Monday, October 6, 2014

Spinosaurus-world Problems

Spinosaurus aegypticus, lord of the Kem Kem river system.

September 12th saw the publication of Ibrahim et al.’s new reconstruction of Spinosaurus aegypticus, surely one of the most famous and mysterious of all dinosaurs. The authors designate a neotype, assign a bunch of previously indeterminate material to S. aegypticus, synonymize “Spinosaurus maroccanus” and “Sigilmassassaurus brevicollis” into S. aegypticus, and offer up a bizarre interpretation of the whole animal. No longer confined to wading in rivers and snatching up fish a la Suchomimus, Spinosaurus is now a proper semi-aquatic dinosaur that the authors compare to early whales. Aside from being published in Science, National Geographic appears to be paying the bills and fabricated a massive skeletal reconstruction and life-size model. As can be expected, there was much media fanfare surrounding the publication and public unveiling.


But in the paleo-bloggosphere, things were not so rosy. Brian Switek provides an excellent starting point. Scott Hartman blogged about his problems with the new reconstruction, specifically regarding the hindlimbs, which made this 50-foot behemoth look like a dinosaurian dachshund (or perhaps corgi). Ibrahim et al. suggested that the hindlimbs were so short that Spinosaurus would have been quadrupedal on land. Hartman found some errors in the published measurements and attempted a corrected reconstruction, which certainly looked better.

Jaime Headden discussed several issues including the hind limbs, problems with quadrupedality, questions regarding the synonymy of other specimens, and whether the designation of a neotype was actually warranted.

Andrea Cau produced an impressive series on the new discoveries—if you can handle some garbled Italian-to-English translation, I higher recommend it. In particular, Andrea criticizes the authors for not making the digital Spinosaurus bones freely available for others to investigate and test.

There was even a discussion on SV-POW! about National Geographic’s official artwork by Davide Bonadonna (above), whose beautiful image brought to mind Brian Engh’s previous semi-aquatic Spinosaurus art.

More discussions were carried out on Facebook, of course. The backlash was severe enough that the authors actually responded on Scott Hartman’s blog. I encourage you to read it, although the finer points are: (1) the hindlimbs are properly scaled; and (2) wait for the monograph, which is being written. These people are all far smarter than me regarding the taxonomy, anatomy, and minutiae of the “new” Spinosaurus, so I make no claims regarding the accuracy of their statements. But I wanted to talk about some things I’ve personally found troubling about the whole rigmarole.

This image comes from the Supplementary File. The arms are lower than the legs.

Hype: As I mentioned, National Geographic is basically footing the bill for an enormous rebirth of Spinosaurus aegypticus, with a new exhibit called “Spinosaurus: Lost Giant of the Cretaceous” in Washington D.C.’s National Geographic Museum. On October 16, Ibrahim & Sereno will be giving a talk about the discovery (sure to be fascinating in its own right), although the summary for the event is (of course): “Discover a prehistoric monster bigger than T.rex with paleontologists Paul Sereno and Nizar Ibrahim."

Tyrannosaurus rex: barometer for the size and ferocity of all prehistoric animals. Similarly, the cover story in October’s issue of National Geographic says “MOVE OVER, T.REX!” Christ.

It probably wouldn’t be difficult to find previous issues of Nat Geo covering Carcharodontosaurus and/or Giganotosaurus with similarly melodramatic taglines. At their press website, we learn immediately that Spinosaurus was a “Massive predator was more than 9 feet longer than largest Tyrannosaurus rex.”

Here are some other more interesting headlines for your consideration, Nat Geo:
Spinosaurus revealed as semi-aquatic fish-eater!
• Massive carnivore had dachshund proportions!
• Giant sail-backed piscivore stalked Africa’s rivers!
• Lost for a century, Spinosaurus finally revealed!

Ultimately, the exhibit is making claims that cannot, at this time, be independently verified—they’re writing scientific checks that can’t be cashed, as it were. I feel this is irresponsible, but recognize that the commercial aspect demands a certain amount of timeliness. Still, the media blitz probably could have waited until the publication of the monograph—the initial two-page (sigh) Science publication could have come out “under the radar” and complaints lodged, like those detailed above, could have been addressed in the monograph. This would have, to my mind, resulted in a much stronger set of hypotheses from Ibrahim et al. At this time, however, the National Geographic exhibit runs the risk of misinforming or misleading the public, a practice I abhor.

Will they make changes based on the published monograph? Has Sue gotten a real wishbone yet? I didn’t think so.

Venue: As I have “come up” in paleontology, I’ve learned that, for many reasons, Nature and Science may, in some ways, be the WORST places to publish new discoveries, especially those of this caliber and high claim. The draconian page count requirements result in papers that are often shorter than brief blog posts, and authors are forced to rely on Supplemental Information files which may or may not provide all the information they (or the audience) want to see conveyed.

It was also published in a weird offshoot of Science—something called Sciencexpress, which I was annoyed to find my professor wife does NOT have access to (but she does to Science). Maybe I’ll talk about OA another day, although they cover it pretty extensively over at SV-POW.

Point being, it’s hard not to feel like the authors were improper in their choice of publisher. I can’t imagine that a more suitable journal like Journal of Vertebrate Paleontology or Cretaceous Research would have too many misgivings about publishing such an important paper, and they do not have the restrictive page count requirements that Nature and Science do. Of course, the dream would be for this research to have been published in something like PLOS ONE, Peer J, or Acta Paeontologica Polonica, which are all champions of OA publication. Maybe they don't have the visibility that Science does, but paleontology is not a HUGE field--people know where important things are published, especially in this age of social media.

The cynic in me says that Science was chosen for primarily for its high-impact status as opposed to its usefulness to the field as a whole, and the careers of all the authors will get a boost—good science be damned. This is NOT, I should emphasize, the fault of the authors. This is a problem with academic publication generally: that Science and Nature have such cache which is inversely proportional to their practicality is a cultural problem that must be treated in a very specific way—don’t publish in these journals. The impact factor of other, “lesser” journals will only increase once people start publishing in them more frequently so that other authors cite those articles more often. That budding scientists may have to choose between boosting their career with Nature and Science and doing “the right thing” is an indictment of the entire culture of academia. This does not only apply to paleontology, either, but across academic disciplines. This is a discussion for another day, though.


The "swimming pose" which has caused so much hand-wringing, from the body of the paper.

Ambiguity: Basically, if the Ibrahim et al. are unhappy that the Internet is pointing out a number of ambiguities in their paper, they have no-one to blame but themselves. The goal of any scientific communication is to be clear, concise, and present repeatable results. Let me give you one example of how ambiguity is a problem here. I’ve already linked to Scott Hartman’s excellent discussions about Spinosaurus’ measurements, specifically regarding the femur and ilium, and the author’s response, but here is a line from that response, one that I feel is instructive (and troubling): 

“Also, in the 3D model, the femur is not hanging straight down—it is angled outward/laterally slightly and so foreshortened slightly in lateral view, making it look shorter.”

The 3D model they reference is the colorful 3D model shown above that appears in the Science paper that they themselves created to give an ambiguous view of the femur.

That the femur was “foreshortened slightly in lateral view” was not explicitly stated in the paper itself, so now we come to one of those things I feel like I should not have to say out loud:

The purpose of every diagram, figure, measurement, and picture in a scientific paper is to unambiguously educate the audience about the DATA, present said data, and relay your interpretation of that data. There is NO REASON to pose your Spinosaurus skeleton a way that results in an ambiguous reading of the femur length in a scientific paper.

I don’t care if the skeleton is posed in a swimming posture that’s in line with your bold new interpretation of Spinosaurus. It was an irresponsible choice, and you can't complain about your own damn error in judgement. Apologize and move on.

Quadrupedality & Other Oddities: The authors offer a semi-aquatic mode of life for Spinosaurus. This idea is not new, but Ibrahim et al. are taking it further than usual. Given the short legs—which they confirm in the Hartman post are real—and long body, the animal’s center of balance (COB) would have precluded bipedal locomotion. The authors recommend quadrupedality (although Duane Nash has a unique suggestion). From what we currently know of theropod hands and wrists, quadrupedality is NOT an option—notice that derived therizinosaurs evolved an awkward-looking upright posture rather than dropping down to all fours.

Is it possible that Spinosaurus knuckle-walked? That would also be without precedent. AFAIK, knuckle-walking evolved only a few times in mammals: apes, sloths, and chalicothereiines. Because this was a Science paper, the authors didn’t have any room to discuss how quadrupedality would work in the main text, but they didn’t talk about in the Supplementary Information either. They also give it a distinct two-humped sail without detailing the reasoning behind that decision. Jaime Headden and others have discussed the uncertainties regarding the order of the dorsal vertebrae and the resulting differences in sail shape. If Ibrahim et al. make a strong case for their double-humped sail, I missed it. “Wait for the paper,” will, undoubtedly, be the standard response. I can respect that, to a point. Guys, if Science wasn’t going to let you show your work, maybe don’t publish there?

This post is already getting ridiculously long, as I wrote it over the course of a week. My goal was to provide a summary of the post-publication discussion regarding Spinosaurus and to elucidate the considerable uncertainties regarding its proposed lifestyle and reconstruction—with some jabs at how it was handled in the media. I hope I’ve done that, and my next post won’t be quite so long or link-heavy. No, we’ll be talking about a purely subjective subject, but one I feel quite strongly about: giving place-names to fossil organisms—a practice I feel is intellectually bankrupt.

7 comments:

  1. Just a minor point - Science Express isn't a weird offshoot of Science. It's just the advance online publication of Science and papers there usually come out completely in Science a few weeks later. You are right that it requires an extra level of subscription to read though.

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  2. good to have you back!

    I find that the "wait for the paper" line is sometimes used as a means of trying to to make criticism off limits. I got it on my blog when i discussed the "Toroceratops" debate. I know publishing takes a long time. But if you put any information into the public realm (blogging, supplementary material, brief mention in a previous paper) then it's fair game. If we are supposed to "wait for the paper", it could be years before any critique of those ideas could be leveled. In the mean time, are we supposed to just twiddle our thumbs while those ideas run around the public and scientific conscience unchallenged? "Wait for the paper" seems like a cop out, rather than an invitation for critical thpught like science is supposed to thrive on.

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  3. Knuckle walking is also known in anteaters and platypuses. I do like the idea of pangolin-like bipedality for Spinosaurus, as suggested by Darren Naish.

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  4. Glad to see you back & glad to see you covering Spinosaurus (which, given everything I've read, is even more mysterious now than it was b-4 Ibrahim et al. 2014). I probably won't know what to think until we find some relatively complete & definitely associated remains.

    -Hadiaz

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  5. "AFAIK, knuckle-walking evolved twice in mammals: apes and chalicothereiines."

    What about sloths?

    That aside, I do agree with pretty much everything you've written here, especially about what totally crappy venue Science is for actual science. It should be called The AAAS Journal of Press Releases. The good thing here is that Nizar et al. have committed themselves to doing the descriptive job properly in a real journal. I suppose we can hardly blame them for accepting the career boost of publishing an illustrated abstract first.

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  6. It seems you may have missed the second response of Ibrahim et al. on Mark Witton's blog. Also of note is that Andrea Cau's hypothesis for Spinosaurus posture may very well refute the idea that Spinosaurus could not have assumed a bipedal posture. Personally, I subscribe to an amalgam of Andrea Cau's hypothesis and Darren Naish's hypothesis that Spinosaurus locomotion was analogous to that of pangolins.

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  7. Thanks for quoting my interpretation.
    I'm very skeptical that a several tons animal could walk efficiently with a pangolin-like posture or a knuckle walking. All secondarily quadrupedal dinosaurs followed a similar trend in forelimb evolution to support the large mass, involving forearm and hand modifications departing far from the plesiomorphic raptorial hand of theropods.

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