Big Pterosaurs Really Did Fly: Interview with Mark Witton

Pterosaurs - winged denizens of the Mesozoic skies - get a bum rap. It's bad enough that their name is smeared by the general public, when animals like Pterodactylus are confused with dinosaurs in the news media and in just about every cheap set of plastic dinosaurs. Lately, some scientists have suggested that the largest of these animals just couldn't fly. Is it true that Quetzalcoatlus (pictured here; image from Wikimedia Commons), with its 10 meter wingspan, had wings that were too narrow, a body that was too portly, and bones that were too weak to support flight? Some of the most recent studies have certainly suggested this!

Yet, extraordinary claims require extraordinary evidence, or at least extraordinary scrutiny. Thus, a study by pterosaur experts Mark Witton and Mike Habib takes a close look at the idea of super-lame flightless giant pterosaurs. Using new body mass estimates, revised reconstructions of the wing dimensions, bone strength calculations, and many other lines of evidence, Mark and Mike argue that even the biggest Quetzalcoatlus could fly after all.

This paper, published in PLoS ONE [full disclosure: I am an editor for this journal], has been featured all over the mainstream news media and blogosphere. For a slightly different take on the matter, I decided to go straight to the source. Mark Witton (pictured below; thanks to Mark for the picture, copyright him) was kind enough to answer a few questions about the study - not just on its methods, results, and conclusions, but also on some of the behind-the-scenes doings that led up to this work.

I've split this interview into two parts. For starters, we'll talk about the genesis of the paper, and some of its major findings.

How did this study come about? Did any particular event spur you and Mike [Habib] into working on this issue of flight in giant pterosaurs?
I reckon a paper like ours has been a long time coming, really. There’s been a lot of talk in recent years that pterosaurs may not be what Greg Paul termed ‘ultralight airbeings’, and numerous blogs and internet forums have responded with comments what this may mean for their flight dynamics. It was only a matter of time before the flight of realistically massed pterosaurs was considered in the technical literature (well, beyond saying they couldn’t fly). We were kicked into action, though, when press reports of an abstract presented by Katsufumi Sato et al. were released in April 2009, saying giant pterosaurs couldn’t fly. Keen members of the palaeoblogsphere may remember this ruffled a fair few feathers when it was released, and their paper (Sato et al. 2009) followed shortly to similarly raised-eyebrows. Most folks even vaguely familiar with large pterosaurs were astonished to see them cap flight at such a low size: 41 kg and 5 m wingspans are very middling in the spectrum of pterosaur size (10.5 m spans and 250 kg body masses are considered maximum in our paper). Because plenty of clearly-flight adapted forms got much larger than this, I got to work on a response. Mike and I have fairly regular correspondence and were talking about the project soon after I started, and it wasn’t long before we realised that working together would make the project much stronger.

Plus, I had giant pterosaurs on the brain at that time. I’d just started work on a massive modelling project where I had to build several models of the largest pterosaurs going. The logistics and costs of building a 13 m span pterosaur against a 10 m span animal is quite something, so I figured a little checking of the wingspans of these poorly known animals wasn’t the worst way to spend an afternoon as it would avoid having to find a bigger workshop. The timing of this was spot on for the project with Mike, too, as it meant we could ensure the size estimates for our flight analysis were as accurate as we could make them. These two events combined to form the beginnings of the paper and reminds me that we started it well over a year ago: where did that time go?

What was the most surprising finding to you, and why?
The most surprising? Hard to put my finger on one thing exactly: we covered quite a lot of topics, and each had their own intriguing little revelations. I mean, the 13 m span estimates of Arambourgiania, the giant pterosaur from Jordan, always seemed a little iffy to me because they were based on a single neck vertebra, but not Hatzegopteryx. Being based on forearm material, I figured the 12 m span estimate for this critter was a sound bet but, no, the material just seems distorted to appear bigger than it actually is. The numbers generated in the flight analysis for the speed of flying giant pterosaurs were impressive, too. The thought of a giraffe-sized pterosaur pumping its wings to scream overhead at 75 mph is staggering: this is real ‘if I had a time machine…’ stuff.

That said, for all these little surprises, the biggest ones came from the paper’s release and press coverage: I was really blown away to see just how much interest we had. To be honest, we did want to make a splash because, following the Sato et al. abstract, the internet is awash with articles saying giant pterosaurs couldn’t fly. We wanted to balance it out a little (this is also, incidentally, why we chose PLoS ONE as our venue: we want interested people of all backgrounds to be able to see our rationale for flighted giants: open access is definitely the way forward, folks). However, I was truly taken aback when our work was quoted directly alongside some half-naked chick in the British tabloids newspaper, The Sun. How often do science stories penetrate that far into the press, let alone those dealing with relatively unimportant extinct flying reptiles? I can only assume that pterosaurs are becoming more exciting and cool with every new discovery, or it was a slow news day. Either way, I’ve not stopped telling people about that since.

Next Time. . .the ins and outs of trans-Atlantic collaborations, and what the media should have mentioned.

Citations
Sato, K., Sakamoto, K., Watanuki, Y., Takahashi, A., Katsumata, N., Bost, C., & Weimerskirch, H. 2009. Scaling of soaring seabirds and implications for flight abilities of giant pterosaurs. PLoS ONE, 4 (4), DOI: 10.1371/journal.pone.0005400.
Witton, M., & Habib, M. (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 (11) DOI: 10.1371/journal.pone.0013982