Pterosaurs: Natural History, Evolution, Anatomy: out at last

Ornithocheirus and Anhanguera welcome you to Pterosaurs: Natural History, Evolution, Anatomy. Double spread from Witton (2013).

So, a rather unexpected and heavy package arrived in my office this week holding copies of Pterosaurs: Natural History, Evolution, Anatomy. The Tweet on the Street™ is that preorders are already being dispatched. Given that I thought we wouldn't be handling actual copies of this thing until late June, these were pleasant surprises indeed. Slight slop with delivery dates around the world aside, I think it's about time to declare this thing as 'published', which I'm very excited about to say the least. I'm not alone in being happy with this development, however. The first review of Pterosaurs hit the web on Tuesday, courtesy of Brian Switek at Laelaps. I'm happy to report that Pterosaurs emerged rather well from it's first wash:

"Witton’s new tribute to pterosaurs gives these fantastic fossil creatures a much-needed makeover... If you’re truly invested in learning about pterosaurs, Witton’s book is a wealth of information that will be of great use to both specialists and curious general readers."

Nice words indeed, and hopefully a sign that the 2.5 years(!) spent on this project were not wasted. I've been deliberately cagey about many of the details of Pterosaurs. A breakdown of the book chapters was revealed a couple of years back, but many of my favourite bits of the book have been held back so as not to pre-empt it's publication. Now that the book is available, I guess it's time to tell people what to expect and, perhaps more importantly, why you should fork out £19.46 for a copy when you could track down, or may already own, Dave Unwin's (2005) The Pterosaurs From Deep Time or Peter Wellnhofer's (1991) Encyclopaedia of Pterosaurs. 

What is a Pterosaurs?
Pterosaurs is meant to provide an interesting read for researchers and diehard enthusiasts, while still being approachable for those who are yet to really acquaint themselves with flying reptiles. If you're familiar with the Unwin and Wellnhofer books, you know the tone I've aimed for. (Those interested in reading a sample of the text will want to download the first chapter from Princeton University Press, and check out an early draft [essentially unchanged in the published text] of Chapter 17.) Pterosaurs is, of course, more up to date than either of these books. Only seven years passing between this book and the last, but the differences are quite pronounced. Despite both Unwin's and Wellnhofer's books dating very well, whole groups of pterosaurs have been discovered since their publications (e.g. 'boreopterids', chaoyangopterids, wukongopterids, and many more in the case of Wellnhofer's tome) and ideas of pterosaur lifestyles and habits have changed considerably. It's of small significance in this field of three modern pterosaur books but, by default, Pterosaurs is the most up to date synthesis on these animals currently available.

Thalassodromeus sethi, a pterosaur with a most unfortunate name, showing a baby Brazilian spinosaur that the food chain works both ways. One of my favourite paintings from Witton (2013).

Pterosaurs is meant to combine the best aspects of preceding pterosaur books into one package, putting Unwin's terrific introduction to the group together with Wellnhofer's coverage of all pterosaur species and important fossils. This results in nine chapters covering the broad-strokes of pterosaur research: the history of their discovery, evolutionary origins, osteology, soft-tissues, locomotion (flight and terrestrial locomotion are discussed separately), palaeoecology and extinction. The other 16 chapters focus on specific pterosaur groups, each featuring a history of discovery, distribution maps, overviews of anatomy (including soft-tissues, where known) and discussions of palaeoecology. These latter chapters broadly follow the phylogenetic scheme of Lü et al. (2010) but, because that will not please everyone, alternative taxonomic proposals are mentioned and discussed where relevant (though hopefully not at expense of readability!). Attempts to present different sides to contentious issues are continual throughout the book. As readers will discover, there is still a lot to learn about these animals and it would be foolish to present only a single view as 'right' when pterosaur science continues to evolve and change. The drive to give everyone fair hearing resulted in a reference list of over 500 works and, hopefully, this will make the book a useful starting point for students new to pterosaurs and wanting to hit the primary literature. (Incidentally, Lü Junchang needs to take a bow as probably the most prolific modern pterosaur worker, his portion of the citation list dwarfing virtually everyone else's despite only beginning in the mid-nineties. Way to go, JC!)

Shiny new things
Pterosaurs is certainly not just a straight review of pterosaur literature, however. Some aspects of the book present wholly new information and ideas, or provide alternatives to existing hypotheses. This particularly applies to the 'palaeoecology' sections of the later chapters, as pterosaur lifestyles are frequently poorly researched. In the worst cases, no lifestyle hypotheses have ever been proposed or are half-sentence afterthoughts thrown onto the end of descriptive papers, so are of little scientific merit. In such instances, I've inserted my own ideas about what these animals may have done based on their gross anatomy and form (including, as depicted above, the proposal Thalassodromeus was a predator of moderately-sized terrestrial prey, following numerous lines of evidence that it's proposed skim-feeding habits are likely incorrect [see Humphries et al. 2007] and its unusually robust, peculiar skull).

Old vs. New. What did pterosaur ancestors look like? We don't know, but the traditional view of them as generic flying reptiles (left, inspired by Wellnhofer 1991) has to go all the same. Right, a newly imagined pterosaur ancestor inspired by recent work into pterosaur origins, representing the third stage ('HyPtA C') of five proposed stages of pterosaur evolution. Both images from Witton (2013). 

One of the highlights of these 'new proposals', for me at least, is a complete retooling of the 'protopterosaur' idea first proposed by Rupert Wild (1978 and others), and then popularised by Wellnhofer (1991) and Unwin (2005). Because of the ambiguity about pterosaur ancestry, Wild and his followers proposed a fairly-generic, lizard-like animal as a hypothetical pterosaur ancestor (above left), which doesn't really fit with modern notions of pterosaur evolution. Although there is still some mileage left in the controversy over pterosaur origins, the idea that pterosaurs were close relatives of dinosaurs is the current hypothesis to beat and, with that in mind, I reworked the likely form of their hypothetical ancestor. Indeed, I tried to imagine a whole series of ancestral species, the 'HyPtAs' (Hypothetical Pterosaur Ancestors), and descibe how they may have developed from a small, sprightly terrestrial reptile to the first actively flying vertebrate. The animal shown at right, above, is a 'stage C' HyPtA, 3 of 5 in this sequence.

More than just words
Part of the reason this book took 2.5 years to put together was because of the amount of new illustrations it warranted. The vast majority of diagrams and graphics - ranging from labelled anatomies (below), skeletal reconstructions, myologies for all major body parts and others - are new, but the book is also well stocked with photographs taken by myself and some very generous colleagues. Of course, the book also features a high number of life restorations of many pterosaur species, sometimes set in backgrounds (as per the painting of Thalassodromeus, above) or in more informative lateral views. Most of these were produced specifically for the book, so most should be new to readers. It's hoped that the abundance of skeletal diagrams and muscle reconstructions should be helpful to artists, and, indeed, some bits of text and imagery are almost provided with artists in mind (Fig. 7.6 may be particularly helpful). The paintings of this book could easily have dissolved into a series of images of pterosaurs flying, but efforts were made to render pterosaurs in never-seen-before guises. There's a bunch of Pteranodon diving several metres into water, Lacusovagus performing a mating dance, an azhdarchid struggling against the 'nuclear winter' of the K/T exinction, Dsungaripterus fighting with one another, and a couple of species just sitting the hell down (quite unintentionally, there's a spirit of All Yesterdays running through a lot of the paintings). The intention was to capture some of the possible diversity in landscape, habits and scale represented by these animals and represent them not just as scientific concepts, but as genuine individuals of real, once-existent species

What fossils reveal about pterosaur wings. Note the differences in wing construction in non-pterodactyloids (left) and pterodactyloids. One of the most informative and detailed diagrams in Witton (2013).

And if I say much more, you won't need to buy it
So that's what to expect from Pterosaurs then, folks, available now in hardback and Kindle editions. I'm very pleased to hear from social media and elsewhere that numerous friends have copies already on order, and hope that you enjoy reading it once it arrives. This message particularly extends to those who've supported the project since I announced it back in August 2010. It was certainly a lot of fun, and very educational putting it together, and I look forward to hearing what everyone thinks once they see it.

References

• Humphries, S., Bonser, R. H., Witton, M. P. and Martill, D. M. 2007. Did pterosaurs feed by skimming? Physical modelling and anatomical evaluation of an unusual feeding method. PLoS biology, 5, e204.
• Lü, J., Unwin, D. M., Jin, X., Liu, Y. and Ji, Q. 2010. Evidence for modular evolution in a long-tailed pterosaur with a pterodactyloid skull. Proceedings of the Royal Society B: Biological Sciences, 277, 383-389.
• Unwin, D. M. 2005. The Pterosaurs from Deep Time. Pi Press, New York, 347 pp.
• Wellnhofer, P. 1991. The Illustrated Encyclopaedia of Pterosaurs. Salamander Books Ltd., London. 192 pp.
• Wild, R. 1978. Die Flugsaurier (Reptilia, Pterosauria) aus der Oberen Trias von Cene bei Bergamo, Italien. Bolletino della Societa Paleontologica Italiana, 17, 176-256.
• Witton, M. P. 2013. Pterosaurs: Natural History, Evolution, Anatomy. Princeton University Press.

Ornithocheirus and Anhanguera: 4 m wingspans are rubbish

It's been a bit pterosaur-light around these parts since I opened the blog in November, with dinosaurs dominating most posts. This week, to start setting things right, we're returning to the warm, leathery-winged bosom of pterosaurs, with a painting from 2010 showing two of the most famous ornithocheirid pterosaurs, Anhanguera santanae (on the left) and Ornithocheirus mesembrinus (right). These Brazilian pterosaurs are both from the Lower Cretaceous Santana Formation, a fossil site renowned for its excellent, three-dimensionally preserved vertebrate fossils. Pterosaurs are the most common tetrapods in this unit, and ornithocheirids are a well known component of that fauna. In fact, they're probably the most extensively documented pterosaurs from the Santana, in part because of the thorough and beautifully illustrated descriptions by Peter Wellnhofer, including those for specimens of Ornithocheirus and Anhanguera (Wellnhofer 1987; 1991). 

Cock of the slight awkward walk: Ornithocheirus. mesembrinus out for a  stroll, possibly trying to accentuate it's bottom. Perhaps it works out. 

Ornithocheirids are unusually proportioned pterosaurs, bearing extremely robust and long wings, enormous heads but tiny bodies and legs. Only other ornithocheiroids, particularly members of Pteranodontia and (to a lesser extent) Istiodactylidae can boast similar proportions. These forms are considered closely related by some (e.g. Unwin 2003), suggesting that their unusual bauplan developed only once, and was taken to extremes by members of Ornithocheiridae and Pteranodontia. In all likelihood, this evolutionary emphasis on increasing the size of the wings and head reflects adaptations for long soaring flight over seas and oceans, while retaining long jaws to grab pelagic prey. This group of ocean-soaring pterosaurs also includes Nyctosaurus, which may be one of the most effective soaring animals to have ever lived. Nyctosaurus also achieves the accolade of being the cover star of my book, which I'm sure it would be much more excited about. 

Two cowardly Anhanguera santanae, being cowardly.

 The painting here shows a few ornithocheirids striding around, an activity that probably wasn't their favourite pastime. Their short trunk skeletons and hindlimbs make for very disproportionate frames, and their forelimbs are probably at the limit of being useful in terrestrial locomotion, beyond simply preventing them from falling over. The pair of Anhanguera on the left are clearly somewhat wary of the larger Ornithocheirus, but it's worth mentioning that they're hardly small. The wingspan of A. santanae is estimated at 4.15 m, which is fairly middling for a Cretaceous pterosaur, but dwarfs the largest flying animals we have today with their piddling 3 m wingspans. Ornithocheirus mesembrinus, by contrast, is one of the largest ornithocheiroids known with an estimated wingspan of 6 m (this, of course, contradicts what Kenneth Branagh told us in Walking with Dinosaurs, but evidence for Ornithocheirus, or any ornithocheirid for that matter, spanning 10 m has yet to be presented). The only ornithocheirid that may have intimidated O. mesembrinus was Coloborhynchus capito, which may have spanned up to 7.25 m (Martill and Unwin 2012), gigantic proportions comparable to those of the largest Pteranodon. Accordingly, when Ornithocheirus wanted to walk or fly somewhere, Anhanguera moved out of its way. 

And that will have to do today, I'm afraid. I've already gone on too long, and I'm much too busy to say anything about other things that are relevant here: colour choices, ornithocheirid rostral structure, ornithocheirid taxonomy and many other things. Perhaps another time, then. 

References

• Martill, D. M. and Unwin, D. M. 2012. The world’s largest toothed pterosaur, NHMUK R481, an incomplete rostrum of Coloborhynchus capito (Seeley, 1870) from the Cambridge Greensand of England. Cretaceous Research. 
• Wellnhofer, P. 1987. New crested pterosaurs from the Lower Cretaceous of Brazil. Mitteilungen der Bayerischen Staatsammlung für Paläontologie und Historische Geologie, 27, 175-186.
• Wellnhofer, P. 1991. Weitere pterosaurierfunde aus der Santana-Formation (Apt) der Chapada do Araripe, Brasilien (Translated title: Additional pterosaur remains from the Santana Formation (Aptian) of the Chapada do Araripe, Brazil).  Palaeontographica Abt. A, 215, 43-101.