Monophyly FAIL

20 May 2009

Slide1Unless you have been living under a slab of oil shale, you will have already heard, read and seen quite a lot about the Eocene primate Darwinius masillae recently described in the online open-access journal PLOSone.  The blogosphere has been, ahem, a-twitter over the “hype” surrounding this important fossil–to the extent that some have even begun to decry the anti-hype hype–and it has provided fodder for some excellent satire.  Even the Old Gray Lady has weighed in.

In my forthcoming (‘cough) book on the late 20th/early 21st C. social history of fossils (tentatively entitled Paleontology After Modernism) I discuss the role of flash-powered websites in the promotion of important fossil discoveries (see: Tiktaalik‘s or Puijila‘s).  Given that Darwinius already has its own book and not one, but two television specials, one of which is narrated by Sir David Attenborough, it comes as no surprise that it has its own flashy website too.

Unfortunately, it appears that the website creators did not bother to read the freely available publication they are trying to summarize, and instead chose to present a woefully outdated picture of primate evolution.  I’m sure Brian Switek will take them to tasks for trotting out the old “march of progress” canard,  and perhaps we can forgive the pervasive “Homo sapians” typo.

Picture 5

However, suggesting that primates “diversified into two key groups: the anthropoids and the prosimians” (see image at top of post) is misleading at best and, at worst, directly contradicts the argument laid out in the new paper.  “Prosimian” is term used to refer to various primates perceived to be um, primitive in their anatomy including lemurs, lorises and tarsiers.  However it has been well known for quite some time that this is not a natural group that can be split from the “anthropoid” monkeys and apes, but rather a paraphyletic group of animals including the direct ancestors of anthropoids, as well as animals only distantly related to anthropoids.

Exactly which “prosimians” are more closely related to anthropoids is a matter of debate, and one that this fossil may shed new light on, though, see Brian’s detailed critique of  the new paper.  It is certainly understandable that the LINK website designers would not want to go into the finer details of this debate, however there is no excuse for falling back on a “simplified” but outdated and erroneous picture of primate evolution.

I’m wholeheartedly in favor of trying to get the public excited about important scientific discoveries, even when it involves some minor exaggeration, disseminating misinformation on the other hand is simply inexcusable.

And don’t get me started on this….

Picture 2

6 Responses to “Monophyly FAIL”

  1. jessica Says:

    You’ve got Primate Fever!

  2. Zach Miller Says:

    Well, to be fair, the paper itself only includes three taxa in its “phylogeny:” Darwinius, Sterpsirrhini, and Haplorhini. The paper strongly implies that Haplorhini is more or less synonymous with the old “prosimian” term, and that Haplorhini is synonymous with “anthropoids.”

    Yeah, it’s a terrible, TERRIBLE phylogeny that was not put through any kind of cladistic analysis. I could come up with the same goddamn tree using humans, water buffalo, and turtles (sort of). Except the placement of Darwinius among its primate peers is less resolved than the placement of water buffalo between lizards and humans.

    The fossil is awesome, the paper is mostly good, but the authors make grant, sweeping taxonomic assumptions without rigorously testing anything. It doesn’t help that their anthropoid synapomorphies (lack of grooming claw and lack of tooth comb) are plesiomorphies for Primates.

  3. [...] Evolving Thoughts, The Knowledge Emporium, Greg Laden, Observations of a Nerd, NGM Blog Central, microecos, A Primate of Modern Aspect and [...]

  4. neil Says:

    Thanks for the comment Zach. My understanding of the original meaning of “prosimian” was essentially all extant primates that are not anthropoids, thus including both strepsirrhines (lemurs, lorises, galago, aye-aye etc.) and haplorrhines (tarsiers). If anthropoids are ultimately found to be closer to strepsirrhines then haplorrhines, “haplorrhine” would become essentially redundant with tarsiiformes.

    I intentionally avoided discussing the paper itself in this post, as so much has already been said obviously there is little light to be shed on the matter by me. While presenting a three taxon phylogeny is obviously a little janky, I actually think the authors are quite careful–in the paper at least–to couch their phylogenetic hypothesis in appropriately cautious language given the lack of a phylogenetic analysis. They intentionally AVOID making sweeping statements. The public statements by some authors have been very different obviously. And the website is simply atrocious.

  5. Zach Miller Says:

    Oh, things make more sense now. Didn’t realize that “haplorrhines” was being used for tarsiers. I haven’t read much on primates since college, when tarsiers were considered freaky little prosimians who were close BUT NOT QUITE anthropoids. Outdated terminology, I’m sure. :-(

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