The Broken Jaw of Banguela


In my last post, I introduced Banguela oberlii, a new, toothless dsungaripterid pterosaur.

Banguela oberlii, ©2013 Sergey Krasovskiy, used with permission.

Banguela oberlii, ©2013 Sergey Krasovskiy, used with permission.

But a pterosaur, for us, doesn’t end at a story of what the animal is, or was. It continues through how it became, and why. Animals have an explicit existence: they are. But fossils might be, and part of the trick about fossils is they have to be found, recognized, recovered, preserved, and conserved. They have to end up in the right hands.

The holotype and only specimen of Banguela oberlii is NMSG SAO 251093, and it almost didn’t get to be the holotype – or rather, a holotype. Sometime before 2005, fossil hunters from around the Chapada do Araripe plateau in northeastern Brazil acquired a small specimen of pterosaur jaw from a limestone concretion. As is often the case with these things, a problem which plagues Brazil’s fossil collecting, the specimen ended in the hands of private collectors and overseas, at which point it was nearly completely prepared, which turns out to be a good thing in the long run.

Banguela oberlii jaw figure 2

NMSG SAO 251093, holotype and only specimen of Banguela oberlii Headden & Campos (2014). Specimen in dorsal, left lateral, ventral, and right lateral views, and then at breaks in the fossil in the midsection (at a-a) and at the caudal remnant. The two mandibular shelves are apparent in F, where they surround a “mandibular fossa.” This feature deserves far more attention than it has received. [This figure was produced for the paper, but had to be rendered in B&W for production purposes, and is here shown in its original color.]

Fossil collection from the Chapada do Araripe is lucrative. There’d be no market to keep it going if this weren’t the case. Owning a beautiful skull of such an animal, sometimes fantastic in their strangeness, can be a sign of prestige for some. When collectors get their hands on these specimens, the specimen’s future becomes ambiguous. Most may pass the specimen off as “lost.” Irritator challengeri, a spinosaur from the Romualdo Formation of the Chapada do Araripe, nearly met this fate. It was privately collected, sold, and eventually ended up in the hands of Europeans. It’s in a scientific institution now through the providence of researchers. Researchers who paid money.

Money traded for fossils has been a bugbear of paleontology since Roy Chapman Andrews returned from the 1922 Mongolian paleontological expeditions – sent there by Henry Fairfield Osborn to search for central Asian human origins because racism – and brought with him fossilized eggs and skeletons. Now, it’s an anecdote, but when asked what the value of these specimens he returned were, Andrews responded by citing a monetary value. This gave the public the idea that fossils can equal money, notably with the sale of Sue and the entire Erik Prokopi affair.

Irritator challengeri‘s case is more than a little frustrating, showing us as it did that not only doctoring the fossil (it was modified to be made up like a crested pterosaur head, as occurred to many of the Chinese fossils farmers sold to institutions, leading famously to the “Archaeoraptor” brouhaha) but also that it must to be acquired from a trade show floor lest it end up somewhere where its fate is ambiguous. Caupedactylus ybaka is another, more recent, specimen from Brazil acquired from a trade market, but implied to be from the Romualdo Formation. Caupedactylus ybaka actually came out towards the end of preparation of the study, but a quick check told us it wasn’t going to be very important when it came to assessing Banguela oberlii directly. (It does matter in the larger analysis of Thalassodromeus sethi, but not for our new taxon.)

Specimens without provenance data are problematic, as without that data we lose a lot of information. Fortunately, material like this can retain important data that provides clues. Matrix retained with the material can be used to sample microfossils, sediment composition, and color, which can be matched pretty closely to the formation from which it comes. The Romualdo has a characteristic light brown/tan coloring to it, whereas the formations around which the Romualdo outcrops (Crato and Ipubi) are distinctly darker and finer. Romualdo specimens are often preserved in three dimensions, sometimes in perfect condition, while Crato specimens often end up flattened or smooshed; the differences are striking. So we were pretty certain the specimen was Brazilian, from a limestone concretion, with an infill of muddy sandstone inside the holes of its jaws, and that the specimen came from the Araripe Plateau; and this points to the Romualdo Formation. But even were we wrong on provenance, we knew the specimen was distinctive enough to survive scrutiny had it come from anywhere else, even Asia along with other dsungaripterids.

NMSG SAO 251093, like many of such fossils, ended up in the hands of private sellers. But this story (like Irritator’s) has a positive outcome – how can you guess?

It was purchased by Swiss collector Urs Oberli, whose collection is well-known in Switzerland and Germany and to many pterosaur workers. Oberli, whose name graces the epithet of Banguela oberlii, placed the fossil into his private collection, labeled “SAO,” but into public display at the local museum, the Naturmuseum St. Gallen in St. Gallen, Switzerland (the “NMSG” in the specimen’s name; the “SAO” refers to the collection of Urs Oberli). It was in this collection where André Veldmeijer noticed the specimen and described it. Veldmeijer has discussed a lot of other material in the SAO collection, but this one is the most interesting to me, though another is a nearly complete skull of a (toothed) pterosaur and quite excellent in its preservation.

NMSG SAO 251093 has been cast multiple times, and copies are deposited around European and Brazilian museums. Hebert Campos has one. One was used by Stu Humphries and colleagues to examine the use of the jaw in skimming (it’s not very good at it). At this time, it was called “SAO 251093.” As we were working on Thalassodromeus sethi, we noticed this specimen. It had been mentioned in another publication, a test on the hypothesis of whether Thalassodromeus could skim-feed in which it stood in for that species. But beyond that, nothing. The old practice of merely mentioning a specimen, “describing” it, without acknowledging proper accessioning and preservation. Oberli had done a good job: the specimen was kept in a well-prepared display, and a little matrix remains attached to the specimen, providing scientists in the future the ability to directly examine provenance, if possible. We lacked the ability to access the material in a timely manner, a problem that we aim to correct, but our access to data on the specimen itself, restricted to its morphology, is nonetheless more than we’d hoped for. Merely noting something in an offhand manner might be useful for some things, such as a casual review, but our study was showing us this specimen mattered.

Specimens in private hands make poor study specimens. It would be difficult to confirm observations if the fossil vanished from science, its only remnants two papers and an historical footnote. Once Hebert and I knew this specimen was important for discussing Thalassodromeus, and that the specimen might be a new taxon, I contacted Oberli about the situation. And as you might guess, the situation had been solved: “SAO 251093” became NMSG SAO 251093 – the specimen was accessioned into the Naturmuseum St. Gallen, the place of its residence all these years, now its permanent home. This meant that work on the specimen could continue and, if necessary, more work on it can be done after our paper was out. We needed to talk to Oberli anyway, as we were intending to publish in PLoS ONE (a story I will get into later), and the journal had a policy that all material discussed within had to be publicly reposited, available; it wasn’t just about taxonomy. And it’s a point I’m a stickler for: I don’t like talking about specimens that will merely end up lost to science, or whose future is ambiguous. This specimen was important to our work, and has been the subject of other analysis, so we needed to handle its permanency issues.

But About that Name…

It took little convincing to provide this. Oberli transferred the specimen to the museum; he no longer owns it. And in return, his name graces the taxon. This isn’t unusual: benefactors for work and materials often get an honorific label attached to the specimen or new taxon which they provide for. But I should make this clear: we weren’t certain this specimen could be the basis of a new taxon, and we let Oberli know this. Even after primary study had been completed, I was unsure whether the specimen should be named. I have drafts still in near final form where the nomenclature was stripped, and during review considered final submission in this manner. But I am actually glad the name is there now — not because I get my name attached to a taxon, but because this allows a seemingly innocuous but important specimen to be more easily referenced in the human mind: we like our categories and labels, and for us, the “specialness” of the name is greater than that of the alphanumeric series we give specimens.

I have mentioned how I would prefer not to name taxa, and that was the case here. Based on such a small bit of an animal, what could the value be? But because I’m a jaw kinda guy, I delved deeper. The mandible, as it turns out, has received limited attention in analysis, and that meant if plugged into phylogenetic analysis there’d be very little that could be said. So I started quantifying the heck out of the specimen. This meant trying to determine what was meaningful about its different parts, and a major problem was that almost NO one had looked at the unusual presence of two sets of symphyseal shelves on the mandible.

This is a topic for another post, one in which I discuss the things animals use to bite with, but let me say this: Few pterosaur workers take a deep, developmental biological aspect to their analysis of pterosaur anatomy. Part of what interests me is there is a lot of untapped data involving the jaws of pterosaurs, and that’s something I’m going to try to make a priority of as I work on the jaws of sauropsidans in general (and try not to step on some peoples’ toes).

NMSG SAO 251093, Banguela oberlii.

You will notice that in the paper, we do not use the common phrase “gen. et sp. nov.” or “gen. nov., sp. nov.,” but instead the far less conventional “tax. nov.” In fact, the word “genus” appears nowhere in the paper except to point out it doesn’t appear anywhere else; and for that matter, “species” also only appears there. I’m okay with using species, but the problem lies in “genus,” the ranked taxon. We did it this way to hold true to my argument that ranks are bunk, a concession the reviewers felt was permissible. That said, registration of this name in ZooBank required use of “genus” and “species” fields, and that then can be someone’s concession on form. So thus you get a single name, Banguela oberlii, that approximates the form of a genus-species couplet; but it would be possible to say this is a species at least, with a praenomen. I like the elegance of the couplet form, and the information it conveys, which has been one of the strongest positives for the old system of naming animals this way. And of course, because of his generosity, we honored Urs Oberli with the epithet, following the form of ending names with a vowel by applying an -i at the end, but also as a modification of latinizing the ending, from oberlius to oberli- + -i, hence oberlii.

From an animal walking along a shore, a potential or actual victim of spinosaur predation — to a fossil fragment of a jaw — to a collector’s trinket in a drawer — to a museum specimen — to a new dsungaripterid taxon being manhandled by apes. The story of a fossil is almost as fascinating as the story of the animal it used to be. But that is not the end of this journey. What comes next is the story of how you, dear reader, come to know of it.

Headden, J. A. & Campos, H. B. N. 2014. An unusual edentulous pterosaur from the Early Cretaceous Romualdo Formation of Brazil. Historical Biology [Published online ahead of print]: 1-13. doi: 10.1080/08912963.2014.904302
Humphries, S., Bonser, R. H. C., Witton, M. P. & Martill, D. M. 2009. Did pterosaurs feed by skimming? Physical modelling and anatomical evaluation of an unusual feeding method. PLoS Biology 5 (8): e204.
Veldmeijer, A. J., Signore, M., Meijer, H. J. M. 2005. Description of two pterosaur (Pterodactyloidea) mandibles from the Lower Cretaceous Santana Formation, Brazil. Deinsea 11: 67-86.

About these ads
This entry was posted in Paleontology, Science Reporting, Taphonomy, Taxonomy and tagged , , , . Bookmark the permalink.

One Response to The Broken Jaw of Banguela

  1. Pingback: An Edentulous Dsungaripterid? 10 Facts About Banguela | The Bite Stuff

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s