ADVERTISEMENT
  About the SA Blog Network













Tetrapod Zoology

Tetrapod Zoology


Amphibians, reptiles, birds and mammals - living and extinct
Tetrapod Zoology Home

Mark Witton’s Pterosaurs: beautiful, lavish, scholarly and comprehensive

The views expressed are those of the author and are not necessarily those of Scientific American.


Email   PrintPrint



Front cover of Witton (2013): an antlered nyctosaurid at sunset.

I assume you’re here for the Tetrapod Zoology. If so, you’ll have been excited and intrigued by one of 2013’s best tetrapod-themed books: Mark Witton’s Pterosaurs, an enormous, lavishly illustrated encyclopedia of all things pterosaur. Scholarly but highly readable, fully referenced throughout, and featuring hundreds of excellent photos, diagrams and beautiful, colour life restorations, this volume is a must-own, whatever your interest in pterosaurs. And, let’s face it, there aren’t that many books devoted to pterosaurs to begin with, so another one on the market can only be a good thing.

Herein, please find my assorted thoughts on this most excellent book. First of all, though, some disclosure: as readers and followers will likely already know, I’m personal friends with Mark and have co-authored several studies with him. You might therefore conclude that the following review is not impartial; nevertheless, let’s see what happens. For the purposes of convention, I’m going to refer to Mark as ‘Witton’ throughout this review.

I already gave a summarised version of my general thoughts on the volume back in June 2013. Here’s the most important part of what I said: “[Pterosaurs is] written as an encyclopaedic tour through pterosaur diversity. This really is the ultimate guide to pterosaurs, providing us with a richer view of pterosaur diversity and behaviour than allowed in the two previous great volumes on the group (Wellnhofer 1991, Unwin 2005) and containing a substantial amount of review and analysis of pterosaur ecology and functional morphology”. I was surprised (but pleased) to see these words quoted on a flyer that Princeton University Press provided in the delegate package for the 2013 Society of Vertebrate Paleontology meeting. I should also say that the book is properly titled Pterosaurs: Natural History, Evolution, Anatomy. However, this title doesn’t appear anywhere on the cover (or spine).

"No one messes with the 6-m wingspan Ornithocheirus, not even two 4-m wingspan Anhanguera shown on the left of this image". This image appears in the ornithocheirid chapter and also - as here - as the opener to the book. Image by Mark Witton, from the MarkWitton.com blog.

To business… Pterosaurs is a big book, featuring 26 chapters spread over more then 280 pages. Early chapters review the history of our ideas about pterosaurs, the evolutionary relationships and origin of the group, and what we know of their anatomy (bony and soft).

Pterosaur ancestry and those hypothetical proto-pterosaurs

Canyon-dwelling proto-pterosaurs (specifically, this is HyPtA D, donchaknow). Image by Mark Witton.

Many issues covered here remain controversial: the consensus opinion supported by the majority of recent phylogenetic studies is that pterosaurs are crown-archosaurs, close to dinosaurs (remember, Ornithodira exists no matter where pterosaurs fall within Diapsida) (Sereno 1991, Benton 1999, Brusatte et al. 2010, Nesbitt 2011). This is the idea that Witton favours, which is fair enough since there are unpublished studies* showing that the crown-archosaur hypothesis is supported even when oddball taxa considered close to pterosaurs by some (Peters 2000) are included in the analysis too. Nevertheless, the crown-archosaur idea does look odd given that we lack taxa that appear in any way transitional between pterosaurs and other ornithodirans**… not that I’m saying that this necessarily means anything.

* I’m thinking of analyses run by Mickey Mortimer and Andrea Cau.

** Faxinalipterus minima – published in 2010 as a possible sister-taxon to the rest of Pterosauria – is not a pterosaur, nor obviously close to pterosaurs at all (Soares et al. 2013).

Witton follows the honourable tradition of inventing hypothetical proto-pterosaurs that bridge the gap between Scleromochlus-like ornithodirans and known, early pterosaurs. I’m not entirely sold on his use of the term HyPtA (meaning Hypothetical Pterosaur Ancestor) for these creatures – not exactly sexy – but his invention of the creatures themselves isn’t all that bad: invoking an anatomy and lifestyle for an ancestral organism involves the formulation of a set of hypotheses that will be supported or knocked down by future finds. And there are other proto-pterosaurs out there in the literature, just as there are proto-birds and proto-bats.

Flying, walking, climbing… and running and swimming?

Pterosaurs are lame and clumsy on the ground, you say? Probably not. Dsungaripterids try to get a partial dinosaur carcass from an azhdarchid. Image by Mark Witton.

Chapter 6 – ‘Flying reptiles’ – summarises current thinking on pterosaur aerodynamics and launch behaviour, one of Witton’s most interesting contentions being that pterosaurs have consistently been made too lightweight by previous authors. This has some impact on wing loading and hence flight style: as is familiar to pterosaur workers, Witton’s revised mass estimates and wing loadings make pterosaurs more comparable to the birds that they otherwise resemble in planform (Witton 2008, 2013, Witton & Naish 2008) – a satisfying picture that has been bolstered by conclusions from some other workers (but, of course, not all of them; this is pterosaur science we’re talking about).

Somewhere on a rooftop in London's West End, in the heady Summer of 1998 , a hard-working team of graphic designers are re-enacting the terrestrial gait of the pterosaur Ornithocheirus. Using brooms. And that guy isn't a slave: he's a member of the animating team. Image (c) BBC/Impossible Pictures.

More innovative is Chapter 7 (‘Down from the skies’), devoted to terrestrial locomotion. Witton’s pterosaurs can bound, swim, climb, and most of them walk with narrow gaits (though these generalisations do not apply across the whole of Pterosauria, of course). The pterosaurs of the prior literature have been imagined as inelegant sprawlers, slow, clumsy and lame on the ground, unable even to resist light gusts of wind (recall how the terrestrial locomotion depicted for the Walking With Dinosaurs ornithocheirids was based on shuffling people, using brooms as crutches) (Wellnhofer 1988, Unwin 1988, 1997, 2005).

In fact, data from trackways, pelvic and limb morphology, limb bone thickness and bending strength (Fastnacht 2005), and inferred hindlimb and forelimb posture (Fujiwara & Hutchinson 2012) indicates very strongly that pterodactyloid pterosaurs at least were far more proficient on the ground than people have previously given them credit for. Witton weaves all these lines of evidence together in a compelling narrative and can be said to be leading a revolution on the terrestrial abilities of pterosaurs. I agree with him: it now seems that pterodactyloids were proficient and agile on the ground, though non-pterodactyloids likely were not.

Swimming ornithocheirids, by Mark Witton. It remains controversial whether ornithocheirids could really swim like this.

Readers may also be surprised to see several Witton illustrations that show pterosaurs swimming and even diving. Some trackways seemingly show that some pterosaurs foraged in shallow water, their bodies afloat and their long forelimbs being used as punting tools. Given the aquatic habits of many pterosaur species, it’s hard to believe that they were incapable of at least some aquatic behaviour: despite claims made here and there about pterosaurs being too pneumatic to swim or dive, or with a wing form or body shape that would prevent swimming or diving, there are no obvious or compelling reasons disallowing such behaviour, and Witton proposes that taxa like Pteranodon might routinely have floated and dived.

Yes, there are frigatebirds (which can swim, if they really have to, but generally avoid doing so*), but hardly any pterosaurs are as specialised for a dedicated aerial existence as they are (nyctosaurids are the probable exception). Recently, Hone & Henderson (2013) used digitally simulated floating models to test the floating abilities of pterosaurs. It’s a brilliant and fun thing to do – did I ever mention that it’s been done before for giraffes? (Henderson & Naish 2010). Ha ha, I kid, I kid. Anyway, Hone & Henderson (2013) concluded that pterosaurs were pretty much incapable of floating or swimming. I’m sceptical of their conclusions, but it’s good to see some actual science being applied to this interesting issue.

* They bathe by dunking themselves after swooping at the water from height and take off as soon as possible by frantic fluttering.

Chapter 8 – ‘The private lives of pterosaurs’ – reviews several areas that will be unfamiliar to the majority of non-specialists: what do we know about pterosaur prey items, pathologies, parasites, sex lives and growth strategies? The honest answer is “not much”, ha ha, but we do know enough to at least give us an insight into all of these areas. As is the case throughout the book, diagrams and life reconstructions depict the key evidence or show re-enactments of things that really must have happened.

Pterosaur diversity, group by group

Tet Zoo newbies might not know of the Witton-led pterosaur exhibition of 2010. Follow links below for more. David Attenborough (the one on the left) visited and is here talking to Mark about azhdarchids. Photo by Lauren Pearce.

The meat and proverbial potatoes of the book is formed by reviews of all pterosaurian groups. Each group (each ‘family’, if you like) gets its own chapter. Once upon a time, popular books would have given you the impression that pterosaur diversity consisted of Dimorphodon, Rhamphorhynchus, Pterodactylus and Pteranodon and not much else. But things have boomed in recent decades, such that the chapters here on wukongopterids, boreopterids, lonchodectids, chaoyangopterids, thalassodromids and others will be wholly novel to some readers.

On that note… as is well known, views on the phylogeny, systematics and nomenclature of pterosaurs vary quite considerably from one study to the next (though note that members of particular research communities do tend to converge on similar results… read into that what you want). Witton notes this and the arrangement he favours – in general, it’s the phylogenetic scheme recovered by Lü et al. (2010) – is of course not the one favoured by all pterosaur experts. But, come on, when you’re doing a book you have to come up with an arrangement of some sort.

Pterosaurs: far from samey; nuance and variation everywhere you look

The skeletons of select pterodactyloids scaled to the same humerus length: the major variation in proportions should be obvious. Image by Mark Witton, from Witton (2013).

Anyway, each of these chapters introduces us to the group in question, reviews and discusses what we know of its anatomy, discusses the probable flight and grounded, terrestrial behaviour of the group’s members and, finally, provides an overview of palaeoecology. The last thing there – the discussion of palaeoecology – is one of the most novel aspects of the book. Tradition and convention would have it that pterosaurs flew over the surface of the sea and caught fish, or flew close to watery places and caught dragonflies and other flying insects. Admittedly, this ‘samey’ view of pterosaurs was challenged by the idea that dsungaripterids might have eaten shelled molluscs (Wellnhofer 1991) and that tapejarids were perhaps frugivorous (Wellnhofer & Kellner 1991). But, otherwise, the overwhelming impression has always been that pterosaurs caught fish or insects while flying on the wing.

I tried to get on the 'pterosaurs-were-more-diverse-than-convention-would-have-it' bandwagon early on, but fell off. This leaf-eating Tapejara comes from 1991 or thereabouts. Image by Darren Naish.

In fact, details present across the pterosaur skeleton show, Witton (2013) argues, that all those different pterosaur groups were doing different things – sometimes subtly different things, sometimes strikingly different things. As an example, let’s briefly consider the long-snouted, long-winged ornithocheiroid-type pterosaurs (istiodactylids, boreopterids, ornithocheirids, nyctosaurids and pteranodontids), virtually all of which possess proportionally small, relatively weakly muscled hindlimbs. These pterosaurs all look more or less alike, and, yeah, the general view has been that they pretty much all do the same thing… they, you know, flew over the surface of the sea and grabbed fish.

But when all of their anatomical nuances, proportional differences and so on are examined, a case can be made that we are, in fact, seeing groups of species that, even within this one clade, perhaps did such diverse things as scavenge from vertebrate carcasses in terrestrial environments, grab fish from the sea surface, float or swim and ‘cage’ mouthfuls of small, planktonic prey, float and made short surface dives, and live a frigatebird-like life (Witton 2013).

One of the most dynamic images in the book: Thalassodromeus portrayed as a hefty badass that can hunt and kill small dinosaurs (like the juvenile spinosaurid shown here). Image by Mark Witton, from the MarkWitton.com blog.

In short, Witton’s view of pterosaurs is exciting and refreshing in its diversity, complexity and plausibility. Think of modern animal groups, whether they be gulls, seals or anoles: anatomical differences reflect different feeding and foraging strategies, nuances and niche-specific behaviours are everywhere, and no two species are ever really alike. This sort of thing was surely true of extinct animals – I’m sure it was, we all are. But this is about the first time that we’ve seen this many ideas on pterosaur behaviour and lifestyle.

I personally think that more ideas of this sort are needed – so long as, that is, that they are internally logical, look at data from all available lines of evidence, and appear grounded in a good understanding of biomechanics, ecology, and the anatomy, behaviour, diversity and functional morphology of living animals. As should be obvious from the fact that I co-author with him (Witton & Naish 2008, 2013), I think that Mark is very good at this sort of thing (certainly better than those palaeontologists who take just one or two features and concoct an unrealistic and unlikely behavioural hypothesis) and I generally find myself agreeing with his conclusions and hypotheses.

However, it’s important to note that, at the moment, many of the ideas that Witton discusses and explores are, indeed, just ideas: typically proposed here for the first time ever, they now require investigation using rigorous, quantitative techniques. But, hey, you have to start somewhere. Mark knows this and his hypotheses should serve as an inspiration for future studies.

Standardised reconstructions like these (these show the azhdarchoid Tupuxuara leonardii) feature throughout the book. Image by Mark Witton, from the MarkWitton.com blog.

If there’s anything that becomes a takehome with regard to this book, it’s that pterosaurs are more diverse in anatomy and proportions than has been made obvious before. Without naming names, the general impression created by some pterosaur workers is that pterosaurs are basically all alike, only with different skulls. As is made clear, not only through the text, but also thanks to those standardised reconstructions, pterosaurs actually exhibit notable and significant differences in the length and form of the neck, in wing length, in hindlimb size, and in… well, in everything, really.

Some underappreciated diversity

Awesome depiction of the Triassic weirdass pterosaur Caviramus (= Raetiodactylus) sheltering in a cave. I have a horrible feeling that I'm showing all the best images from the book in this article. Not my fault: I'm only using what's already online. Image by Mark Witton.

Let’s look at just a few examples of this underappreciated diversity. Among the weirdest of pterosaurs are the campylognathoidoids*. Check out some of the strangeness in these animals. Campylognathoides has absurdly robust humeri that make it look “like a little pterosaurian gorilla” (Witton 2013,p. 119) as well as ridiculously elongate wing-fingers. Meanwhile, Caviramus (taken by Witton to include Raeticodactylus and remarkable for its bony nasal horn) has incredibly long, slender humeri nearly 20 times longer than they are wide at mid-shaft. Clearly, these weird early pterosaurs were doing something unusual – as usual, the question is: what?

* As per my comment above about disparate views on phylogeny, not all workers recognise this group as a clade. Witton describes the possible artificiality of his grouping together of the constituent taxa. Again, if you’re covering animals on a group-by-group basis, what you gonna do? A degree of paraphyly and non-monophyly has to be tolerated (yeah, paraphrasing McKenna and Bell there).

As you’ll know from the reconstructions you’ve seen of long-tailed pterosaurs like Rhamphorhynchus, some (or all?) long-tailed pterosaurs possess soft-tissue vanes at the tips of their tails. And, thanks to Rhamphorhynchus, everybody knows that this vane was diamond-shaped or subtriangular (its form seemingly changing during ontogeny (Bennett 1995)). Right? Well, Rhamphorhynchus isn’t the only pterosaur where the soft-tissue structures on the tail are actually preserved, and those structures known for other taxa are markedly different. Little Sordes from Kazakhstan has a long, lobed structures shaped like a long, narrow leaf – perhaps all of its close relatives did too – while Pterorhynchus has a series of paired serrations that run along the sides of the end half of its tail.

We need more books like this

Pterosaurs lived, and pterosaurs died. A small azhdarchid moves in to claim temporary ownership of a carcass of one of its larger brethren, maniraptorans move aside. Image by Mark Witton.

The pace of pterosaur research means that, needless to say, many new things have appeared since Pterosaurs appeared. There are quite a few new, recently named taxa that would have warranted discussion or mention including the Tupuxuara-like azhdarchoid Caupedactylus, the small azhdarchoid Vectidraco, the Patagonian azhdarchid Aerotitan, and a raft of new Cambridge Greensand taxa. Witton’s scepticism about the alleged azhdarchoid identity of Aurorazhdarcho (he has it wrongly spelt Auroazhdarcho [sic]) has since been confirmed by Bennett’s (2013) paper on Pterodactylus and Ardeadactylus, and then there’s the whole awkward situation involving Lonchodraco and Lonchodraconidae. New studies on pterodactyloid limb posture have appeared (Fujiwara & Hutchinson 2012, Costa et al. 2013), and so on and on.

Overall, the style of the text is friendly and conversational, even witty and vernacular. There are definitely places where I feel that it needed to be a bit tighter, and I get the impression that better copy-editing was needed. On other negative points, one or two of the illustrations look a bit rushed (I don’t much like the theropod on p. 102) and I’m not sure that the curly lines used in a few of the diagrams (e.g., Figs 7.8 and 9.2) – they look like something out of a Tim Burton movie – fit with the rest of the book. However, these are exceptions in an otherwise glorious tour-de-force.

Aren't we all waiting for some other grand, lavishly illustrated pterosaur volume? Sigh.

As if it’s not clear enough from what I’ve already said, Witton’s Pterosaurs is a remarkable visual feast, packed full of novel art as well as excellent photographs that he clearly worked hard to obtain. There are, in fact, illustrations of some sort on virtually every single page – you will never get bored of looking at this book. A major Wittonian innovation is the invention of a consistent pose for pterosaurian reconstructions (both skeletons and life restorations). Reminiscent of Greg Paul’s lateral-view dinosaurs, they make it easy to compare and contrast the many taxa Witton illustrates. And look out for the nods and witty homages: without giving the game away, there are references here to Batman Begins, the arthropod-filled gorges of Skull Island… and what, exactly, is that marking on the lonchodectid’s wing?

If you like or are even vaguely interested in pterosaurs, or, hell, are interested in tetrapod evolution, diversity or history in general, you really need to see this book. I dearly hope that it inspires others to produce similar, spectacularly well-illustrated volumes on other tetrapod groups. The world would be a better place for it.

Witton, M. P. 2013. Pterosaurs. Princeton University Press, Princeton and Oxford. Hardback, pp. 291, $35.00 / £24.95, ISBN 978-0-691-15061-1. Buy it here. A kindle version is available here. A sample of text is available here. Mark’s blog (technically, the MarkWitton.com Blog) is here and his website is here.

For previous Tet Zoo articles on pterosaurs, see…

Refs – -

Bennett, S. C. 1995. A statistical study of Rhamphorhynchus from the Solnhofen Limestone of Germany: year-classes of a single large species. Journal of Paleontology 69, 569-580.

- . 2013. New information on body size and cranial display structures of Pterodactylus antiquus, with a revision of the genus. Paläontologische Zeitschrift 87, 269-289.

Benton, M. J. 1999. Scleromochlus taylori and the origin of dinosaurs and pterosaurs. Proceedings of the Royal Society of London B 354, 1423-1446.

Brusatte, S. L., Benton, M. J., Desojo, J. B. & Langer, M. C. 2010. The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida). Journal of Systematic Palaeontology 8, 3-47.

Costa, F. R., Rocha-Barbosa, O. & Kellner, A. W. A. 2013. A biomechanical approach on the optimal stance of Anhanguera piscator (Pterodactyloidea) and its implications for pterosaur gait on land. Historical Biology doi: http://dx.doi.org/10.1080/08912963.2013.807253

Fastnacht, M. 2005. The first dsungaripterid pterosaur from the Kimmeridgian of Germany and the biomechanics of pterosaur long bones. Acta Palaeontologica Polonica 50, 273-288.

Fujiwara, S.-i. & Hutchinson, J. R. 2012. Elbow joint adductor moment arm as an indicator of forelimb posture in extinct quadrupedal tetrapods. Proceedings of the Royal Society of London B 279, 2561-2570.

Henderson, D. M. & Naish, D. 2010. Predicting the buoyancy, equilibrium and potential swimming ability of giraffes by computational analysis. Journal of Theoretical Biology 265, 151-159.

Hone, D. W. E. & Henderson, D. M. 2013. The posture of floating pterosaurs: ecological implications for inhabiting marine and freshwater habitats. Palaeogeography, Palaeoclimatology, Palaeoecology doi: 10.1016/j.palaeo.2013.11.022

Lü, J., Unwin, D. M., Jin, X., Liu, Y. & Ji, Q. 2010. Evidence for modular evolution in a long-tailed pterosaur with a pterodactyloid skull. Proceedings of the Royal Society B 277, 383-389.

Nesbitt, S. J. 2011. The early evolution of archosaurs: relationships and the origin of major clades. Bulletin of theAmerican Museum of Natural History 352, 1-292.

Peters, D. 2000. A reexamination of four prolacertiforms with implications for pterosaur phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106, 293-336.

Sereno, P. C. 1991. Basal archosaurs: phylogenetic relationships and functional implications. Society of Vertebrate Paleontology Memoir 2, 1-53.

Soares, M. B., Dalla Vecchia, F. M., Schultz, C. L. & Kellner, A. W. A. 2013. On the supposed pterosaurian nature of Faxinalipterus minima Bonaparte et al. (2010) from the Upper Triassic of Rio Grande do Sul, Brazil. In Sayão, J. M., Costa, F. R., Bantim, R. A. M. & Kellner, A. W. A. (eds) International Symposium on Pterosaurs, Rio Ptero 2013, Short Communications. Universidad Federal do Rio de Janeiro: pp. 95-97.

Unwin, D. M. 1988. New remains of the pterosaur Dimorphodon (Pterosauria: Rhamphorhynchoidea) and the terrestrial ability of early pterosaurs. Modern Geology 13, 57-68.

- . 1997. Pterosaur tracks and the terrestrial ability of pterosaurs. Lethaia 29, 373-386.

- . 2005. The Pterosaurs From Deep Time. Pi Press, New York.

Wellnhofer, P. 1988. Terrestrial locomotion in pterosaurs. Historical Biology 1, 3-16.

- . 1991. The Illustrated Encyclopedia of Pterosaurs. Salamander Books Ltd, London.

- . & Kellner, A. W. A. 1991. The skull of Tapejara wellnhoferi Kellner (Reptilia, Pterosauria) from the Lower Cretaceous Santana Formation of the Araripe Basin, northeastern Brazil. Mitteilungen der Bayerischen Staatssammlung für Paläontologie und Historische Geologie 31, 89-106.

Witton, M. P. 2008. A new approach to determining pterosaur body mass and its implications for pterosaur flight. Zitteliana B28, 143-158.

- . 2013. Pterosaurs. Princeton University Press, Princeton & London.

- . & Naish, D. 2008. A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLoS ONE 3: e2271.

- . & Naish, D. 2013. Azhdarchid pterosaurs: water-trawling pelican mimics or “terrestrial stalkers”? Acta Palaeontologica Polonica doi: http://dx.doi.org/10.4202/app.00005.2013

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.





Rights & Permissions

Comments 77 Comments

Add Comment
  1. 1. GaffaMondo 7:31 am 12/27/2013

    I may need a second copy of this book so that I have one to keep and read, and one to chop and stick all over the walls for reference. Really, really nice book. And Mark’s sense of humour is an added bonus.

    Link to this
  2. 2. AndreaCau 8:44 am 12/27/2013

    “remember, Ornithodira exists no matter where pterosaurs fall within Diapsida”.
    True, although I might find quite confusing to call crocodiles (or event lizards, according to some very very very unplausible positions) as “bird-necked” if pterosaurs result outside Archosauria.
    I suggest a re-definition of Orhithodira that explicitly excludes crocodilians and other non-avian extant reptiles.
    I think it would be good to restrict the Ornitho/Avi-names to stems anchored to birds and excluding extant non-avian reptiles.

    Link to this
  3. 3. SciaticPain 12:00 pm 12/27/2013

    Excellent book and agree with all points- would love to see comprehensive illustrated volumes on say mosasaurs or fossil crocs.

    On the question of pterosaur diversity: as the book portrays we now know pterosaurs were doing a wide variety of things anatomically/behaviorally/ecologically over the Mesozoic. But for me the question remains- why don’t we see high pterosaur diversity sustained throughout the whole of the Mesozoic? are we simply missing huge chunks of data from lack of lagerstaten? Take for instance Istiodactylids, huge dino carcasses should have made this family of pterosaurs, or pterosaurs like them, ubiquitous throughout the Mesozoic, but so far they appear limited in time and scope. Same for anurognathids, with no bats or hawking aerial birds during the Mesozoic they should have been spectacularly abundant/diverse. But even when you account for the low fossilization potential for these little guys they are only known from a couple species across the whole of the Mesozoic? And why do azhdarchid pterosaurs, the largest and possibly most terrestrial pterosaurs, dominate pterosaur diversity in the late Cretaceous?

    I have heard it mentioned before that changing oxygen levels may be related to the waxing and waning of pterosaur diversity. Would love to hear any thoughts on the idea of thinning atmosphere curtailing pterosaur diversity.

    Duane Nash
    antediluvian salad

    Link to this
  4. 4. Biology in Motion 12:38 pm 12/27/2013

    SciaticPain: your first guess is the best supported at present – namely, that we are lacking huge chunks of data for pterosaurs throughout much their duration. This paper by Butler et al. looks at that very question: http://paleobiol.geoscienceworld.org/content/35/3/432.abstract

    Their bottom line is that there is little to no support for a long term decline in pterosaurs once sampling bias is accounted for. There is also no evidence in the corrected datasets for competitive replacement by birds.

    While changing atmospheric conditions can be associated with changes in global diversity, there is no particular reason that it should have had a disproportionate effect on pterosaurs. I think (but I am not sure) that the original argument was tied to the assumption that a thinner atmosphere would cripple flight. However, it would require quite a substantial change in atmospheric density to affect flight dynamics for anything much larger than a small songbird (note that small changes in density/composition *can* greatly impact insects and other small flyers). Geochemical evidence indicates that the Cretaceous atmospheric density was roughly the same as the modern density (which is to be expected).

    Link to this
  5. 5. Mike from Ottawa 1:45 pm 12/27/2013

    I like Gaffamondo’s idea of getting another copy so I can put the pictures up on the wall. My government cubiclicle (as a cubicle is a small cube, so …) walls could use some livening up.

    And, and I don’t think this point was made in the review, the book is amazingly inexpensive. On Amazon Canada, it doesn’t even cost enough to qualify for free shipping. Just a bit over $23. IMO, that represents the highest awesome per dollar of any book I’ve seen.

    It’s a brilliant book and the only major downside for me is it makes me sad there isn’t something like it for marine reptiles or those crazy Mesozoic crocs.

    Link to this
  6. 6. ohnosir 1:56 pm 12/27/2013

    This book looks spectacular, I can’t wait to get a copy! Along with my ever-increasing wishlist of other must-haves…it seems like there has been an explosion of great books lately!

    On a related note – I am a senior working on my BFA, and I have plans to independently publish my own illustrated volume on the Paleogene South American marsupial radiation for my thesis…umm, a big undertaking, for sure, especially since I am not at an institution where I have easy access to the research, and I am not working with a publisher. I was wondering if anybody might advice in this area or point me in the direction of someone who would be open to talk. I am especially keen to learn more about the etiquette of referencing other authors’ research.

    That being said, congratulations to Mark Witton on the publication of this book. It sounds as though this was a much-needed reprise of pterosaur research!

    Link to this
  7. 7. Andreas Johansson 2:13 pm 12/27/2013

    My family inconsiderately didn’t get me this fo Xmas, so I shall have to get a copy for myself.

    (They’re not all bad tho’; they did get me a copy of Loxton and Prothero’s Abominable Science!.)

    Link to this
  8. 8. SciaticPain 5:23 pm 12/27/2013

    @Biology in Motion thanks for information, in regards to big flyers doing better in thin air than smaller flyers that actually makes sense in light of Andean condors and cranes migrating over the Himalayas.

    Link to this
  9. 9. LeeB 1 5:50 pm 12/27/2013

    Yes it would definitely be good to have equivalent volumes on mossasaurs, plesiosaurs and nothosaurs, and ichthyosaurs.

    What would also be interesting would be a guidebook to the pleistocene megafauna worldwide; including both the living megafauna and the species that have gone extinct over the last 50 000 years.
    It would have to cover not only mammals but also birds and reptiles and be completely global in scope, and the coverage would be at the species level.

    Given the numerous pleistocene fossils this is actually possible; and would give people an idea of what the earth was truly like before people got too good at killing things.

    LeeB.

    Link to this
  10. 10. Yodelling Cyclist 6:00 pm 12/27/2013

    @LeeB1: Something tells me that someone is having a determined crack at a book covering the entire chordate fossil record. Assuming said individual doesn’t blow up, go mad, and get found wondering the streets of southern England shrieking “FISH!” at passers by.

    Volumes dedicated to mosasaurs, icthyosaurs and other assorted, relatively obscure mesozoic groups would be wonderful (dinosaurs do tend to hog the limelight in their own inimitable fashion).

    Link to this
  11. 11. LeeB 1 6:52 pm 12/27/2013

    Yes but sometimes it is good to realise that the past is more than the Mesozoic.

    And the current megafauna doesn’t really make sense until you look at prior to the ongoing extinction event.

    A few widespread large mammals is an uncommon state of affairs; large mammals can be widespread but they were far more speciose until recently.

    LeeB.

    Link to this
  12. 12. David Marjanović 8:43 am 12/28/2013

    Faxinalipterus minima

    Of course that’s F. hminimus.

    Again, if you’re covering animals on a group-by-group basis, what you gonna do? A degree of paraphyly and non-monophyly has to be tolerated (yeah, paraphrasing McKenna and Bell there).

    Easy: put them directly under the next higher heading, without putting them in a subchapter.

    Link to this
  13. 13. David Marjanović 8:44 am 12/28/2013

    Stray h detected! Shoot on sight!!!

    Link to this
  14. 14. Dartian 10:51 am 12/28/2013

    Darren:
    Front cover of Witton (2013): an antlered nyctosaurid at sunset.

    Antlers? Assuming that you weren’t speaking tongue-in-cheek, is there any actual precedent in the literature for referring to that kind of cranial outgrowths in non-cervids/non-ruminants as ‘antlers’?

    Link to this
  15. 15. naishd 12:44 pm 12/28/2013

    I’m just using ‘antler’ to mean ‘big pointy branch thing sticking out of animal’s had’. As for non-cervids with ‘antlers’, there are antlered flies (not to be confused with antler flies) and both stagbeetle jaws and notodontid caterpillar horns are sometimes called antlers.

    Link to this
  16. 16. Jenny Islander 1:11 pm 12/28/2013

    Re lack of lagerstaten: If I took a trip to, say, the Lower Cretaceous, would it be plausible for me to see a flock of crow-sized pterosaurs arguing possession of some berry bushes with a flock of crow-sized birds? Or some birds analogous to modern vultures waiting patiently for an early azhdarchid to open a carcass (or vice versa)?

    Also, speaking purely as a dabbler, it seems to me that waterfowl must have been a uniquely avian thing. AFAICT, any flying tetrapod can swim if it has to, if it didn’t land too hard, if nothing eats it, and if it isn’t in the water long enough to become hypothermic or exhausted. But sitting on the water for hours, periodically sticking more of my body into it to get food, sleeping there even, requires, I think, thicker insulation than a little fur–if you want to also fly, anyway. Oiled flat feathers layered over puffy down, with a relatively small amount of fat under the skin (yes, a duck is fatty, but nothing like a seal), would beat pterosaur fur every time–wouldn’t they? Or am I missing something?

    Link to this
  17. 17. Jerzy v. 3.0. 1:24 pm 12/28/2013

    Nice book, congrats to Mark.

    In pterosaur biology, indeed, there is lots of “what-is-not-here-and-should-have-been-is-more-telling-than-what-is”. Why almost no fossils of eggs and neonates? Why whole ecological niches were not occupied?

    Is the situation that pterosaur fossils are relatively scarce, fragmentary and biased towards certain niches, compared to dinosaurs; matched by bird-large mammal fossils? Or something more about it?

    Link to this
  18. 18. Jerzy v. 3.0. 1:26 pm 12/28/2013

    @16
    I think many small pterosaurs had thick insulation of fat and long fur, much like birds and small maniraptorians, and some of Mark’s pictures may be too thin (All Yesterdays style).

    Link to this
  19. 19. Jerzy v. 3.0. 1:32 pm 12/28/2013

    One more question
    Could pretosaur wings have soft-tissue extensions or gaps, and not always go in a relatively straight line between the wingtip and legs/abdomen?

    Link to this
  20. 20. Yodelling Cyclist 2:34 pm 12/28/2013

    I appreciate that I really should buy the book rather than ask questions here: but I’m poor. How much is known about pycnofibre structure? Is it not possible that there was water proof and insulating fluff? How confident can we be that there was no insulating fat layer?

    Is it delusional to suggest that pycnofibres and feathers may be homologous (grief I hope I’ve used the right term – derived from a common ancestor), and how similar (or not!) are they to the filamentous structures reported for ornithiscians?

    Finally, are any polar pterosaurs known?

    Regards, and Happy New Year all.
    Yod

    Link to this
  21. 21. Yodelling Cyclist 3:12 pm 12/28/2013

    @SciaticPain: About the large pterosaurs being most diverse: Cretaceous sea levels were high and large-ish islands presumably common place. Large mammalian terrestrial carnivores struggle to maintain large population sizes if subject severe range restrictions, large mesozoic predators may well have had similar issues. On the other hand, pterosaurs would be able to harvest the resources of many islands to grow to large sizes, permitting them to rock up, physically dominate much of the local fauna and leave at whim. With such large ranges and diverse resources specialisation might be expected. On the other hand of course, their long range would mean that populations would almost never be separated by geographical features – so effectively all speciation would be sympatric which might be a bit of a brake on diversification. I’ve no idea which effect would dominate – it might be analogous to (what I understand of) steamer ducks, in that localised specialist (in the case of the ducks, flightless, but this need not be a necessity for the pterosaurs – “unable to fly across the Atlantic” would have the same effect) pop up while large, flighted, generalist, ancestral species continue to stomp around the globe.

    Link to this
  22. 22. Dartian 2:44 am 12/29/2013

    Darren:
    there are antlered flies (not to be confused with antler flies) and both stagbeetle jaws and notodontid caterpillar horns are sometimes called antlers

    Oh? Those entomologists!

    Jenny:
    lagerstaten

    Lagerstätten (singular: Lagerstätte) – and preferably with a capital L, since the word derives from a German noun.

    sitting on the water for hours, periodically sticking more of my body into it to get food, sleeping there even, requires, I think, thicker insulation than a little fur

    Two words: sea otters. (Of course, to refer to the thick pelage of sea otters as “a little fur” would be somewhat of an understatement.)

    Link to this
  23. 23. Dave Hone 7:22 am 12/29/2013

    I know it’s very much a sideline to the main thrust of the article on Mark’s excellent book, but that statement “Hone & Henderson (2013) concluded that pterosaurs were pretty much incapable of floating or swimming” isn’t really right.

    Of course pterosaurs float very well, in the sense that they don’t sink, but we find the posture to be extremely awkward. We also don’t rule out swimming, but in the posture the models adopt, it suggests moving around the surface effectively and (relatively) efficiently like a duck would be tricky at best. They did float, and did swim, but they probably did neither (we think, currently, based on our results) in a very competent manner.

    Link to this
  24. 24. David Marjanović 7:47 am 12/29/2013

    When people say “Lagerstätte”, they usually mean “Konservat-Lagerstätte”, a “storage/deposit site” where fossils are exceptionally well con- or preserved. The other type is the “Konzentrat-Lagerstätte” where fossils of unspectacular preservation have been concentrated – empty shells swept together, say; bonebeds probably qualify. An example that applies to pterosaurs might be the Cambridge Greensand with its lots and lots of pterosaur crumbs.

    The proposal that pycnofibers are stage 1 feathers became a lot more probable when the following abstract for this year’s meeting of the Society of Vertebrate Paleontology was published (p. 135 of the abstract volume, which will be uploaded here at some point as a huge pdf). Unfortunately, Pascal Godefroit wound up in hospital, so the talk has never been given – almost nobody has seen the pictures.

    FEATHER-LIKE STRUCTURES AND SCALES IN A JURASSIC
    NEORNITHISCHIAN DINOSAUR FROM SIBERIA

    GODEFROIT, Pascal, Institut Royal des Sciences Naturelles de Belgique, Brussels, Belgium; SINITSA, Sofia, Institute of Natural Resources, Ecology and Cryology, SB RAS, Chita, Russia; DHOUAILLY, Danielle, Université Joseph Fournier, La Tronche, France; BOLOTSKY, Yuri, Institute of Geology and Nature Management, FEB RAS, Blagoveschensk, Russia; SIZOV, Alexander, Institute of the Earth’s Crust, SB RAS, Irkutsk, Russia
    Recent discoveries in Middle–Late Jurassic and Early Cretaceous deposits from northeastern China have revealed that numerous theropod dinosaurs were covered by feathers. Furthermore, filamentous integumentary structures were also recently described in rare Early Cretaceous ornithischian dinosaurs from Liaoning Province in China. Whether these filaments can be regarded as epidermal and therefore part of the evolutionary lineage towards feathers remains controversial. Here we describe a new basal neornithischian dinosaur, based on isolated bones and partial skeletons collected in two monospecific bonebeds from the Middle–Late Jurassic Kulinda locality in the Transbaikal region (Russia). Varied integumentary structures were found directly associated with skeletal elements, supporting the hypothesis that simple filamentous feathers, as well as compound feather-like structures comparable to those in theropods, were widespread amongst the whole dinosaur clade. Moreover, scales along the distal tibia and on the foot closely resemble the secondarily-appearing pedal scales in extant birds. More surprisingly, dorso-ventral movements of the tail were prevented by large imbricated scales on its dorsal surface. It is hypothesized that, at the same time early feathers evolved within the whole dinosaur clade, genetic mechanisms limiting the growth of long epidermal structures on the distal portion of the hind limb and on the tail were selected as they facilitate bipedal terrestrial locomotion.

    But sitting on the water for hours, periodically sticking more of my body into it to get food, sleeping there even, requires, I think, thicker insulation than a little fur–

    Where do you get “a little” from? And fat layers or preening glands wouldn’t preserve.

    Link to this
  25. 25. Yodelling Cyclist 10:36 am 12/29/2013

    I’m now wondering how cold-adapted waterfowl avoid hypothermia in long range flight. I guess the airflow is quite cooling. Do large, arctic frequenting waterfowl tend to migrate at high altitudes?

    Link to this
  26. 26. Jerzy v. 3.0. 2:20 pm 12/29/2013

    @Dave Hone
    Could you enlighten those of us who cannot access your paper, what is ineffective?

    I saw geese and ducks in a zoo, swimming in a pool with the glass side. I can say that seen from the side, they look weird, ineffective and clumsy.

    A goose floats in a bent position, with the breast sinking almost completely because of flight muscles, rump with legs sticking up, and neck bent backwards and forwards.

    Long-tailed Duck dives with half-spread wings forming one panel withh the body, and big outstretched alulas sticking to the sides. It pushes clumsily with both legs and weirdly undulates the whole body up and down.

    I would understand some future zoologist who wouldn’t believe that waterfowl are swimming all their life.

    Link to this
  27. 27. Jerzy v. 3.0. 2:21 pm 12/29/2013

    @Yodelling Cyclist
    Many birds migrate at high altitudes. I am not sure how migrating birds avoid hypothermia from pumping lots of air through their bodies.

    Link to this
  28. 28. naishd 5:33 pm 12/29/2013

    Lots of good questions and comments here. Yod: knowledge of pycnofiber structure is in its infancy.. we can’t say much other than that they’re cylindrical. As for how migrating birds avoid hypothermia (and, as you’ve probably heard, there are birds that can fly at altitudes exceeding 6 km), the answer is (mostly) that they’re super-insulated.

    As for the position of pterosaurs and birds in the water, there are certainly some issues with the poses that Dave and Don depicted (they address these issues in their text) – Dave (Hone) and I have been discussing this, since neck, wing and hindlimb posture could all be different from the postures they adopted. But a start has been made and more work is needed. The key thing is that their project did not just involve arm-waving and guesswork – they used rigorous modelling, so at least you can say precisely which bits might be right, and which might be wrong.

    Link to this
  29. 29. Yodelling Cyclist 5:42 pm 12/29/2013

    naisd: knowledge of pycnofiber structure is in its infancy Oh, good. Stuff to look forward to then!

    I must apologise, earlier I thought “hyper-” and wrote “hypo-”. My error. I was actually wondering how a vigorously flapping super-insulated water bird avoided cooking itself. Something like one of the smaller auk species for example: lots of flapping with aerodynamically compromised wings (having been exapted for swimming). Especially in the warm summer when there maybe a need for long range foraging in relatively high air temps. Do they ever land on water to cool off? Or am I wandering into unknown territory. This is why I was wondering about big migrants: do they fly high just to stay cool, or are they avoiding the local topography?

    Link to this
  30. 30. Yodelling Cyclist 5:44 pm 12/29/2013

    Jerzy v. 3.0.: Thank you for sharing that about waterfowl posture at the surface. I had never thought about it in those terms. Cheers.

    Link to this
  31. 31. Tayo Bethel 2:00 am 12/30/2013

    I’ve read the book and agree on all good points–the witty comments are especially welcomein a scientific tome.

    On a side note, how much work has actually been done on aquatic avian swimming posture? Geese are terrestrial feeders (as far as I can remember), so need not be maximally adapted for aquatic locomotion. Would swimming posture reflect this?

    Link to this
  32. 32. Jenny Islander 2:41 am 12/30/2013

    In reply to the above two comments, the restorations in light of fossil evidence that I have seen show relatively lightly furred animals, more on the order of rabbits or weasels. The smallest mammals I can think of that regularly enter the water–mink, otters–are much more thickly furred than that, with extremely dense and conscientiously groomed coats that IIRC rely on trapped air more than on oil and a very high energy throughput. Galapagos fur seals have relatively thinner coats, but thicker blubber, while the ringed seal is even less thickly furred and semi-globular.

    But that’s mammal fur. How comparable was the stuff pterosaurs grew–better at trapping air, worse, about the same? Pterodaustro, for one, sure looks like a filter feeder, but that doesn’t automatically imply paddling around; it might have waded in very light surf like a shorebird, or used its four-point suspension to specialize in scrambling among tidepools instead. Could it have been plushy enough to allow for trapped air bubbles and high energy consumption to keep it warm with its butt in the water all the time? Or could it have taken off with the necessary amount of blubber on board?

    Link to this
  33. 33. Yodelling Cyclist 6:43 am 12/30/2013

    @Jenny Islander: As I understand it you are quite right that the trapped air the primary mechanism of insulation in mammal fur, and that this is aided by the double layered coats of sea otters etc., but this also true of feathers. The oil is present to make the hairs/feathers strongly hydrophobic – water repellent. This is what prevents these animals from becoming ultimately water logged.

    As for the smallest mammals to habitually enter the water, there are several species sub 100g. Here in Europe we have the water vole (IIRC, there is a species in North America), as well as two species of desman (echolocating semi-aquatic moles, tres cool), all of which frequent cold rivers/mountain streams. The tenrecs boast two species of dwarf otter shrew (might be just too big for this category) and the web-footed tenrec, which I recall Attenborough describing as being less than 50g in weight. The yapok may also be in the right weight range (help me someone!).

    Finally, rodents as a whole have thrown up quite a number of genera of small “water-mice” and “water-rats” which I’m not even going to attempt to list, because I’ll misspell the ones I remember and forget a large number of others. Wikipedia appears to have a good list:

    http://en.wikipedia.org/wiki/Water_mouse_(disambiguation)

    Xeromys definitely has members weighing <50g.

    Wondering how pycnofibres compare with fur was part of why I asked about what we know of pycnofibre structure. Daring to presume to expand on Darren's answer: it is unknown at this time how effective pterosaur integument would be at air trapping and water proofing. It sits in the "possible, not implausible, still unknown" category.

    As a fellow non-expert I too find the idea of swimming pterosaurs a bit counter-intuitive, and I do prefer the scenarios you have outlined. That said, there is not yet a strong reason to argue that no pterosaurs managed to swim habitually. David Horn's work (referenced above) argues against, but I believe there is some way to go before the matter is completely settled (although, having read the paper, I must say it appears an excellent, welcome and thorough start).

    For those who have real doubts about swimming pterosaurs, I invite you to use youtube to look for swimming bats. Several good videos have been uploaded and the bats seem to be doing just fine in the water (I appreciate there are major differences between a bat and a pterosuar, but it's probably the best modern analogue). Not sure if bats can launch off water though. Anybody know? I've seen Daubenton's bats crash land on water and swim to the edge before take off.

    Something which I find really odd about habitually swimming pterosaurs is that the patagium must have had been ennervated, had capillaries and a blood supply, and presumably was relatively hair less to reduce drag over the lifting surfaces (I'm sure there was hair on the wings in order for the animal to gain aerodynamic data about the flow of air over the wing). In short, it must have been poorly insulated yet thoroughly dunked when swimming. Not an insuperable problem compared with other soft tissue challenges/solutions in the animal kingdom, but still something the animals would have to get around.

    Best wishes,
    Yod

    Link to this
  34. 34. Jerzy v. 3.0. 7:04 am 12/30/2013

    Re: swimming and insulation.
    And there are, of course, water shrews Neomys fodiens and dippers Cinclus, which are smaller than fish-eating pterosaurs. They have some astonishing density of hair/feathers pers square cm.

    Pterosaurs could be as diverse as mammals and birds, from the poorly insulated tropical terrestrial ones to the densely furred (pycnofibrilled ? ;) ) aquatic and temperate pterosaurs.

    Link to this
  35. 35. Yodelling Cyclist 7:21 am 12/30/2013

    I’d also make the observation that when mammal/birds bodies get immersed in turbulent water, the integument is quite rapidly lost (hence the Montauk monster). So, gambling that something similar is true for pycnofibres, it’s going to be hard to say with certainty how thickly pycnofibrilled (love it, good one Jerzy!) a species was in life for all but the best taphonomies.

    Link to this
  36. 36. Cameron McCormick 9:20 am 12/30/2013

    @Yodelling Cyclist

    Walker’s Mammals of the World cites 604 to 790 grams for Yapok, but one recent mark-recapture found adult weights to be considerably smaller, between 395 and 595 grams.

    Galliez, M. et al. (2009) Ecology of the Water Opossum Chironectes minimus in Atlantic Forest streams of southeastern Brazil. Journal of Mammalogy 90(1) 93–103.

    Link to this
  37. 37. Yodelling Cyclist 9:51 am 12/30/2013

    Thank you Cameron McCormick. Good stuff. Today I learned that Yapoks are larger than I thought.

    Link to this
  38. 38. vdinets 11:12 am 12/30/2013

    Yod: I’ve seen small bats accidentally fall in the water a few times, and all of them, including one fishing bat, had to swim to shore to take off again. I would really like to know if Myotis vivesi (which fishes in the open sea) has this ability. Most, if not all, freetail bats can’t even take off from a horizontal hard surface, and have to climb trees or walls first. This is interesting because they are long-winged and more similar to pterosaurs in wing shape and size than other bats. This is one (not the only one) reason I am still skeptical of the quadripedal launch theory… but, of course, I am not an expert.

    Link to this
  39. 39. Dartian 11:32 am 12/30/2013

    Yodelling Cyclist:
    Here in Europe we have the water vole

    Even better: Europe has at least two water vole Arvicola species (three if the form found in the mountains of Central Europe is considered a full species rather than a subspecies).

    IIRC, there is a species in North America

    There is, although the American water vole Microtus richardsoni belongs to a wholly different lineage.

    And yes, as mentioned, the smallest extant semi-aquatic mammals are indeed various shrews; Neomys and Chimarrogale in Eurasia, and Sorex palustris and S. bendirii in North America.

    Link to this
  40. 40. naishd 11:45 am 12/30/2013

    The bats that fish at sea (and there are a few) are almost certainly similar in swimming abilities to bats that don’t fish at sea – however, if one does become dunked far from land, I’m pretty sure it would be in big trouble. An eagle that flops into the sea kilometres from land can make the slow and laborious ‘swim’ to land… I doubt that a tiny bat could do likewise. I’ve heard that some fruit bats are useless on the water, and simply flail around and drown (or get eaten by crocodiles) when they make aquatic crash-landings.

    As for the quadrupedal launch model (see comment # 38): pterosaurs are not bats, their anatomy is very different, and the key features linked to quad launching in pterosaurs are not involved in launch in bats. Having said that, it turns out that vesper bats (NOT just vampires) can take off from standing starts after all: check out this article over at Aero Evo.

    Link to this
  41. 41. Yodelling Cyclist 12:14 pm 12/30/2013

    What about the lesser short tailed bat? Being “terrestrial” bats, do these bats have a vertical launch capacity?

    Link to this
  42. 42. Gigantala 2:47 pm 12/30/2013

    Exceptionally late I am. Anyways:

    - “Little fur”? We have very few pycnofibril coats to judge from, and from what we have it’s very clear pterosaurs had lustrous pelages not unlike those of modern mammals. Hell, the only body parts in said specimens that seemingly lack pycnofibrils outside of post-mortem causes are the wing membranes (and even then, see anurognathids), and the foot soles (whose “scales” might very well be modified pycnofibrils anyways, if avian reticulae are of any indication).

    Long story short, it’s very inaccurate to say that pterosaurs had “little fur”. That, of course, doesn’t solve issues like whereas they had oil glands, whereas the fact that pycnofibrils being rooted far more shallowly in the skin than fur made insulation less efficient, et cetera.

    - I haven’t read the paper, so I’m not going to judge, but I find it odd that pterosaurs with adaptations specifically correlated to swimming (ctenochasmatoid hindlimbs, boreopterid filter feeding maws + short legs, pteranodontid lack of adaptations for aerial piscivory but coincidentally having traits interpreted as being associated with water based taking off, et cetera) if they supposedly could not swim regularly.

    - I’ve seen vesper bats taking off from the water, but I assume that must be a rare incidence. Alas, Mark Witton goes on a deep explanation as to a possible method of water based taking off in pterosaurs.

    - Pterosaur diversity is indeed correlated to Konservat-Lagerstätte; many groups are actually only known from that type of fossil site. Some features of pterosaur diversity might be genuine, like the predominance of azhdarchids in the late Mesozoic and the extinction of ornithocheirids at the middle of the Late Cretaceous, since neither group is tied to Konservat-Lagerstätte, but given how exceedingly and utterly rare forms like anurognathids or ctenochasmatoids are outside of Konservat-Lagerstätte, as far as one is concerned these groups’ history is nigh impossible to examine in detail other that they were extinct by the Cenozoic.

    Link to this
  43. 43. LeeB 1 4:22 pm 12/30/2013

    I have seen lesser short tailed bats on television moving around on the ground and burrowing through leaf litter and then shooting straight up in the air and flying away.
    So they do have a more or less vertical launch capacity.

    LeeB.

    Link to this
  44. 44. LeeB 1 4:33 pm 12/30/2013

    There are two short videos of lesser short tailed bats on ARKive; one shows one taking off.
    They are good at showing just how comfortable these bats are on the ground.

    LeeB.

    Link to this
  45. 45. Jenny Islander 12:47 am 12/31/2013

    OK, now I’m imagining a temperate zone pterosaur in a glossy covering that looks like a brightly colored penguin suit, crawling ashore, shaking out its shrunken bleached patagia, and holding them out to let them flush with fresh blood before taking flight.

    Perhaps a size limitation on year-round polar pterosaurs due to the need to have pycny little patagia, like fuzzy little ears on Arctic hares? Pteroptarmigans that burrow into the snow?

    Link to this
  46. 46. vdinets 3:43 am 12/31/2013

    Darren: vesper bats can easily take off from a flat surface (as you know, some species habitually hunt on land, like Pallid Bat), but freetails can’t. The only relevant difference between them (as far as I can tell) is the wing shape, with freetails having longer and more narrow wings. Notably, the only birds that have serious trouble taking off from flat land are swifts and albatrosses (the latter can only take off into strong wind), and they also have unusually long, narrow wings. That’s understandable since narrow wings generate very little lift at low speed, and hit the ground before you can complete the downward movement.

    I remember some pterosaur fossils with wings looking very swift-like in shape. It could be that the wing membrane shrunk a bit post-mortem, but they still could have trouble taking off from flat land. Of course, the relation between wing shape and launching ability is not so simple: note that sea-eagles can’t take off from the water while ospreys can, even though osprey wing seems to be longer and more narrow.

    Interestingly, the tricks that bats use to increase lift (using the uropatagium, bending inner fingers to “put down the flaps”) were not available to pterosaurs. Every time I think about the quadripedal launch theory, I imagine an azhdarchid at the moment when it has just extended all four legs to jump up. It is now rapidly falling back to the ground, and it needs to move its forelimbs (fully extended downwards, except for the flying finger) all the way up (presumably still folded), then unfold them and then move down again, and to generate enough lift in just one downward stroke to prevent the wingtips from hitting the ground.

    How high could they jump during the launch? Had to be at least two full wing lengths. Apparently other people can visualize this, but I can’t. What am I missing?

    Link to this
  47. 47. Jerzy v. 3.0. 5:59 am 12/31/2013

    Ptarmigan at rest have wings concealed almost completely in body plumage. Which produces a surprise effect when a grey bird turns white in flight.

    Another trick open to pterosaurs could be that wing membranes were partially covered with pycnofibrils and partially protected by long pycnofibrils on the body and fleshy parts of the arms. Pterosaur might dive holding wings in a fixed, semi-open position, like guillemots of long-tailed ducks.

    Link to this
  48. 48. David Marjanović 8:27 am 12/31/2013

    Interestingly, the tricks that bats use to increase lift (using the uropatagium [...]) were not available to pterosaurs.

    A uropatagium or perhaps cruropatagium is present in all fossils that are well enough preserved to tell.

    I imagine an azhdarchid at the moment when it has just extended all four legs to jump up. It is now rapidly falling back to the ground

    It jumps forward with the legs and upward with the wings. During the powerful upward jump, it has enough time to do an upstroke and prepare for a full downstroke – or for half a downstroke, enough for gliding away.

    Link to this
  49. 49. vdinets 11:38 am 12/31/2013

    David: long-tailed species like Rhamphorhynchus couldn’t use uropatagium for launch because their tail was too long. Short-tailed species like Pterodactylus didn’t even have enough of tail to have a large, independently controlled tail membrane.

    An Azhdarchid cannot even begin the upstroke until it has already finished the powered part of the jump and its forearms are fully extended downwards. It has to do the entire upstroke and the downstroke in the fraction of a second it takes it to fall back down. And it will be falling fast, because the upstroke will accelerate falling of the body. By the time it is back to the height of extended arms, it can no longer do the downstroke because it would break the wingtips, so it has to start another upstroke, this time with extended wings, again pushing the body downwards. That’s why I am saying it has first to jump up to twice the full wing length to launch successfully.

    Birds don’t have this problem, because they can jump up with the wings already extended upwards, and instantly do the downstroke. The heavier ones can even run on hind legs while making repeated partial downstrokes and gaining speed and lift. Azhdarchids would have only one downstroke to instantly generate a huge amount of lift, enough to stop their fast fall back to the ground and launch them upwards. And they would have to do it at very low horizontal speed, generated by just one push of their relatively short hind legs.

    Link to this
  50. 50. Heteromeles 12:09 pm 12/31/2013

    @vdinets: Hmmm. Good to watch a condor take off (kind of a crappy version at https://www.youtube.com/watch?v=09lbRZcoC2E). I don’t think that bird is jumping into the air.

    Link to this
  51. 51. Gigantala 12:18 pm 12/31/2013

    - Pterosaur cruropatagiums were seemingly unattached to the tail, uniting both legs. While derived pterodactyloids seemingly lost most of the cruropatagium, early pterosaurs could still confortably use it in the same manner as bats, since the tail would not interfere and the surface area to provide lift was still proportionally huge.

    - Pterodactyloid pterosaurs had:

    A) massively elongated manus (or at least fourth metacarpals, since many pterodactyloids reduced the metacarpals I-III to simply stubs attached to the end of the fourth metacarpal)

    B) rather large wing finger muscle complexes, implicating it’s role in catapulting the animal off the ground

    As examined in Habib’s paper, these two factors alone would generate tremendous power in the launching strike, effectively raising the animal off the ground entirely on the fraction of a second. Then, it would only need a wing stroke to reach enough elevation for flight to commense properly, this being especially true for short wing-fingered species like azhdarchids, in which the contact between the wing finger and the ground would be very rapidly reduced, and the low aspect ratio wings would allow a faster elevation. This is not getting into the complicated scapulocoracoid implicated muscle systems which would have further aided in the generation of kinetic power for the jump.

    Also, azhdarchids had proportionally very long hindlimbs. The only pterodactyloids with reltively short hindlegs are ornithocheiroids, and in their case this actually aided the animal in taking off, particularly in aquatic settings.

    Link to this
  52. 52. Gigantala 12:28 pm 12/31/2013

    Long story short, Habib’s paper has the answers for these issues. Amusingly enough, only David Peters has read it, with Averianov and Sankar admitting to have not read it, which is rather shameful for supposedly professional writers.

    Link to this
  53. 53. Yodelling Cyclist 12:40 pm 12/31/2013

    @vdinets: these things are hard to visualise. This is why we have maths. It’s wonderful stuff. ;-)

    Link to this
  54. 54. Stripey_cat 2:45 pm 12/31/2013

    Thanks for posting this review. I’d been meaning to buy a copy for months, and this finally reminded me to do so. It arrived today, and is a gorgeous book. (Also, pterosaur skeletal anatomy is *wierd* to a layman.)

    Link to this
  55. 55. Tayo Bethel 3:41 am 01/1/2014

    Might some piscivorous pterosaurs have been plunge divers like modern terns?

    Link to this
  56. 56. Gigantala 11:36 am 01/1/2014

    Plunge diving has been suggested for pteranodontids, though AFAIK it has been dismissed on the grounds of skeletal “fragility” (this was when pterosaurs were thought to be living baloons rather than normal animals, so unlikely to be a justifiable explanation) and due to their crests (a more reasonable grievance, but still probably unlikely given how pteranodontid crests are rather small and oriented towards the back of the skull)

    Link to this
  57. 57. Yodelling Cyclist 1:23 pm 01/1/2014

    @Gigantala: ctenochasmatoid hindlimbs….pteranodontid lack of adaptations for aerial piscivory but coincidentally having traits interpreted as being associated with water based taking off, et cetera

    Could you expand a little on this please (if you get time)? Most interesting.

    Also: given how exceedingly and utterly rare forms like anurognathids or ctenochasmatoids are outside of Konservat-Lagerstätte, as far as one is concerned these groups’ history is nigh impossible to examine in detail other that they were extinct by the Cenozoic.

    Just to play Devil’s advocate: why are we so confident of that last conclusion?

    Happy New Year
    Yod

    Link to this
  58. 58. Margaret Pye 1:57 pm 01/1/2014

    Is it possible to solidly prove anurognathids were extinct? If there were anurognathids flitting round the New Guinea Highlands (camouflaged nocturnal ones, maybe), why would Western science have noticed them?

    (Meanwhile, the locals consider them to be the result of bats having illicit love affairs with owls, everyone knows those bats and owls are always at it…)

    Highly unlikely, but would it be scientifically plausible :-) ?

    Link to this
  59. 59. Gigantala 3:09 pm 01/1/2014

    “Could you expand a little on this please (if you get time)? Most interesting.”

    Ctenochasmatoid hindlimbs have large feet and are more robust and muscular than normal for a pterosaur. This has been interpreted as adaptations for propulsion, supported by swimming tracks.

    Pteranodontids lack adaptations in the neck vertebrae correlated with dip feeding on aerial pterosaurs, but have scapulocoracoid adaptations that Mark Witton has interpreted as correlated with water based taking off.

    “Just to play Devil’s advocate: why are we so confident of that last conclusion?”

    As far as I am concerned, there are no Cenozoic pterosaur fossils, so they must have gone extinct in the KT-event.

    Link to this
  60. 60. David Marjanović 4:06 pm 01/1/2014

    An Azhdarchid cannot even begin the upstroke until it has already finished the powered part of the jump and its forearms are fully extended downwards. It has to do the entire upstroke and the downstroke in the fraction of a second it takes it to fall back down. And it will be falling fast, because the upstroke will accelerate falling of the body. By the time it is back to the height of extended arms, it can no longer do the downstroke because it would break the wingtips, so it has to start another upstroke, this time with extended wings, again pushing the body downwards. That’s why I am saying it has first to jump up to twice the full wing length to launch successfully.

    The jump consists of extending the forearms fully downwards. This is done with so much power that inertia carries the pterosaur much higher. As far as Michael Habib and James Cunningham have done the math, there’s time for a whole upstroke during this inertial rise.

    And they would have to do it at very low horizontal speed, generated by just one push of their relatively short hind legs.

    That plus the forelimb jump adds up to a lot of horizontal speed. Again, the math has been done. Do not try, as David Peters is doing, to just intuit your way through all of this.

    @vdinets: Hmmm. Good to watch a condor take off (kind of a crappy version at https://www.youtube.com/watch?v=09lbRZcoC2E). I don’t think that bird is jumping into the air.

    I see it run and jump, even from its high perch. It’s been measured that even hummingbirds get 80 % of the force necessary for taking off – and not just from the ground! – from jumping.

    massively elongated manus (or at least fourth metacarpals, since many pterodactyloids reduced the metacarpals I-III to simply stubs attached to the end of the fourth metacarpal)

    While mc I–III can become very thin indeed, they never shorten*; they always keep spanning the entire distance from the wrist to the fingers and remain as long as mc IV.

    * I have no idea about Nyctosaurus, a likely candidate for an exception.

    Is it possible to solidly prove anurognathids were extinct? If there were anurognathids flitting round the New Guinea Highlands (camouflaged nocturnal ones, maybe), why would Western science have noticed them?

    Why wouldn’t they spread, and why would they have stayed out of the fossil record for so long? What would confine them for so long? And when was any part of NG first lifted out of the sea – in the Miocene perhaps?

    As far as I am concerned, there are no Cenozoic pterosaur fossils, so they must have gone extinct in the KT-event.

    In particular, they’re so far absent from all Late Paleocene and Early/Middle Eocene Konservat-Lagerstätten (Fur Fm of Denmark, Green River Fm, Messel…), so they were almost certainly extinct by then. There are no Early Paleocene or for that matter Late Cretaceous terrestrial Konservat-Lagerstätten, so we can’t pinpoint their extinction to the K/Pg boundary event, but that’s the most parsimonious option…

    unless Dendrorhynchoides curvidentatus is Jurassic in age like D. mutoudengensis is, because then no Cretaceous anurognathids are known at all, and the poorly understood J/K boundary event(s?) become(s?) the most parsimonious candidate. Ah, the joys of obtaining fossils from illegal dealers.

    Link to this
  61. 61. Yodelling Cyclist 5:15 pm 01/1/2014

    Thank you for the responses. Particularly regarding the apparent aquatic pterosaur adaptations. As many will have recognised, I am one of the legion of very-much-amateur enthusiasts curious about why and how group x survived the KT event and not group y. Still curious as to how/why globally distributed, long range flying, endothermic pterosaurs get eliminated and birds don’t.

    As far as I am concerned, there are no Cenozoic pterosaur fossils, so they must have gone extinct in the KT-event.

    Certainly enormously plausible and by far the most likely scenario. I’m simply struck that for certain groups of pterosaurs we are only able to observe them through relatively rare fossilisation events, so our understanding of their diversity through time is necessarily somewhat approximate – to an even greater degree than usual in the fossil record. For comparison, early bats are obscure in the fossil record, and were likely comparable in size/bone durability to small pterosaurs.

    Pure idle speculation.

    I would also point out to anyone who wants to believe in the survival into modern times of pterosaurs: you can never, ever, prove an extinction. All that happens is the signal is lost from the fossil record. There is (I think) a difference in speculating about survival of some Cenozoic groups some small way into the Mesozoic based on the necessarily incomplete faunas recovered from relatively geographically scattered sites (hence my somewhat fanciful but not utterly ridiculous interest in the possibility of a post KT non avian dinosaur fauna on Zealandia), and suggesting that a major Cenozoic terrestrial group survive as far as the present without leaving a fossil record, or being directly observed.

    Link to this
  62. 62. Gigantala 7:19 pm 01/1/2014

    “While mc I–III can become very thin indeed, they never shorten*; they always keep spanning the entire distance from the wrist to the fingers and remain as long as mc IV.”

    Acthelly, in Pteranodontia and Neoazhdarchia (and maybe in isolated cases in both Tapejaridae and Istiodactylidae, according to the book), the metacarpals I-III ceased to be connected to the wrist altogether, being locked at the end of the fourth metacarpal. They also seem much shorter.

    “…unless Dendrorhynchoides curvidentatus is Jurassic in age like D. mutoudengensis is, because then no Cretaceous anurognathids are known at all, and the poorly understood J/K boundary event(s?) become(s?) the most parsimonious candidate. Ah, the joys of obtaining fossils from illegal dealers.”

    There’s also the Candeleros specimen to consider (granted, it is only certain to be non-pterodactyloid, but since rhamphorhynchines are known outside of KL it is more plausible that it is an anurognathid than some other more conspicuous non-pterodactyloid pterosaur)

    ” Still curious as to how/why globally distributed, long range flying, endothermic pterosaurs get eliminated and birds don’t.”

    99% of all known Late Cretaceous avian taxa died alongside pterosaurs, so it is hardly surprising.

    “I’m simply struck that for certain groups of pterosaurs we are only able to observe them through relatively rare fossilisation events, so our understanding of their diversity through time is necessarily somewhat approximate – to an even greater degree than usual in the fossil record. For comparison, early bats are obscure in the fossil record, and were likely comparable in size/bone durability to small pterosaurs.”

    Many vertebrates are only known in KL. If not for their teeth, Mesozoic mammals would be vritually absent from the fossil reccord, for instance.

    Bats are indeed a good model for pterosaur distribution in the fossil reccord. Aside from rhamphorhynchine Rhamphorhynchidae, the only pterosaurs that occur at an acceptable presence outside of KL are large pterodactyloids.

    Link to this
  63. 63. vdinets 2:30 am 01/2/2014

    Heteromeles (#50): the video clearly shows that the condor needs a bit of a run-up to successfully take off from level ground.

    Gigantala (#52): I’ve read Habib’s paper; it doesn’t answer any of my questions. All it says is that humeri of large pterosaurs are more massive than expected based on scaling bird bones. How high could they jump? What horizontal speed could they achieve by jumping? What was the stalling speed? How much time did they have for upstroke and downstroke before falling back from jump height?

    Yod (#53) Math can’t tell you how an animal moves until you imagine certain movements and test their possibility by creating models (always simplified) and testing them mathematically. I can propose that dogs move by repeatedly tumbling over their heads, and math would confirm that such movement is physically possible, but somehow it looks unlikely and ridiculous when you try to imagine it.

    David (#60): Habib and Cunningham have done all the math? I’ve read Habib (2008) and Witton & Habib (3013), but didn’t find anything close to “all the math”. There is a reference to “unpublished data” in the latter paper, and an illustration showing an azhdarchid in grasshopper-style launch, with puny hind limbs dangling behind. But insects launching in this manner never exceed a few inches in length, and they can start wing flapping instantly because their wings are fully independent of their legs.

    I am really curious about these unpublished data, and I wonder why it wasn’t included in the paper that would have benefited greatly from having it.

    Could azhdarchids really leap 6-10 m into the air? We all know Dromeosaurs could do it, because they’ve done it in Jurassic Park movie (under the stage name Velociraptor), but the largest azhdarchids were apparently even heavier?

    Link to this
  64. 64. Gigantala 7:59 am 01/2/2014

    “I’ve read Habib’s paper; it doesn’t answer any of my questions. All it says is that humeri of large pterosaurs are more massive than expected based on scaling bird bones. How high could they jump? What horizontal speed could they achieve by jumping? What was the stalling speed? How much time did they have for upstroke and downstroke before falling back from jump height?”

    Rather bizarre strange, then. The paper I have read explains the mechanics of the launch, why the propulsion generated would launch the animal entirely into the air in the fraction of a second (as my previous comment explains), leaving only the need of a single upstroke for flight to commense.

    Does not matter, the mechanism is explained in further detail in Pterosaurs.

    “But insects launching in this manner never exceed a few inches in length, and they can start wing flapping instantly because their wings are fully independent of their legs.”

    Really? We’re comparing azhdarchids to insects now? You do realise that actual vertebrates, bats, do this, and they weight far more than any grasshoper, right?

    “Could azhdarchids really leap 6-10 m into the air? We all know Dromeosaurs could do it, because they’ve done it in Jurassic Park movie (under the stage name Velociraptor), but the largest azhdarchids were apparently even heavier?”

    - Long story short, yes, azhdarchids could leap that high using the forelimbs. More so, like modern vampire/short tail bats, their short wings would allow almost instantaneous vertical climbing once the forelimbs rose.

    - …what? What do dromaeosaurs, who used their hindlimbs, have anything to do with this!? And you’re using them as an example because they jumped high in Jurassic Park?

    Link to this
  65. 65. Biology in Motion 11:28 am 01/2/2014

    There still seems to be some important misunderstandings with regards to quadrupedal launch. vdinets: I hope this helps clarify a bit.

    1) Large, long-winged animals fly with proportionally smaller flapping amplitude. It is relatively simple to get a rough prediction of flapping amplitude for giant pterosaurs using Strouhal Number constraints, and the amplitude was probably only 32 degrees or less at the shoulder. This means that the required height of the shoulder to prevent a major wingtip strike is only 3.5 meters or so. Given that a large azhdarchid stood with a shoulder about 2.5 meters off the ground, this means only a net height gain of 1-1.5 meters is needed during the leap. It does not need to get many meters high during the jump.

    2) Timing is indeed the constraint for quadrupedal launch, since it adds an upstroke. However, in practice, the addition of wing muscle propulsion for the launch initiation adds so much additional power that quadrupedal launch is almost always going to be better than bipedal launch – birds don’t use bipedal takeoff because it’s more powerful, they use it because they are constrained as bipeds. In fact, during water launching, some birds do use quadrupedal launch, and these are the only birds that can water launch without a run.

    3) To get an idea of this timing, we can use equations developed by Pennycuick some years back (see his 2008 book) for flapping rates based on span, mass, air density, and wing area. The expected total flap cycle time for a large azhdarchid comes out to about 0.9 seconds. So a standard upstroke is about 0.4 seconds. The initial upstroke could be performed must faster, however, since the wing was still folded. Pennycuick has shown that the flapping rate is proportional to Mass^(3/8), Span^(−23/24), and (Wing Area^(−1/3). With a folded wing, the upstroke time for a large azhdarchid is about 0.079 seconds. Even with a modest preload (not using tendon catapult storage), and the minimum leaping height, the same animal should have about 0.4 seconds to work with for this stroke – so it has a safety factor of about 5.

    4) The reason that swifts and molossid bats have trouble taking off from the ground is not that their wings are long; it’s because they have a weak terrestrial gait that prevents effective leaping. Their wings aren’t even all that long, per se – it’s mostly that the chord of the wing is short (making it high aspect ratio). Swiftlets have shorter wings, in fact, and still have trouble from the ground. Albatrosses get cited left and right as examples of all sorts of launch issues, but they are an extremely specialized group of flyers. They are gust specialists on the wing and during launch. They are also more adapted to water takeoff than ground takeoff. They have high wing loadings with short legs placed very far back on the body, which makes effective leaping difficult. The running gust launch of albatrosses is a specialization to their high gust environments.

    5) There need not be only one kind of quadrupedal launch. I proposed one possible kinematic back in 2008, but perhaps other, better models will be proposed. Mostly what I demonstrated is that the mechanics of pterosaur bones match much more closely the expectations from a quad launch model than a biped launch model. This is not surprising, since any animal that is quadrupedal on the ground would be expected to be a quadrupedal launcher.

    Link to this
  66. 66. Biology in Motion 11:47 am 01/2/2014

    A couple other quick clarifications:

    “Azhdarchids would have only one downstroke to instantly generate a huge amount of lift, enough to stop their fast fall back to the ground and launch them upwards”

    The circulation delay on a flat plate started impulsively has been shown to be less severe than previously thought (Becwith and Babinksy, 2009). Roughly speaking a pterosaur wing should manage 85% of maximum circulation at about one chord length of travel. Interestingly, though, the high acceleration associated with wing opening would reduce this delay even further – over 90% maximum CL in only half a chord length or so. That first downstroke might not see a huge gain in height, but it will keep the animal up, as best anyone can tell. Climb out can then begin under anaerobic burst power (for large species). Smaller taxa would be able to climb out after launch under aerobic capacity (and probably gain height on the first downstroke, as well).

    “That’s understandable since narrow wings generate very little lift at low speed…”

    All wings produce very little lift at low speed – that’s a major component of why animals leap to take off. Long, narrow wings actually produce less induced drag at low speeds than short, broad wings, making them a bit more efficient on the slow speed end of things. If the span is unchanged but the chord is broader then the total area increases, and this does reduce the minimum flight speed. This is probably a major factor in the evolution of broader wings among burst-launching terrestrial birds. Interestingly, azhdarchid pterosaurs may very well have had slightly broader chord wings than other large pterosaurs (Work by Mark Witton, Darren Naish, etc).

    Reference:
    Beckwith, R. M. H. and Babinsky, H. (2009). Impulsively started flat plate flow, Journal of Aircraft, Vol. 46(6):2186–2188

    Link to this
  67. 67. vdinets 12:30 pm 01/2/2014

    Biology in Motion: thanks a lot! That answers all my questions.

    Gigantala: I meant the 2008 paper; which one are you talking about? There is no reason to not compare vertebrates and large insects; the laws of physics are the same. You cannot do it for smaller insects because the viscosity of air doesn’t scale down in a linear way, but large grasshoppers are totally OK, and don’t forget that they can be as heavy as small bats. The Jurassic Park reference was, of course, a joke.

    Link to this
  68. 68. David Marjanović 6:31 am 01/3/2014

    Long ago I saw a slow-motion movie of a large grasshopper launching. It only unfurled the wings near the highest point of the jump and then flew away from there. Indeed, the filmers may not have noticed the wings at all; the movie was just meant to show how grasshoppers jump, and the commentary never mentioned wings or flying. The intended audience were children from, say, 5 to 12.

    Link to this
  69. 69. Yodelling Cyclist 7:31 am 01/3/2014

    Biology in Motion: I appreciate this is a long shot, but have you done any talks which would be available online on this subject?

    Best Wishes for the New Year
    Yod

    Link to this
  70. 70. Yodelling Cyclist 3:04 pm 01/4/2014

    @Gigantala: Many vertebrates are only known in KL. If not for their teeth, Mesozoic mammals would be virtually absent from the fossil record, for instance.

    Sure, and I’m sure I’m not as aware of the subtleties of this issue as many others in this thread, but is it not the case that Mesozoic and Cenozoic mammals continually throw up surprises? I seem to recall Darren doing a serious post about shockingly late surviving dicynodonts a few years ago, the St. Bathan’s animal is….weird, and surprising, and I’m sure there’s been at least one thread discussion about how long multituberculates survived and serious debate about some fossil evidence.

    My point is this: small, hard to fossilise animals are hard to pin down in terms of spatial distribution and temporal span. (I’m not advocating living pterosaurs, or even late surviving ones! I’m just stating that it’s hard to really pin down these things for some troublesome animals. Like bats, for instance, or even proto-pterosaurs, small light animals are, on taphonomic grounds, prone to ghost lineages.).

    Link to this
  71. 71. Yodelling Cyclist 3:04 pm 01/4/2014

    @Gigantala: Thanks for taking the time to respond, btw..

    Link to this
  72. 72. Halbred 9:05 pm 01/5/2014

    I’m surprised nobody answered Yodelling Cyclist’s polar pterosaur question. I BELIEVE there are azdarchid wing bones known from Australia and the North Slope of Alaska. Since these critters could travel huge distances, I’m not surprised they are found top-to-bottom.

    Link to this
  73. 73. Gigantala 8:23 am 01/6/2014

    There’s also pterosaurs from supposed antarctic australian sites and Liaoning. It’s pretty clear several pterosaurs lived in polar areas, and thus they would have possibly been migratory.

    Link to this
  74. 74. Yodelling Cyclist 9:49 am 01/6/2014

    Interesting and thanks, but I was really wondering (with a badly phrased question) if there was any reason to think there might be resident pterosaurs at very high latitudes (to compliment the supposed resident high latitude dinosaurs). I was hoping that this might give a pointer on pycnofibre insulation capabilities.

    Link to this
  75. 75. Gigantala 12:55 pm 01/6/2014

    You mean sedentary pterosaurs, instead of say migratory ones? We know so little about live pterosaurs that it’s impossible to know if the polar pterosaurs migrated or not, though I think there’s no reason to assume all migrated, especially when polar conditions weren’t so extreme. Tapejarids, for instance, are among Liaoning’s pterosaur fauna, and they seem to have been relatively poor flyers, so they could had been sedentary.

    Link to this
  76. 76. Gigantala 5:45 pm 01/11/2014

    Here is a rebuttal to Henderson and Hone 2013:

    http://gwawinapterus.wordpress.com/2014/01/11/oh-yes-they-float-henderson-and-hone/

    Link to this
  77. 77. David Marjanović 3:46 pm 01/13/2014

    Here is a rebuttal to Henderson and Hone 2013:

    I’m not sure it works. I’ve commented there.

    Link to this

Add a Comment
You must sign in or register as a ScientificAmerican.com member to submit a comment.

More from Scientific American

Scientific American Holiday Sale

Black Friday/Cyber Monday Blow-Out Sale

Enter code:
HOLIDAY 2014
at checkout

Get 20% off now! >

X

Email this Article

X