1. Japan representative, International Fund for Animal Welfare, 1-2-10 Koyama, Higashi Kurume-shi, Tokyo 203-0051, Japan
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  • TETSUYA ENDO,

    1. Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, 1757 Ishikari-Tobetsu, Hokkaido 061-0293, Japan
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  • TAKAHIRO KAGE,

    1. Mie University, 1577 Kurimamachiya-cho, Tsu City, Mie Prefecture, Japan 514-8507
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  • DEBBIE STEEL,

    1. School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
    2. Marine Mammal Institute and Department of Fisheries and Wildlife, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Oregon State University, Newport, OR 97365, USA
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  • SCOTT C. BAKER

    1. School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
    2. Marine Mammal Institute and Department of Fisheries and Wildlife, Hatfield Marine Science Center, 2030 SE Marine Science Drive, Oregon State University, Newport, OR 97365, USA
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E-mail: m.oremus@auckland.ac.nz

Abstract

Pilot whales (Globicephala spp.) provide an interesting example of recently diverged oceanic species with a complex evolutionary history. The two species have wide but largely non-overlapping ranges. Globicephala melas (long-finned pilot whale; LFPW) has an antitropical distribution and is found in the cold-temperate waters of the North Atlantic and Southern Hemisphere, whereas Globicephala macrorhynchus (short-finned pilot whale; SFPW) has a circumglobal distribution and is found mainly in the tropics and subtropics. To investigate pilot whale evolution and biogeography, we analysed worldwide population structure using mitochondrial DNA (mtDNA) control region sequences (up to 620 bp) from a variety of sources (LFPW = 643; SFPW = 150), including strandings in New Zealand and Tasmania, and whale-meat products purchased on the markets of Japan and Korea. Phylogenetic reconstructions failed to support a reciprocal monophyly of the two species, despite six diagnostic substitutions, possibly because of incomplete lineage sorting or inadequate phylogenetic information. Both species had low haplotype and nucleotide diversity compared to other abundant widespread cetaceans (LFPW, π = 0.35%; SFPW, π = 0.87%) but showed strong mtDNA differentiation between oceanic basins. Strong levels of structuring were also found at the regional level. In LFPW, phylogeographic patterns were suggestive either of a recent demographic expansion or selective sweep acting on the mtDNA. For SFPW, the waters around Japan appear to represent a centre of diversity, with two genetically-distinct forms, as well as a third population of unknown origin. The presence of multiple unique haplotypes among SFPW from South Japan, together with previously documented morphological and ecological differences, suggests that the southern form represents a distinct subspecies and/or evolutionary significant unit. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 729–744.

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