Don’t rule out the Pterosaur as King of the Skies Yet

November 21, 2012 at 1:15 pm

Fierce and majestic, the dinosaurs that walked this earth before us star in the dreams of many a child. Perhaps the most majestic of them all, the mighty pterosaur soared above the earth, king of the skies. Recent articles and reports from science writers have tried to burst this dream with the claim that the mighty pterosaur was simply too big to fly, but they may be making their reports too soon. “Science is messy” (Switek) and new papers and claims cannot be held up as scientific fact until they have been adequately supported by other scientists and meaningful evidence. The fact is that this drastic claim that the pterosaur could not fly has not yet reached this threshold of evidence to be considered scientific fact and therefore there is still hope for the pterosaur remaining the king of the skies.

Artist's impression of Quetzalcoatlus. Wikimedia Commons.

Sankar Chattejee, a geoscience researcher at Texas Tech University made the claim that acts as the topic of controversy. According to the research done by Chatterjee, the Pterosaur weighed around 70kg (155 lbs.). 70kg would not allow for enough muscle mass to produce flight for a creature so large, making the pterosaur essentially too weak to fly.

They could have wingspans of up to 10.4 meters, longer than a wingspan of an F-16 Fighter Jet.

Scale of the wingspan of a Quetzalcoatlus, compared with an F-16, a bald eagle and a condor. From Davis, 2012.

Chatterjee’s data and hypothesis did not go uncontested in the scientific community. The biggest point of controversy is the actual weight of the pterosaur. According to Chatterjee, a creature approximately the size of a giraffe with a wingspan of about 35’, larger than an F-16 (Davis), weighs no more than a medium sized human at 70kg. Other researchers argue that the pterosaur weighed closer to 200kg or more. That much weight would allow for enough muscle mass to effective takeoff using the pole vault method that had been widely accepted before this new debate. (See link to video for description of pole vault method). (O’Hanlon)

Another critic, Micheal Habib penned a very convincing counter argument to Chatterjee’s claim.  Micheal Habib who specializes primarily in the anatomy and biomechanics of pterosaurs of the late cretaceous, claims that many of Chatterjee’s hypotheses don’t make anatomical sense. For instance, Habib points out that it simply makes no sense that a flyer would have less wing clearance by jumping for takeoff rather than by running along the ground. “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)” (Habib) Furthermore, Habib points out that while Chatterjee claimed that since the pterosaur cannot operate like scaled up bats, they should work like scaled up birds, but in fact the pterosaurs physiology does not match either the bat or the bird so the point is moot. (Habib)

Clearly there is debate on this topic within the scientific community, so why is there essentially no debate in most science publications? Science writer and paleontologist Brian Switek, one of the leading critics of this new research, believes that the science writing community is too quick to embrace essentially untested research. According to Switek few if any of the new articles in science publications have accounted for or even acknowledged past research done on this topic. “Chatterjee’s presentation is part of a long-running investigation about how pterosaurs took to the air. Ignoring that point, and treating a non-peer-reviewed talk as a new fact to catalog, does a disservice to the science and to readers” (Switek).

Science is, and always has been, an ongoing process of research and revision. Scientific fact cannot just spring forth out of one scientist’s hypotheses. It must first be tested and confirmed by outside sources and evidence. Only then can a theory become a widely accepted fact. It seems that in their search for a sensational story, science writers have forgotten this important law of Science and have attempted to write off pterosaurs as flyers before sufficient proof is established. This debate will likely continue for some time, but until it comes to any definitive conclusion, the pterosaur is still the lord of the skies, no matter what journalists may report.

 

Works Cited

 

By zach | Posted in Student post | Tagged , , , ,

4 Comments

Harris Gordon posted on November 21, 2012 at 6:25 pm

http://www.youtube.com/watch?v=GCpKp73kJtI

Lorena Barba posted on November 21, 2012 at 6:44 pm

What’s a shark got to do with the pterosaur take-off?

Here is a more related video!
The vampire bat running on a treadmill
http://youtu.be/qWOUZAa5vlQ

Lorena Barba posted on November 26, 2012 at 1:57 pm

Here is a link to Liam’s post. Liam decided to cover the point of view of the “Chatterjee camp”, which argues that the Quetzalcoatlus was a wimpy glider that could not take off:
Scrawny Dino Couldn’t Have Lifted itself From the Ground

Michael Habib posted on November 26, 2012 at 5:16 pm

Very pleased to see your group reading and writing about this debate. By way of a little history on this particular scientific controversy, it really goes back to 2004, when S. Chatterjee and J. Templin published a special volume on pterosaurs that included a hypothesized bipedal takeoff for giant pterosaurs and a maximum mass of 75 kg for Quetzalcoatlus. A number of mistakes in the starting assumptions used for their calculations were detected by a handful of scientists (myself included) starting in 2006, and this culminated in two papers challenging their conclusions in 2008: one by Mark Witton that supplied quantitative evidence for greater mass, and one by myself demonstrating that the bending resistance of the forelimb skeleton was more consistent with a quadrupedal launch. Mark and I teamed up the following year to do a larger, joint project that put the two studies together (along with additional quad launch evidence), and this hit print in PLOS ONE in 2010. We came down pretty hard on Chatterjee and Templin in that paper, and their latest offering appears largely to be a reply to that study.

Mark’s Mass paper is free here: http://www.markwitton.com/download/i/mark_dl/u/4009119796/4549073105/Witton%202008%20-%20Pterosaur%20mass%20estimation%20and%20flight.pdf

My quad launch paper is free here: http://epub.ub.uni-muenchen.de/12011/1/zitteliana_2008_b28_09.pdf

Our joint paper is here: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0013982

It should be noted that the reason Chatterjee et al. assert a 75 kg mass is not because of a careful reconstruction from volume or outer dimensions, but instead because they assert that the upper limit for flight in birds (estimated to be about 75-80 kg) must be the upper limit for all flying animals. They appear to be the only group that asserts this; all other animal flight workers, to the best of my knowledge, expect the upper size limits of animal flight to be shape dependent. So far as I am aware, they are also the only group still pushing for bipedal takeoff in pterosaurs.

I’m more than happy to field any questions. Cheers everyone!