Today on the Musings we welcome Paul Barrett to talk about the distributions of pterosaurs in time and space – just when and where are all (yes, *all*) the world’s the pterosaur fossils from? This kind of huge data gathering paper is of immense value to research and this will, I have no doubt, result in masses of new research and renewed interest of pterosaurs (assuming the interest has not already been renewed enough already).
For those of you that are inveterate insomniacs, I have finally found a sure-fire cure. It comes in the form of a comprehensive list of pterosaur occurrences on a formation-by-formation basis and forms my contribution (along with my long-suffering co-authors) to the Wellnhofer festschrift. You may be surprised by this rather damning description of my own paper, but let’s be honest, a list is a list and such compilations are never going to be enthralling reading (indeed, I would have severe doubts regarding the sanity of anyone who actually tried to read this cover-to-cover in a single sitting). However, what I think is potentially very exciting about this contribution is that we hope it will form a sound basis for future on the pterosaur fossil record, including macroevolutionary analyses of biogeographic history and diversity through time. Let me explain further.
Assessing the evolutionary history of a clade not only involves investigations into phylogeny and palaeobiology, but also requires appreciation of how the group was distributed in time and space and the relative fortunes of the group through time (i.e. were they diversifying or becoming extinct? If so, why?). The starting points for such analyses are generally compilations such as ours, which provide a summary of the available global literature on pterosaur occurrences and can therefore be used to quickly generate plots of the numbers of pterosaur species through time and to gain an idea of where these beasties lived and where they were most speciose. Publication of the distribution chapters in The Dinosauria (both editions: Weishampel, 1990; Weishampel et al., 2004), which were the models for our paper, sparked a number of projects to look at dinosaur macroevolution that would otherwise have required many hours of library time for any individual researcher interested in addressing these questions. In particular, the information in The Dinosauria led to benchmark analyses if dinosaur diversity and biogeography (e.g. Upchurch et al., 2002; Fastovsky et al., 2004; Wang and Dodson, 2006; Lloyd et al., 2008 and many other studies both published and in preparation). We hope that by providing a similar resource for pterosaur workers these kinds of issues can also be investigated: only a handful of studies on pterosaurs have even begun to explore these questions to date.
Indeed, we have already taken the next step in this process by using our database to investigate what effect (if any) the rock record had on pterosaur diversity, but using the number of pterosaur-bearing formations as a proxy for the amount of available rock through the Mesozoic. Although attendees at last year’s SVP will know what our conclusions are, you’ll have to wait for the full treatment in our forthcoming paper on this topic (Butler et al., in press). We hope this is only the first such use of our pterosaur occurrence data.
As with all such compilations (The Dinosauria equivalents being a good case in point), they start to age even while they are in press, due to the discovery of new material and the reappraisal of existing specimens in museum collections (and the fact we may have inadvertently missed some records, quite likely given the large number of pterosaur papers and their scattered distribution through the specialist literature). Over the next few months, Richard Butler and I are planning to enter our existing data into the Paleobiology Database (PBDB) to make it more widely accessible to other researchers and we hope to correct any errors and deal with any omissions from our database to make it as accurate as possible. So, this message comes with a plea to let us know of any errors you find in the compilation and any omissions: this will allow us to get the PBDB entries right the first time. We also plan to add information on individual pterosaur collections, again as a proxy for the rock record, to further investigate the influence of this record on what we know of pterosaur evolutionary history.
So, although our paper will never any literary awards we hope that the pterosaur community finds it a useful resource and that it will stimulate more work on pterosaur macroevolution than has been attempted before.
Butler, R. J., Barrett, P. M., Nowbath, S. & Upchurch, P. In press. Estimating the effects of the rock record on pterosaur diversity patterns: implications for hypotheses of bird/pterosaur competitive replacement. Paleobiology.
Lloyd, G. T., Davis, K. E., Pisani, D., Tarver, J. E., Ruta, M., Sakamoto, M., Hone, D. W. E., Jennings, R. & Benton, M. J. 2008. Dinosaurs and the Cretaceous Terrestrial Revolution. Proceedings of the Royal Society of London, Series B 275: 24832490.
Upchurch, P., Hunn, C. A. & Norman, D. B. 2002. An analysis of dinosaurian biogeography: evidence for the existence of vicariance and dispersal patterns caused by geological events. Proceedings of the Royal Society of London, Series B 269: 613-621.
Wang, S. C. & Dodson, P. 2006. Estimating the diversity of dinosaurs. Proceedings of the National Academy of Sciences of the United States of America 103:1360113605.
Weishampel, D. B. 1990. Dinosaurian distribution. Pp. 63-139 in D. B. Weishampel, P. Dodson and H. Osmólska, eds. The Dinosauria, First Edition. University of California Press, Berkeley.
Weishampel, D. B., P. M. Barrett, R. A. Coria, J. Le Loeuff, X. Xu, X. Zhao, A. Sahni, E. M. P. Gomani, and C. R. Noto. 2004. Dinosaur distribution. Pp. 517606 in D. B. Weishampel, P. Dodson and H. Osmólska, eds. The Dinosauria, Second Edition. University of California Press, Berkeley.