13 November 2015

Common dolphins reshuffled

A new paper analyzed the systematics of Delphinus and found that D. capensis is not a valid species. Apparently, there are still two species: the long-billed D. bairdii, pretty much endemic to California, and the very widespread and variable D. delphis, with at least three subspecies (including dwarf D. d. ponticus in the Black Sea and very long-beaked D. d. tropicalis in the Indian Ocean).

http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0140251

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6 Comments

  • 14 November 2015
    mikehoit

    To clarify – is the D. tropicalis of this study the same form as that named D. capensis in (e.g.) Shirihai et al?

  • 15 November 2015
    morganchurchill

    Not terribly surprising, but part of me is disappointed that there was no nuclear data included, some of which was previously sampled. Phylogenies based on a single gene can be inaccurate, as acknowledged by the authors themselves, and Amaral DID sample some nuclear DNA in her study, so at least some sequences were available.

    The morphology was almost an afterthought of this study. They could have at least done some basic statistics on the data, which would have probably supported their conclusions. As someone who is into cranial morphometrics, its a bit disappointing to see it’s application completely ignored.

    • 16 November 2015
      vdinets

      I agree, with nuclear data these conclusions might still be overtuned. I find it a bit suspicious that in some places two morphotypes occur together.

      • 16 November 2015
        morganchurchill

        that is my concern as well. Rigorous morphometric analysis would be key here. After all it’s possible that the two “morphs” actually show greater variation, and the very little morphologic data they showed in the paper may suggest intermediate forms, which basically just means that the morphs are extreme endpoints in variation and not significantly different.

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