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Taxonomic changes DNA might show

Discussion in 'Wildlife & Nature Conservation' started by Zygodactyl, 30 Nov 2016.

  1. Zygodactyl

    Zygodactyl Well-Known Member

    Joined:
    3 Jun 2016
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    Austin, TX
    I know we already have a thread for taxonomy, but since that's all real findings I don't want to spoil it with speculation. The great thing about DNA is that it can answer-longstanding questions, and even show us things we didn't suspect (like falcons and hawks not forming a clade, or tinamous beingnestled within the rattites and puffins within the auks). The less-great thing about DNA is that it's not some magic bullet, and certain methods will sometimes get things wrong (DNA-DNA hybridization for example gave us a lot of new groups we still use today, but also made some connections which other methods have discredited).

    I've recently been thinking about how there are at least two groups with fairly limited DNA-based phylogenetic analysis, where I suspect that the taxonomy is still wrong, so I thought I'd bring my suspicions up here, and ask if anyone else has groups whose internal taxonomy they question.

    The first of these groups are the turacos. Currently, I can only find two papers doing DNA-based phylogenetic analysis within the turacos. One (from 1986) assumed the "gray turacos" as a monophyletic group and only used one species from that group; the focus was on the relationships between green and purple turacos. The other (from 2000) only looked at a single protein.

    I will buy that the green and purple turacos form a clade, and that the purple turacos are not the most basal branch of the clade because that question was the focus of both papers. However I'm still skeptical that the "gray turacos" are monophyletic. The go-away birds look and act more like the green turacos than the plantain eaters. Though it's certainly possible that plaintain-eaters are merely a highly-specialized group of gray turacos, it also wouldn't surprise me if further DNA testing shows that that the go-away birds form a clade with the green and violet turacos, and that the plantain-eaters are actually the most basal turacos.

    Another group I've been thinking about is the sandgrouse. It seems odd to me that the fundamental split of the taxon is in central Asia (both species of one genus and several species of the other are found there). The closest relatives of the sandgrouse are the Madagascar-endemic mesites, the greatest diversity of sandgrouse (in terms of species and forms) is in Africa, and Pterocles is a very diverse genus which includes at two species which rather strongly resemble Syrrhaptes in their plumage and both are found in West Asia.

    Now even together all of these things don't mean that the traditional classification is wrong, in fact all of these facts are consistent with a conservative basal genus in Central Asia and an adaptive radiation of species in the new habitats of Africa. However I cannot find any DNA phylogenetic papers which compare more than one species from each sandgrouse genus. I suspect that a wider range of species were investigated, that at the very least, the spotted and crowned sandgrouse would prove to be more closely related to the Syrrhaptes species than to at least some of the African species.

    As for you all, are there any taxonomic classification you all are skeptical of, and which have limited DNA-based phylogenetic analysis?
     
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