Saturday, November 24, 2012

GUEST POST: Felipe Pinheiro and the Raiders of the Lost Palate

2012 has been a good year for pterosaurs, with several new taxa and important papers being published. This trend continued this week with the description of a fragmentary but intriguing pterosaur palate from the famous Cretaceous Santana Formation of Brazil, authored by Felipe Pinheiro and Cesar Schultz of the Universidade Federal do Rio Grande do Sul. Avenida Bento Gonçalves, Brazil, and Bayerische Staatssammlung für Paläontologie und Geologie, Germany, respectively (image of the new material is shown above. Image courtesy Felipe Pinheiro). Felipe asked if we could big up the paper here at the Pterosaur.Net bog, but I'm a little too pushed for time to write a post worthy of the article, which not only describes the specimen but sheds much needed light into pterosaur palatal anatomy. Felipe was kind enough to provide his own illustrated summation of the story however, so we could still cover the paper here at the blog. On that note, I'll hand you over to our guest blogger, and be sure to check out his open access paper for more details on this new discovery. 

MPW 24/11/12


The fragility of pterosaur skeletons is always working against us, the paleontologists devoted to understanding these flying archosaurs. Independently if our research deals with systematics, anatomy or paleobiology, we’re often confronted with the fact that our research subject is badly crushed and a great deal of useful information is simply lost. A very good example of this issue is the pterosaur palate: although new pterosaur taxa are being published all the time, only a handful of well-known specimens have this structure preserved, thus, limiting our knowledge of its anatomy and evolution within the group. Luckily, some rare sedimentary deposits were kind enough and maintained the original, three-dimensional shape of their fossils, allowing the study of otherwise inaccessible anatomical features, like, of course, the pterosaur palates. (Pterosaur specimens showing palatal regions below. Image courtesy Felipe Pinheiro)

Our understanding of pterosaur palatal anatomy changed considerably after the recent work by Attila Ösi and colleagues (2010). Analyzing pterosaur palates under an evolutionary perspective and utilizing the Extant Phylogenetic Bracket as a tool, the authors identified homologue structures between pterosaurs, birds and crocodiles, demonstrating some bones that were misinterpreted throughout the literature. The best example is the conclusion that, in pterosaurs, most of the palate is composed by palatal blades of the maxillae, instead of the palatines. Although this identification was also proposed by some old researchers, like Newton (1888) and Seeley (1901) and, more recently, Peters (2000), common sense was still that the palatines composed most of pterosaur palatal surface.

As the work of Ösi et al. (2010) was mainly focused on stem “non-pterodactyloids”, especially Dorygnathus, a new look on pterodactyloid palate was still needed and this is the main subject of our new paper, titled “An Unusual Pterosaur Specimen (Pterodactyloidea, ?Azhdarchoidea) from the Early Cretaceous Romualdo Formation of Brazil, and the Evolution of the Pterodactyloid Palate”.
Besides describing a new fragmentary (but interesting) palate from the Romualdo Formation (the Early Cretaceous concretion-bearing strata of the Santana Group, northeastern Brazil), we analyzed and redescribed a number of well-known pterosaur specimens with palatal preservation, such as “Pterodactylus” micronyx, Anhanguera and Pteranodon. Also, the palate of the Iwaki Tupuxuara specimen is described and illustrated for the first time. As a result, our work shows that pterodactyloids had often complex palatal morphologies with, sometimes, interesting “reversions” to the non-pterodactyloid condition, with three pairs of lateral openings. Also interesting is the extreme reduction of elements in some taxa, such as the almost vestigial ectopterygoids of anhanguerids. (Possible evolutionary pathways of the pterosaur palate shown below. Image courtesy Felipe Pinheiro.) 

This morphological disparity is probably an evidence of complex feeding habits among derived pterodactyloids, with ecological implications that is, presently, the research subject of our working group, at the Universidade Federal do Rio Grande do Sul, Brazil.

I hope you all read our paper (don’t worry, it’s open access). We’re opened to all kind of criticism and discussions by my personal e-mail:

Felipe L. Pinheiro
Laboratório de Paleontologia de Vertebrados, Instituto de Geociências, Universidade Federal do Rio Grande do Sul.

  • Ösi A, Prondvai E, Frey E, Pohl B (2010) New interpretation of the palate of pterosaurs. The Anat Rec 293: 243–258.
  • Newton ET (1888). On the skull, brain and auditory organ of a new species of Pterosaurian Scaphognathus purdoni), from the Upper Lias near Whitby, Yorkshire. Philos Trans R Soc Lond B Biol Sci 179: 503–537.
  • Peters D. (2000). A re-examination of four prolacertiforms with implications for pterosaur phylogenies. Riv Italiana Paleontol Strat 106: 293–336.
  • Seeley HG (1901) Dragons of the Air: an account of extinct flying reptiles. New York: Appleton & Co.; London: Methuen & Co.

Monday, November 12, 2012

Pterosaur fact checking

I will keep this brief, since Mark already did a great job of responding to the media release from the recent Chatterjee et al. presentation.  One thing to look for in any sort of functional morphology argument is whether the anatomy, the numbers, and the behavior all match up.  One reason the Chatterjee et al. abstract is so immediately concerning is that their own information doesn't jive internally.

Example 1: one of their concerns with the quad launch hypothesis is clearance for the wings after launch.  Now, I've calculated the expected clearance and everything seems fine, but that doesn't mean I'm right.  Maybe someone will find an error at some point.  What is clearly not going to be true, however, is the idea that keeping the feet on the ground (biped running launch) is going to give more clearance than a leap.  It simply isn't possible to get more clearance by not jumping (it might be true that jumping still isn't enough, but it's not going to be worse).  So Chatterjee et al. have a mismatch between their own conclusions and their arguments with the competing model.  The numbers and the behavior don't match up.

Example 2: Chatterjee et al. argue that pterosaurs can't work as scaled up bats, and argue instead that they should work like scaled up birds.  Anatomically, pterosaurs don't match either of these, so the bat argument is a straw man, and the bird argument is moot.  The anatomy and the behavior don't match up.

These are the sorts of arguments that raise red flags in scientific discourse.  On a final note, there are some basic fact checking items that should be looked out for, such as claims about living animals.  From the media story, Chatterjee is quoted as saying "Like albatrosses and the Great Kori bustards, which weigh 20 to 40 pounds, ground takeoff was agonizing and embarrassing for Quetzalcoatlus."

Aside from the problem with the pterosaur analogy, there is the obvious problem that Kori bustards don't have trouble taking off (though they might find it embarrassing; I haven't asked them).  In fact, Kori bustards can leap into flight at a steep angle.  Check this out.  Yes, the bustard tries running to escape, first, but when pressed, it just leaps into the air.  No big runway, no "agonizing" takeoff.  In fact, there is no correlation between running launch and size in living birds or bats.  More on that some other time, but in general, if a YouTube search quickly demonstrates that your commentary is flawed, that's a bit worrisome.

Sunday, November 11, 2012

How giant pterosaurs are struggling to take off from the sinking ship of science journalism

This week, it emerged that the giant azhdarchid Quetzalcoatlus was an atrophied, under muscled animal that was weak and inefficient at takeoff, and could only launch through use of running bipedally with flapping wings, headwinds and downward sloping ground. The newly proposed idea of quadrupedal launch, where pterosaurs became airborne via powerful leaping with all four limbs (Habib 2008) is hokum, being the stuff of fantasy and overly zealous application of bat launch strategies to flying reptiles. 70 kg is the maximum mass that these giants and all other flying animals could achieve, and recent discussions that they were considerably more massive (Paul 2002; Witton 2008; Henderson 2010; Witton and Habib 2010) are plain wrong.

At least, that’s what a recent press release by Sankar Chatterjee and colleagues would have us believe. (Above image: the pterosaur launch battleground. At top is a quad launching Hatzegopteryx, a giant azhdarchid; below, is a bipedally launching Quetzalcoatlus using taxiing, headwinds and a slope to become airborne. Hatzegopteryx is from Witton [2013]; Quetzalcoatlus is from Chatterjee and Templin [2004]) Speaking at the Geological Society of America 2012 conference recently held in Charlotte, N.C., Chatterjee (of the Museum of Texas Tech University; most notable within recent pterosaur research for his contribution of windsurfing tapejarids to the Attenborough pterosaur documentary) and colleagues outlined why he considers much of the recent discussions of giant pterosaur flight dynamics to be flawed in a short presentation, and decided to disseminate their ideas further through the public press. Although the press reports for this story have been relatively widespread, the response from pterosaur researchers to this release has been generally negative, largely because the claims do little to address the recent developments and hypothesis shifts within pterosaur flight studies and largely parrot the findings of Chatterjee and Templin’s 2004 paper on pterosaur flight. Pterosaur.Net’s own Mike Habib, one the key modern researchers on pterosaur flight, offered this take on the release:

Unfortunately, this looks like the argument comes down to ‘but we got a different answer in 2004!’ Yes.  We know, and for five years I've explained why it is probably wrong.  Oh well.”

Chatterjee et al.’s abstract and press release do not explain why the many arguments supporting pterosaur quad launch (see here and here, for a start) are problematic or why arguments and methodologies to estimate relatively high masses for pterosaurs (here) are incorrect. Instead, they’ve decided that such scientific rigour doesn’t matter, and gone straight into informing the public that giant pterosaurs took flight in the way described in their presentation, and that all other opinions on the matter are wrong.

By bigging up their abstract rather than a peer-reviewed publication in which their methodological details and discussion are explained in detail, Chatterjee et al. have given the impression that their work is more scientifically credible than it actually is. Science journalists have lapped the release up, presumably because giant pterosaurs are cool, but they have not mentioned the lack of a detailed peer-reviewed study behind the findings, nor (in the majority of cases) bothered to find out what other palaeontologists make of the story. This is not the first time this sort of outreach has happened. The proceedings of other conferences and un-reviewed articles have given us infamous press stories such as the ‘Triassic kraken’, vampire pterosaurs, and the suggestion that all dinosaurs were aquatic. And these are just examples from recent memory.

As a scientist concerned about effective and accurate scientific outreach, I find this sort of journalism very worrying. I have no problem with off-kilter ideas like those proposed by Chatterjee et al., but their desire for press attention without applying appropriate scientific rigour is extremely concerning. They have not documented their studies in a scientific paper, sought the opinions of other experts in peer review to construct a scientifically sound hypothesis and news piece. Instead, they went straight from the ‘idea’ phase of their project to media broadcasting, which, as I see it, has three effects. Firstly, it risks misleading the public if their ideas fail to meet scientific scrutiny (most of the ideas mentioned thus far in this article are guilty of this, and I strongly suspect the same is true of the Chatterjee et al. story). Secondly, it undermines the integrity of the scientists behind the story. The idea that “any publicity is good publicity” does not apply to scientists. Within academic circles, you become “the guy who went public with [crazy idea]”, which doesn’t do your reputation, or that of your institution, any favours. Thirdly and perhaps most importantly, such practises undermine science generally. It’s no wonder that palaeontology is often viewed as a speculative and unsubstantiated discipline when a lot of our press work concerns unsubstantiated, often ‘fringe’ or highly controversial ideas being presented as credible hypotheses. This only creates confusion among people as to what the leading hypotheses on given topics are or, when press stories have gaping holes in logic (e.g. the Triassic kraken, aquatic dinosaurs) show scientists as bumbling, foolish individuals incapable of using common sense.

This is a serious problem which we, as scientists and scientific communicators, need to address. Many people are generally sceptical of scientists and their conclusions, concocting up ideas of scientists in scaremongering conspiracies for grant money, or seeking media attention to justify their employment at publically funded museums and universities. The manner in which scientists frequently present unsubstantiated work to non-academics does little to help restore our reputation with these individuals. While it’s of fairly trivial concern whether the public, or anyone for that matter, knows the ins-and-outs of pterosaur launch, all scientists need to think about the broad perception of science by the public. Scientists researching our many severe, modern crises need to be taken seriously, and press reports that expose incomplete or shoddy scientific work negatively impact this perception. Fairly or not, many people, tar all scientists with the same brush (for proof, check out the comments section on any science story publicised by the Daily Mail). We should be working to enhance the reputation of science among the public so that scientific opinions on critical issues like our on-going losses of biodiversity, climate change, sustainability of our lifestyles, energy conservation, and other real, genuine problems are trusted and taken seriously. Scientists leaping for the press with hypotheses that have yet to be suitably tested only present scientists as attention seekers, incompetent or both, and we cannot afford to perpetuate this idea further.

Of course, the fault does not only lay with the scientists. Science journalists also need to raise their game, becoming more circumspect when following and writing up of press stories, noting the state of the research involved, gauging its context within its field and, perhaps in some cases, ignoring clearly bogus, fringe reports entirely. I have worked with a great number of people involved in the scientific media who clearly do not have any interest in science beyond their job, and these are the worst people to be trying to turn the sometimes complex hypotheses of scientists into digestible material for laymen. As Brian Switek shows on a daily basis at Dinosaur Tracking, you become an exemplar science journalist not by just being a deft writer, but you have to give a crap about science too. Failure to fact check and presenting ideas inaccurately is miscommunication, which is clearly an enormous failing for an individual employed to dissemination of information.

In short, we need to stop thinking about scientific outreach as purely an exercise in getting the most attention possible to our research or science news articles. These short-term goals are damaging to science as a whole, which is what science communicators are meant to promote. Science communication is an opportunity to educate non-academics with new and exciting results of good scientific practise that have helped develop our understanding of the world and our place within it. We should take the responsibility that this task requires fully and seriously if we want our scientific voice to be listened to.

  • Chatterjee, S. and Templin, R. J. 2004.  Posture, Locomotion and Palaeoecology of Pterosaurs. Geological Society of America Special Publication, 376, 1-64.
  • Habib, M.B. 2008. Comparative evidence for quadrupedal launch in pterosaurs. Zitteliana, B28, 161-168.
  • Henderson, D. M. 2010. Pterosaur body mass estimates from three-dimensional mathematical slicing. Journal of Vertebrate Paleontology, 30, 768-785.
  • Paul, G. S. 2002. Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds. John Hopkins University Press, Baltimore, 472 pp.
  • Witton, M. P. 2008. A new approach to determining pterosaur body mass and its implications for pterosaur flight. Zitteliana, B28, 143-159.
  • Witton, M. P. 2013. Pterosaurs: Natural History, Evolution, Anatomy. Princeton University Press. [In press]
  • Witton, M. P. and Habib, M. B. 2010. On the size and flight diversity of giant pterosaurs, the use of birds as pterosaur analogues and comments on pterosaur flightlessness. PLoS ONE, 5, e13982.