Mystery of the missing Malawisaurus vertebra

April 5, 2009

Quick story: in 1993, Jacobs et al. described the basal titanosaur Malawisaurus based on reasonably complete material from, you guessed it, Malawi. This was kind of a big deal, in that Malawisaurus was at the time the most complete sauropod from the Cretaceous of Africa, and also provided important information on titanosaur skulls. Elizabeth Gomani monographed the beast in her dissertation, and the full description was published in Palaeontologica Electronica in 2005. Both relevant papers are freely available, at least as of this writing, just click on the links above or in the refs section at the end of the post.

I first saw the Malawisaurus material back in  1998 and even CT scanned some it, thanks to the generosity of Elizabeth, Lou Jacobs, and Dale Winkler. Kent Sanders and I always planned to write up the results of the CT scans with Elizabeth, but she has gone back to Malawi and according to rumor gotten involved in the government. In any case, she is out of touch. Which leaves me in the odd position of having some pretty data collected in collaboration with someone who has left the field and is currently unreachable. I’m not ready to do a full-on description of the CT results without some kind of blessing from Elizabeth, but I have decided to stop completely suppressing the info when it might do some good. Hence the pictures of the pneumatic caudal in the new paper (Wedel 2009:fig. 2).

ANYWAY–as always I intended this post to be the soul of brevity but find myself writing a small paper–something has always bothered me about Malawisaurus and I’ve never gotten around to either pointing it out or asking those presumably in the know (i.e., Elizabeth and Lou). Here’s the deal: in the first paper, Jacobs et al. (1993:text-fig. 1) figured “No. 89-78; cervical vertebra, right lateral view” (sorry for the too-small image, it’s all I could get out of the PDF):

malawisaurus-1993

This vert is not figured in any of the more recent papers on Malawisaurus, including Gomani (2005). Also, it doesn’t look anything like the cervicals figured by Gomani (2005:fig. 9):

malawisaurus-cervicals-480

Here are some reasons why No. 89-78 can’t be Malawisaurus:

  • The shapes of the neural spines vary a lot down the column in Malawisaurus, but at no point do any of them look like the tall, squared-off blade of No. 89-78. In fact, I’ve never seen this neural spine shape in any sauropod.
  • The parapophyses of Malawisaurus are long, thin plates, much like those of Sauroposeidon. This is in sharp contrast to the huge and nearly circular parapophyseal stump on No. 89-78.
  • Like many titanosaurs, Malawisaurus does not have big pneumatic foramina (or “pleurocoels”) on the lateral sides of the cervical centra. Instead, the centra are deeply waisted and have lots of little pneumatic foramina, again as in Sauroposeidon (hmm…I’d never given much thought to all the similarities there…). No. 89-78 doesn’t seem to have anything at all on the lateral sides of the centra, at least as drawn, which is not only in stark contrast to Malawisaurus but also to every eusauropod out there.
  • The centra of the Malawisaurus cervicals are proportionally very long and dorsoventrally waisted (meaning that the bottom of the centrum is arched in lateral view). The centrum of No. 89-78 is a straight, comparatively tubby cylinder.

So if No. 89-78 ain’t Malawisaurus, what is it? Gomani (2005) also described the new taxon Karongasaurus based on some skull bits that aren’t Malawisaurus, and No. 89-78 might belong to Karongasaurus or another, as yet undescribed sauropod. But I gotta tell ya, that vert looks like nothing else I’ve ever seen. The parapophysis in  particular is immense; even most Apatosaurus cervicals don’t have parapophyses that massive. Throw in the apparently apneumatic centrum and the shark-fin neural spine and you’ve got something that I’m not even 100% sure belongs to a sauropod, although if it’s not a sauropod then I don’t even know where to begin. The scale bar in the Jacobs et al. figure is 50 mm, which is 5 cm or 2 inches, so the vert is more than a foot long, which pretty much rules out a non-sauropod identity. I’m lost on this one; your ideas are welcome.

Also, where the heck is No. 89-78 now, and how come nobody has mentioned it in the past 16 years? Or has it been mentioned and I just missed it? Any help here would be hot.

References

7 Responses to “Mystery of the missing Malawisaurus vertebra”

  1. Rutger Says:

    Thank you for pointing this out! A while ago I attempted a Malawisaurus skeletal reconstruction and gathered all material I could possibly find, including the two papers that you mention here. Ultimately, I did not pursue the project, but I did run into the problem of this mystery vertebra, because it did not appear to fit in the sequence of the other cervicals.

    Good luck on establishing its identity!

  2. Nathan Myers Says:

    I’m gobsmacked that someone can leave the field and go incommunicado and thereby prevent other people from publishing their results. How can it be that being deliberately incommunicado doesn’t automatically release you from any obligation to obtain their permission to publish your work?

  3. Matt Wedel Says:

    I did run into the problem of this mystery vertebra, because it did not appear to fit in the sequence of the other cervicals.

    Good to know I’m not crazy! Makes you wonder how many of these little mysteries are lurking around, that more than one person has noticed but no one is talking about.

    How can it be that being deliberately incommunicado doesn’t automatically release you from any obligation to obtain their permission to publish your work?

    Maybe it does, or should. But I’m playing it safe. Elizabeth and Lou and Dale are all friends and I prefer to err on the side of caution.

    Plus, this ain’t the only pile of data I have sitting around, sadly. I am getting some of this old stuff done and out, but I really need some grad students to hand some of these projects and push them to completion. Watch this space.

    Really, it’s kinda stupid that I haven’t just asked Lou, about the mystery vert and about publishing the CT scans. I see him every year at SVP and we always talk at least briefly. If nothing else, this post ought to serve as a reminder to me to just ask this year. The post should in no way be taken as a negative comment on the published work on Malawisaurus, which has all been excellent. It’s just one of those little loose threads that needs tracking down and tying off. And possibly it has already been tied off and I just don’t know about it.

    You know that the fastest way to get information on teh intert00bz is not to ask, but to post the wrong information and wait for someone to correct you. So I therefore declare that No. 89-78 is the holotype of Barosaurus and this has been known since Thomas Jefferson described the taxon in 1609. Now, someone prove me wrong. I dare ya!


  4. The parapophyses of Malawisaurus are long, thin plates, much like those of Sauroposeidon. This is in sharp contrast to the huge and nearly circular parapophyseal stump on No. 89-78.

    Comparing plural to singular, I note.. is the other side of No. 89-78 known.. to be the same? I look and – maybe ignorantly – wonder, could the odd parapophysis be abnormal (diseased/injured/malformed)? It would be rash for me to assume that, but, might it be apt to consider it as a possibility here?

    Incidentally this is an opportunity for me to muse out loud: how interesting it would be to see, collected together, descriptions of injured/aberrant individual specimens; especially ones that had healed, or, appear to have been fatal.

    And not just for sauropods; for all taxa! Fossil and recent!

  5. Nathan Myers Says:

    Maybe it’s just because the images are not very detailed (and I’m an ignorant sot), but the mystery vert seems to me to resemble image H more than a little, once I lop off the bits corresponding to those snapped or abraded off of 89-78.

  6. Nima Says:

    It looks like it’s simply missing the tip of the neural spine if it’s Malawisaurus.

    But the parapophysis is odd AND the centrum is unusually short, with the rear cotyle being vertical instead of slanted as in the Malawisaurus sequence.

    So it’s likely another creature…. I venture to guess it’s a primitive holdover from the days of the Turiasaurians. It looks almost too primitive to be a neosauropod or perhaps even a eusauropod…


  7. […] From Mystery of the missing Malawisaurus vertebra, this alleged vertebra of that taxon from Jacobs et al. (1993:fig. 1), which completely fails to […]


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