Monday, 1 September 2014

The accuracy of palaeoart and the 'new' Spinosaurus

Spinosaurus, big and small versions, poking about a stream in Cretaceous Morocco. Someone's about to ask if these chaps should have humps or sails - head to Palaeontology Online for my thoughts on this, and read on for why it doesn't resemble the (in?)famous National Geographic thumbnail.
Corking news, all: I've got a new article out at Palaeontology Online on the accuracy of palaeoart, explaining how confident - or not - we can be about different aspects of extinct animal appearance. It features two new bits of palaeoart, a Spinosaurus and a bizarre - but not implausible - reconstruction of Camarasaurus. The former started life as a simple illustration to make a point about reconstructing fatty tissues (including camel-like humps) in fossil animals, but I thought it warranted some elaboration: the painting above is the result.

The goal of the Palaeontology Online piece is not another 'how to?' guide to palaeoart, but a piece specifically targeted at those who want to know how accurate our restorations are. I've attempted to outline the reliability of standard palaeoart methods including phylogenetic bracketing, restoring musculoskeletal systems, placing fatty tissues, choosing integument types and, of course, deciding on colours and patterns. Note that the few years of optimism we've had for restoring fossil colour using melanosomes are over, because several new studies have highlighted numerous concerns with this technique: more on that at Palaeontology Online. All Yesterdays gets further mainstreamification, as does the mysterious, unexplained 'Support Original Palaeoart' logo (more on that in due time), and there's some philosophising over the goal of palaeoartists: are we actually bothered about 'the truth', or more concerned with making plausible art in line with fossil and biological evidence? OK, that's enough signposting for now: point your browser this way for the full piece, and be sure to leave any feedback below.

Just a quick note on the Spinosaurus illustrations here and in the article: they are not based on the thumbnail image of a unusual Spinosaurus skeleton at the National Geographic website, despite this spawning much excitement, umpteen new spinosaur renditions and revisions to Spinosaurus illustrations all over the Web. As stressed at Palaeontology Online, palaeoart is a scientific process requiring verified and trustworthy data. We have no idea how reliable the radical National Geographic depiction of Spinosaurus is because no information about the mount has been made public, and the image itself is tiny: it's silly to think there's enough resolution there to understand its anatomy. Moreover, there's enough counter-intuitive and weird morphology in that tiny photo to justify waiting for the data behind the mount to be published so it's accuracy can be evaluated. I'm not saying it's wrong, but I am joining the chorus of bona fide theropod experts in suggesting restraint against adopting it as the 'definitive new look' for Spinosaurus until we know more about it. The reconstructions here and at Palaeontology Online are based on Scott Hartman's skeletal: the appearance of the juveniles is speculative.

Coming soon (probably): exciting news from the world of sauropods!

Friday, 22 August 2014

Scleromochlus taylori: more than just 'the early ornithodiran'

The Triassic ornithodiran Scleromochlus taylori depicted as a nocturnal desert-specialist with filamentous insulation, fuzzy feet for purchase on drifting sands and a saltatorial means of locomotion. 

Like actors with one famous character, fossil taxa can become typecast to specific ‘roles’ in palaeontological discussions. One fact of their palaeobiological significance is entrenched so deeply that they are seldom mentioned outside of this context. Examples include Archaeopteryx as the first bird, Mei as the cute sleeping dinosaur, and Darwinopterus as the bridge between major stages of pterosaur evolution. Packaging these animals into simple factoids obscures much of their other interesting palaeobiology, so we rarely hear about their other remarkable features.

Step forth Scleromochlus taylori, a small Triassic archosaur from the Upper Triassic (Late Carnian) of Scotland. For 100 years Scleromochlus has been implicated as a relative of pterosaurs (e.g. Huene 1914; Padian 1984; Gauthier 1986; Sereno 1991; Bennett 1996; Hone and Benton 2008; Brusatte et al. 2010, Nesbitt 2010) or, at very least, an ornithodiran representing a very early stage of stem-bird evolution (Benton 1999; Hone and Benton 2008).* This is about all we ever hear about Scleromochlus, however: nothing more than a milestone in the evolution of pterosaurs or dinosaurs. I'm guilty of it too: in my own book, Pterosaurs (Witton 2013), Scleromochlus just formed an anchor for discussing ornithodiran evolution. Undoubtedly, this needs correcting: Scleromochlus is a unique and interesting animal in its own right, and one fully worthy of detailed discussion. To relieve my shame, I'm going to attempt such a discussion here. Just for fun, I'm going to write it in the same style as a Pterosaurs chapter.

*You can't mention Scleromochlus on the internet without someone pointing out that its status as an ornithodrian has not been tested in analyses containing non-archosaur archosauromorphs. This is true enough, but - at least within the current limits of testing - its ornithodiran status is not controversial, having been recovered in at least six different analyses (e.g. Gauthier 1986; Sereno 1991; Bennett 1996; Hone and Benton 2008; Brusatte et al. 2010) and sharing several unique characteristics with Pterosauria (Padian 1984). Hence, we're following convention here.

Select line drawings of Scleromochlus taylori fossils from Benton (1999). There are two specimens here, showing dorsal and ventral views. The specimen on the right is the holotype, and the left shows two associated individuals. Note the banded scales crossing the vertebrae of the larger individual.
Although represented by at least seven specimens from the Lossiemouth Sandstone Formation, no Scleromochlus is well preserved (Benton 1999). Most specimens comprise shallow sediment molds rather than actual bones, and none are complete. But we should consider ourselves lucky we know of this animal at all: the delicate, 180 mm long bodies of Scleromochlus occur in sandstone deposits representing an ancient, wind-blown desert with 20 m high dunes. Such deposits are often devoid of fossil remains, but the Lossiemouth Sandstones actually preserve a diverse reptile fauna (Benton and Walker 1985). Still, it’s remarkable that the tiny bones of these reptiles preserved at all in these harsh conditions and in relatively coarse (fine - medium) sands - the grains preserving Scleromochlus are each as large as Scleromochlus teeth. As is typical of Lossiemouth Sandstone specimens, most Scleromochlus fossils are more-or-less articulated and many appear to have been crouching at death. With little indication of sun-cracking or scavenging, their remains clearly represent animals which were buried alive or buried shortly after death, probably by sandstorms or dune collapses (Benton and Walker 1985). Although likely complete when buried, no specimens have survived intact to the present. Cross-scaling elements from different specimens has permitted a reasonable insight into Scleromochlus anatomy all the same (Benton 1999). Some details remain murky however, and disagreement persists over precise bone lengths and skull bone attitudes (Sereno 1991, Benton 1999; Padian 2008). This is perhaps expected, given that Scleromochlus remains are interpreted via low-angle light and plaster or plastic peels of the skeleton molds. Bennett (1996) sums up working on Scleromochlus as "low-angle illumination [is used] to examine and interpret molds and peels, but in my experience a considerable amount of imagination is necessary as well".

Anatomy

Specific details aside, palaeontologists are happy to say that the basic bauplan of Scleromochlus resembles a small lizard with enormous hindlimbs (below). The skull has a low lateral profile but is rather triangular in dorsal aspect, with a blunt muzzle and widened posterior. So far as can be seen, the orbit is by far the largest opening in the skull, making the reduced nares look even smaller by comparison. The temporal fenestrae - as illustrated by Benton (1999) - are fairly sized, although their full margins aren't clear in any specimen. These sit above a posteriorly lengthened retroarticular process on an otherwise fairly unremarkable lower jaw. Each jaw seems to house 15/16 teeth, which are apparently isodont and - so far as can be seen - relatively small and lanceolate. The lizard-like visage of Scleromochlus is further enhanced by its short neck, which contrasts with later ornithodirans. The tail appears rather short too, being about as long as the snout-vent length.

Reconstructed skeleton of Scleromochlus taylori from Witton (2013), a modified version of the skeletal in Benton (1999).

The limbs of Scleromochlus are where a lizard-like visage starts to unstick. The forelimb bones are long and slender, and capped with tiny hands. The fingers are poorly known, but the tiny metacarpals suggest they were rather diminutive and unlikely of any use for standing or walking, a hypothesis supported by the dichotomy in fore- and hindlimb length. Even less lizard-like are the hindlimbs, which are extremely long - about half the length of the entire animal - and end with a narrow foot with tightly bound metatarsals. Both the forelimbs and pelvis appear relatively small compared to the legs, though neither is atypically small for the length of the animal. The fifth toe appears to have been lost, the only remnant being a short, pointed metatarsal. Scleromochlus hindlimb arthrology betrays a parasagittal posture akin to that of dinosaurs and pterosaurs - the suite of characteristics associated with this is one clue that Scleromochlus is closely related to these clades (Bennett 1996; Benton 1999; Hone and Benton 2008).

Thin, transversely-banded scutes(?) covered the dorsal surface of the Scleromochlus torso, extending from at least the shoulders to the posterior pelvic region (indicated in the fossil illustrations, above). These indicate that Scleromochlus was at least partly scaled, although whether this represents the entire integument is not clear. It is increasingly apparent that scraps of fossil skin do not tell whole stories about ornithodiran integuments, as more and more specimens with extensive skin preservation present 'mosaics' of scales, naked skin and various kinds of filaments (demonstrated in pterosaurs, theropods and ornithischians; e.g. Bakhurina and Unwin 1994; Chiappe and Göhlich 2010; Godefroit et al. 2014). Scleromochlus may have been covered in scales, but it is equally likely that it had fuzz-like filaments in places. There are several reasons for this. Firstly, it belongs within a phylogenetic bracket where filaments are the ancestral condition or, at very least, scales were prone to developing filamentous morphologies. Secondly, virtually all models of archosaur evolution recover Scleromochlus as sister taxon to a fuzzy clade - pterosaurs, so there is good 'phylogenetic proximity' for fuzz. Thirdly, insulating integuments are common - if not ubiquitous - in small, active (see below) desert-dwelling animals. Thus, while the overall  integument of Scleromochlus remains mysterious, a mosaic of filaments and scales is not an unreasonable suggestion. In the reconstruction here, Scleromochlus is shown as rather fuzzy all over (see below for rationale), with filaments poking through its scaly back as they do on opossum tails and armadillo hide.

Please provide your own 'boing' sound effects.

Locomotion

Scleromochlus has long been recognised as a sprightly, cursorial or saltatorial biped because of its elongate, parasagittal hindlimbs (e.g. Woodward 1907; Huene 1914, Walker 1961; Padian 1984; Benton and Walker 1985; Benton 1999; Witton 2013). It has also been considered an arboreal glider with Sharovipteryx-like hindlimb membranes, as well as an aquatic diver, but few obvious adaptations to these lifestyles are found on its skeleton (Benton and Walker 1985). Cursorial features of Scleromochlus include lengthening of the distal hindlimb, reduction of the lateral pedal digits and narrowing of the metatarsal, and it is generally considered to have assumed a digitigrade stance, at least when moving at speed. Several features indicate that Scleromochlus was a saltator rather than a running creature: a relatively small but strong pelvis, short trunk skeleton, and a pronounced intercondylar groove at the end of the femur, which likely reflects a large quadriceps femoris tendon (Benton and Walker 1985). Saltation is an energy-efficient means of locomotion which has frequently evolved in desert-living species - extant examples include desert rodents, jerboas and kangaroos - and Scleromochlus has been favourably compared with such animals on several occasions (Walker 1961; Benton and Walker 1985; Benton 1999). Saltation may seem unusual means for a reptile to move, but other Triassic ornithodirans may have also locomoted in this way (Sereno and Arcucci 1994). Indeed, the powerful leaping and bounding abilities of early ornithodirans has been tied to the evolution of pterosaur flight (Bennett 1997; Witton 2013). 

Lifestyle and palaeoecology

It is difficult to say exactly what Scleromochlus ate because its teeth are poorly known, but a generalised diet of insects and other small prey seems mostly likely given the shape of its teeth and jaws (Benton and Walker 1985; Benton 1999). The wide skull and enlarged retroarticular process may have provided space for large and powerful jaw muscles, allowing Scleromochlus to make short work of tough insect carapaces. The association of crouching, articulated Scleromochlus skeletons (see line drawings, above), along with the recovery of multiple specimens (actually 5% of the Lossiemouth Sandstone fauna - Benton and Walker 1985), hints at some degree gregarious behaviour. It is difficult to imagine how the two associated individuals shown above were preserved in such a way unless they were alongside each other when they died - huddled together against whatever catastrophe buried them. Was coupling or group living 'normal' behaviour in Scleromochlus? Statistically, the odds of rare fossil specimens like those of Scleromochlus preserving unusual, 'one in a million' types of behaviour are low, so we might take the co-preservation of two animals as being representative of 'average' or typical behaviour in this species.

For those of you now weeping about tiny, panicked pairs of Scleromochlus dying in huddled balls of fear, here's a speculative reconstruction baby Scleromochlus to cheer you up. Using back of the envelope calculations of lizard egg mass and size, I predict this gangly hatchling was 50-60 mm long. The image is deliberately displayed at this size to stress the tiny proportions: on my 'standard issue' laptop screen, it's about life-size. Click to embiggen.

The likely saltatorial locomotion of Scleromochlus may not be their only adaptation to desert life. Their metatarals are rather flattened posteriorly (Benton and Walker 1985), permitting sitting or squatting on plantigrade feet without sinking into sand. Their nares are small, and flanges from the back of the skull cover the tympanic region (the location of the ear opening), both adaptations common among modern xerocoles to prevent moisture loss and minimise irritation from wind-blown sands (Benton and Walker 1985). Their orbits, by contrast, are very large, and may reflect another common response to desert life - nocturnality. Tiny animals like Scleromochlus rapidly overheat under a desert sun, but foraging at night negates that risk. Of course, desert temperatures plummet once the sun sets, but a layer of filaments (if present) may have countered this. Perhaps groups of Scleromochlus spent their days under shelter - rocks or vegetation - before venturing out at night to forage for insects. This strategy also helps avoid predators, of which the Lossiemouth Sandstone Formation has its fair share: early dinosaurs and nimble pseudosuchians are likely predators of Scleromochlus (Benton and Walker 1985). Hypothetical filaments of Scleromochlus may have had further uses in desert life, including enhancing their grip - and therefore agility - on sandy substrates, as seen in some modern saltatorial desert species. Likewise, covering or filling nose and ear openings with long scales or fur is another feature common to desert species, enhancing resistance to evaporation and airborne sand. The desert habitat of this early ornithodiran presents several intriguing reasons for the development of filamentous structures, which is obviously of interest when considering the origins of fuzz in Ornithodira more broadly.

And that, in a way, brings us full circle: back to considering Scleromochlus anatomy in the context of wider Ornithodira. Still, I'm sure we can all agree Scleromochlus is actually a very interesting animal in its own right, and definitely worthy of escaping typecasting as 'the early ornithodiran'.

References

  • Bakhurina, N. N., & Unwin, D. M. (1995). A preliminary report on the evidence for ‘hair’in Sordes pilosus, an Upper Jurassic Pterosaur from Middle Asia. In Sixth Symp. Mesozoic Terrestrial Ecosystems and Biota, Short Papers (pp. 79-82).
  • Benton, M. J. (1999). Scleromochlus taylori and the origin of dinosaurs and pterosaurs. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 354(1388), 1423-1446.
  • Benton, M. J., & Walker, A. D. (1985). Palaeoecology, taphonomy, and dating of Permo-Triassic reptiles from Elgin, north-east Scotland. Palaeontology, 28(2), 207-234.
  • Bennett, S. C. (1996). The phylogenetic position of the Pterosauria within the Archosauromorpha. Zoological Journal of the Linnean Society, 118(3), 261-308.
  • Bennett, S. C. (1997). The arboreal leaping theory of the origin of pterosaur flight. Historical Biology, 12(3-4), 265-290.
  • Brusatte, S. L., Benton, M. J., Lloyd, G. T., Ruta, M., & Wang, S. C. (2010). Macroevolutionary patterns in the evolutionary radiation of archosaurs (Tetrapoda: Diapsida). Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 101(3-4), 367-382.
  • Chiappe, L. M., & Göhlich, U. B. (2010). Anatomy of Juravenator starki (Theropoda: Coelurosauria) from the Late Jurassic of Germany. Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen, 258(3), 257-296.
  • Gauthier, J. A. (1986). Saurischian monophyly and the origin of birds. In Padian, K. The Origin of Birds and the Evolution of Flight, Memoirs of the California Academy of Sciences 8. California Academy of Sciences, 1–55. 
  • Godefroit, P., Sinitsa, S. M., Dhouailly, D., Bolotsky, Y. L., Sizov, A. V., McNamara, M. E., ... & Spagna, P. (2014). A Jurassic ornithischian dinosaur from Siberia with both feathers and scales. Science, 345(6195), 451-455.
  • Hone, D. W., & Benton, M. J. (2007). An evaluation of the phylogenetic relationships of the pterosaurs among archosauromorph reptiles. Journal of Systematic Palaeontology, 5(4), 465-469.
  • Huene, F. von. (1914) Beiträge zur Geschichte der Archosaurier. Geologische und palaeontologische Abhandlungen, N.F., 13, 1-53.
  • Nesbitt, S. J. (2011). The early evolution of archosaurs: relationships and the origin of major clades. Bulletin of the American Museum of Natural History, 1-292.
  • Padian, K. (1984). The origin of pterosaurs. In Third Symposium on Mesozoic Terrestrial Ecosystems: Short Papers (pp. 163-166).
  • Padian, K. (2008). Were pterosaur ancestors bipedal or quadrupedal?: Morphometric, functional, and phylogenetic considerations. Zitteliana, B28, 21-33.
  • Sereno, P. C. (1991). Basal archosaurs: phylogenetic relationships and functional implications. Journal of Vertebrate Paleontology Memoir 2, 11, 1-53.
  • Sereno, P. C., & Arcucci, A. B. (1994). Dinosaurian precursors from the Middle Triassic of Argentina: Marasuchus lilloensis, gen. nov. Journal of Vertebrate Paleontology, 14(1), 53-73.
  • Walker, A. D. (1961). Triassic reptiles from the Elgin area: Stagonolepis, Dasygnathus and their allies. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 103-204.
  • Witton, M. P. (2013). Pterosaurs: natural history, evolution, anatomy. Princeton University Press.
  • Woodward, A. S. (1907). On a new dinosaurian reptile (Scleromochlus taylori, gen. et sp. nov.) from the Trias of Lossiemouth, Elgin. Quarterly Journal of the Geological Society, 63(1-4), 140-NP.

Wednesday, 13 August 2014

Lies, damned lies, and 'Thalassodromeus sebesensis'

Yesterday, a huge team of authors called out the science behind 'Thalassodromeus sebesensis', an alleged new pterosaur species 40 million years and thousands of miles out of time and space (Grellet-Tinner and Codrea 2014). As with many outlandish palaeontological claims, the evidence behind 'T. sebesensis' really falls apart rapidly under scrutiny, principally because the alleged pterosaur remains actually represent an unremarkable piece of turtle plastron (Dyke et al. 2014).

A, the plastron of the fossil Romanian turtle Kallokibotion magnificum, compared with B, the alleged holotype 'cranial crest' of 'Thalassodromeus sebesensis'. For further details, see yesterday's post.
Since then, the response to our comment has been published (Codrea and Grellet-Tinner 2014). I'll admit to being surprised that Codrea and Grellet-Tinner maintain the specimen as a pterosaur, and consider the arguments raised against our points as weak, hypocritical and problematic, but whatever: the two arguments are now out, and the palaeontological community can judge for themselves. CT scanning is apparently planned for the specimen (Codrea and Grellet-Tinner 2014), which should put 'T. sebesensis' to bed once and for all.

This post isn't really about that, though: it's about correcting a mistruth in Codrea and Grellet-Tinner's response. Their comment shows little decorum or professionalism, attempting to undermine our response with ad hominem potshots at some authors of Dyke et al. (2014), including criticism of their editorial skills and the taxonomic confusion surrounding specimens described by the authors. Moreover, they criticise us for not examining the specimen, UBB ODA-28, before publishing our response. They state that:
"...UBB ODA-28 is housed in an official and recognized Romanian institution, thus available for examinations to anyone interested. This includes Dyke’s July 2nd 2014 written request to examine UBB ODA-28, which was immediately granted, although, Dyke went on writing its hasty comment without examining UBB ODA-28."
Codrea and Grellet-Tinner, 2014, p. 3-4 (my emphasis)

Well, this isn't really true. Some of it is: Gareth Dyke did write to ask for permission to look at the specimen this year - specifically between July and September - but 'immediate' access was not granted. Rather, eventual access was promised following on-going studies, including CT scanning of the specimen, the dates of which was not disclosed. This is not, as Codrea and Grellet-Tinner describe, 'immediately' granting access, but nebulously promising access at an undetermined future date. 

This may not seem like a big deal, but our integrity is being questioned for having not seen the specimen, so we - the authors of Dyke et al. (2014) - think the record should be set straight. There's no doubt that examining specimens is the way forward in any research. But it was clear from Gareth's correspondence that accessing UBB ODA-28 was going to be difficult for the immediate future, and all the while the science behind 'T. sebesensis' remained extremely problematic and in need of swift rebuttal. Why? In short: none of us concerned with pterosaurs or European palaeontology want to deal with this outrageous, nonsensical claim in future publications. Hence, we fell back on using the published accounts of UBB ODA-28 to construct an argument against the pterosaur identification. Given that our authorship team has collectively amassed thousands of hours examining actual thalassodromid pterosaurs, as well as turtle plastrons, and how obvious the turtle affinities of the specimen are, this method seemed more than sufficient for the task at hand. Despite allegations from Codrea and Grellet-Tinner, these were not the actions of a team hastily assembling a rebuttal, but a collective of experienced individuals succinctly calling out obvious flaws in bad science.

So there we go: that's our side of that mistruth. Hopefully, that's the last we'll hear of 'T. sebesensis' around these parts, for there are much more interesting and exciting things to cover: palaeoart guides, Triassic fuzzy saltating xerocoles, dinosaur fat humps... all coming soon.

References

  • Codrea, V. A., & Grellet-Tinner, G. (2014). Reply to Comment by Dyke et al. on "Thalassodromeus sebesensis, an out of place and out of time Gondwanan tapejarid pterosaur" by Grellet-Tinner and Codrea (July 2014)"  Gondwana Research. IN PRESS
  • Dyke, G. J., Vremir, M., Brusatte, S., Bever, G., Buffetaut, E., Chapman, S., Csiki-Sava, Z, Kellner, A. W. A., Martin, E, Naish, D, Norell, M, Ősi, A, Pinheiro, F. L., Prondvai, E, Rabi, M, Rodrigues, T., Steel, L., Tong, H, Vila Nova B. C. & Witton, M. (2014). Thalassodromeus sebesensis-a new name for an old turtle. Comment on" Thalassodromeus sebesensis, an out of place and out of time Gondwanan tapejarid pterosaur", Grellet-Tinner and Codrea. Gondwana Research. IN PRESS.
  • Grellet-Tinner, G., & Codrea, V. A. (2014). Thalassodromeus sebesensis, an out of place and out of time Gondwanan tapejarid pterosaur. Gondwana Research. IN PRESS

Tuesday, 12 August 2014

'Thalassodromeus sebesensis': pterosaur out of time and space? Nope, just a misidentified chunk of turtle.

Thalassodromeus sethi after some worms. Note: not a turtle. From Witton (2013)
Today sees the publication of an article challenging an exciting claim made in recent pterosaurology (Grellet-Tinner and Codrea 2014). If you missed it, the article concerned identifies a thalassodromid pterosaur in uppermost Cretaceous rocks of Romania and the erects a new species, Thalassodromeus sebesensis Grellet-Tinner and Codrea, 2014. At the centre of this is ODA-28, an (alleged) fragmentary cranial crest only fully exposed on one surface. None of this may not sound like a big deal, except that other thalassodromids - including the alleged sister species, Thalassodromeus sethi - are only known from the Lower Cretaceous Araripe Group of Brazil. T. sebesensis thus is about 40 million years out of time and thousands of miles out of place, and also occurring when azhdarchid pterosaurs basically represent the entire diversity of Pterosauria (Grellet-Tinner and Codrea 2014). Suddenly, the routine act of naming of a new animal is rewriting our understanding of pterosaur evolution.

There's more. Despite having only a scraps of bone to work with, Grellet-Tinner and Codrea (2014) suggested the T. sebesensis crest anchored muscles to form a ‘sizeable fleshy crest’, acted as a rudder in flight, that it somehow highlighted co-evolution between Romanian pterosaurs and angiosperms, and ecological segregation between azhdarchids and thalassodromids. All of these ideas are pretty radical in one way or another, especially considering the fossil material they are based on.

Blah blah blah… extraordinary claims, extraordinary evidence etc. When T. sebesensis was published it raised the collective eyebrows of pterosaur workers for all the wrong reasons. ODA-28 has no obvious ties to Thalassodromidae (or Thalassodrominae, if that’s how you roll - see Witton 2009), Pterosauria, or even to a cranial crest. Today, I and 19(!) other authors have said this in print (Dyke et al. 2014), noting that ODA-28 lacks any pterosaurian synapomorphies or even features typical of the group. As anyone who has handled pterosaur fossils can attest, pterosaur remains are distinctive at gross and microscopic level, and ODA-28 lacks any features expected in pterosaur bone (e.g. extremely thin bone walls separated by trabeculae). Any resemblance to the Thalassodromeus sethi holotype is entirely superficial, and shared characters between the two specimens - notably the ‘fossae’ at the base of the ‘T. sebesensis’ crest - are really incomparable on detailed examination. A clear lack of symmetry in ODA-28 shows it is not a medial skeletal element either, and thus not the cranial crest of anything. In short, cancel the text-book revisions: the temporal and palaeobiogeographical anomaly of ‘Thalassodromeus sebesensis’ is just a fairly major misidentification of a scrappy fossil (Dyke et al. 2014).

The 'flying turtle': the holotype of 'T. sebesensis' compared with the plastron of the turtle Kallokibotion. A, NHMUK R4930, the lectotype plastron of Kallokibotion magnificum with the portion corresponding to ODA-28 outlined in black (photo supplied by S. Chapman, Natural History Museum, London); B) ODA-28 (modified from Grellet-Tinner and Codrea, 2014). Abbreviations: hypo, hypoplastron; hxc, hypoplastron-xiphiplastron suture; ihc, intra-hypoplastral suture; ib, inguinal buttress; ps, pubic scar; meso, mesoplastron; mhc, meso-hypoplastral contact; pll, posterolateral lip; xiphi, xiphiplastron. Scale bar for A equals 50 mm. From Dyke et al. (2014).

Is ODA-28 anything exciting at all? Well, not especially. The specimen is clearly a piece of turtle plastron, exactly matching the internal structure of the hypoplastron and xiphiplastron of the Maastrichtian, Romanian genus Kallokibotion (above, Dyke et al. 2014). The anatomy of Kallokibotion has been documented fairly thoroughly and known for about 100 years (e.g. Gaffney and Maylan 1992), allowing us to be confident in this identification. Ergo, 'T. sebesensis’ offers nothing other than new a piece of fossil turtle and a name for the Kallokibotion synonymy list.

In all, a bit of an anticlimax. How did our short paper end up with 20 authors? The response was started by experts in the terrestrial faunas of upper Cretaceous Romania, who asked me and the Natural History Museum’s Lorna Steel if we could contribute a few paragraphs targeting the flawed pterosaur identity of the specimen. While we were working, it emerged that pterosaur experts from Brazil were also planning a response. The editors of Gondwanan Research, who published Grellet-Tinner and Codrea (2014), understandably only wanted one response, so the two teams joined forces. By the time experts in turtles, Romanian fossils and pterosaurs were all on board, we ended up with a truly international background: the USA, UK, Brazil, Romania and France are all represented.

A final note: this is not the first time thalassodromids have been pulled to the top of the Cretaceous. Kellner (2004) and Martill and Naish (2006) argued that a partial skull and mandible from the Maastrichtian Javelina Formation of Texas represented a thalassodromid based on perceived similarities with the thalassodromid Tupuxuara. While others have argued against this idea (the mandible and premaxillary morphology are more similar to those of azhdarchids - Lü et al. 2008; Witton 2013) - these claims have not been met with a sledgehammer response because the suggestions are not unreasonable. Sure, I don’t think the Javelina material in question is thalassodromid, but I can see why others might. ‘T. sebesensis’ has been swiftly rebutted by a crowd of experts because the underlying science is so clearly bogus that all concerned with pterosaur and Romanian palaeontology wanted it’s impact nipped in the bud. A response from Grellet-Tinner and Codrea will be published soon, so we'll see what they make of our rebuttal. To end on a high: there are exciting pterosaur remains coming out of Romania, and some of them are in the review/publication system already. Hopefully, we'll have some news on these out soon.

References

  • Dyke, G. J., Vremir, M., Brusatte, S., Bever, G., Buffetaut, E., Chapman, S., Csiki-Sava, Z, Kellner, A. W. A., Martin, E, Naish, D, Norell, M, Ősi, A, Pinheiro, F. L., Prondvai, E, Rabi, M, Rodrigues, T., Steel, L., Tong, H, Vila Nova B. C. & Witton, M. (2014). Thalassodromeus sebesensis-a new name for an old turtle. Comment on" Thalassodromeus sebesensis, an out of place and out of time Gondwanan tapejarid pterosaur", Grellet-Tinner and Codrea. Gondwana Research. IN PRESS.
  • Gaffney, E. S., & Meylan, P. A. (1992). The Transylvanian turtle, Kallokibotion, a primitive cryptodire of Cretaceous Age. American Museum novitates; no. 3040.
  • Grellet-Tinner, G., & Codrea, V. A. (2014). Thalassodromeus sebesensis, an out of place and out of time Gondwanan tapejarid pterosaur. Gondwana Research.
  • Kellner, A. W. A. (2004). New information on the Tapejaridae (Pterosauria, Pterodactyloidea) and discussion of the relationships of this clade. Ameghiniana, 41, 521-534.
  • Lü, J., Unwin, D. M., Xu, L., & Zhang, X. (2008). A new azhdarchoid pterosaur from the Lower Cretaceous of China and its implications for pterosaur phylogeny and evolution. Naturwissenschaften, 95(9), 891-897.
  • Martill, D. M., & Naish, D. (2006). Cranial crest development in the azhdarchoid pterosaur Tupuxuara, with a review of the genus and tapejarid monophyly. Palaeontology, 49(4), 925-941.
  • Witton, M. P. (2009). A new species of Tupuxuara (Thalassodromidae, Azhdarchoidea) from the Lower Cretaceous Santana Formation of Brazil, with a note on the nomenclature of Thalassodromidae. Cretaceous Research, 30(5), 1293-1300.
  • Witton, M. P. (2013). Pterosaurs: natural history, evolution, anatomy. Princeton University Press.

Friday, 25 July 2014

"Think Batman x Iron Man": how pterosaurs are inspiring the next generation of aircraft

Admit it, whatever you drive to work seems a little less adequate now.

Pterosaurophile Mike Habib was recently featured in a Scientific American article about the utility of pterosaur research. Let's face it, as cool as pterosaurs are, it can be hard to justify research into them when the world is faced with real problems like climate change, overpopulation, an enormous biodiversity crisis and Michael Bay movies. But Mike's interest in pterosaurs principally concerns biomechanics, quantifying the mechanical properties of pterosaur anatomy and seeing what it was capable of, and this sometimes allows transference of their evolutionary solutions to our own technological problems. Among other things, pterosaur biomechanics might be applied to some big projects: developing unmanned vehicles - including some which may explore other planets - and developing wind-stable fabrics. The latter may not sound very exciting, but wind-resistant fabrics are essential in all sorts of extreme activities, from exploring remote corners of the world (think tents), lightweight aircraft (parachutes, hang gliders, etc.) and extreme sports (wingsuits).

But that's small fry compared to one idea mentioned in the article. As part of an international team - including myself - pterosaurs may be launching air travel in a whole new direction. The manner in which pterosaurs took off - so called quadrupedal launch - offers a solution to a problem faced thousands of times around the globe each day: launching aircraft into the air as effectively as possible. As we all know, three lines of evidence point to pterosaurs launching quadrupedally, with most effort coming from their forelimbs. 1) animals launch using from their 'default' gait, and pterosaurs were quadrupeds; 2) pterosaur forelimbs are much more developed than their hindlimbs, whereas the opposite is true in hindlimb launchers and, 3) above a certain size, pterosaur hindlimb bones would actually fail in launch (Habib 2008, 2013; Witton and Habib 2010). These point to a powerful, quadrupdal launch mechanic which permitted even the largest, 200-250kg pterosaurs to take to the skies from a standing start, while birds - with their hindlimb launches - are seemingly capped at 70-80kg.

It's not only large birds which look enviously on pterosaurs. Most of our own aircraft require runways for takeoff. Vehicles which can take off without runways, like helicopters, are constrained to large size because of their power requirements and required wingspans. All aircraft launches require lots of fuel, and lots of space. It's unsurprising, then, that quad-launching giant pterosaurs have attracted the attention of engineers, as they clearly evolved a method of launch which is not only space and fuel-efficient, but also incredibly powerful. Practical results are undoubtedly years away, but the notion of a small, solo-pilot aircraft being capable of quad-launch and powered flight is realistic enough that we're seeking money for a project to test the waters. The concept we have in mind resembles a suit more than a plane - as Mike put it on Twitter, "think Batman x Iron Man" - alluding to concepts of the craft being controlled by a person strapped within the chassis, sort of like wearing a multi-million dollar pterosaur costume.

A visual history of pterosaur-inspired flying machines. 1, Ernst Stromer, 1913, basic glider model of Rhamphorhynchus wing membranes; 2, Hankin and Watson, 1914, a model based on their pioneering studies of Pteranodon flight (Hankin and Watson 1914); 3, Erich von Holst, 1957, a rubber band powered, wing flapping Rhamphorhynchus glider; 4, Cherrie Bramwell and George Whitfield, 1974, 7m wingspan Pteranodon glider based on their seminal 1974 paper; 5, Bramwell and Whitfield, 1984, half scale 4.5m wingspan Pteranodon made for the BBC; 6, Paul MacReady, 1984-85, 5 m span Quetzalcoatlus remote controlled, computer balanced glider (see MacCready 1985); 7, Margot Gerritsen, 2005, scaled Anhanguera with fully articulated wings built for National Geographic; 8, Matt Wilkinson, Rodger Highfield, and Vivian Bock, 2007, wind tunnel model of Anhanguera used to test Wilkinson’s hypotheses on pteroid orientation, 9, PteroFlight, our new project looking into pterosaur wing performance and its applications. Image compiled by Iain McCreary, used with permission.

What might such a thing look like? Sadly, it's not going to look like the thing at the top of this post. What you've got there is food for thought rendered by someone who's aircraft design skills boils down to watching science fiction movies, and who's engineering protocols are determined by Cool Points. It takes the idea of a 'pterosaur exoskeleton' to an extreme definition, right down to the limb proportions, wing folding and ability to walk about on all fours. Undeniably cool looking, just not very practical. But technologies and ideas taken to an extreme in this painting actually do exist. Augmentation of human frames with robotic exoskeletons is an intensive area of research and already employed to aid physically disabled people, as well as boosting the carrying strength of ground troops. Computers capable of flying deliberately unstable and responsive aircraft -manned or unmanned - are widely utilised. Large, controllable pterosaur-inspired vehicles with moving, adaptable wings have been researched for 100 years (above) and achieved flight (albeit not launch) on numerous occasions, with recent models featuring automatic computer control. The basic elements of this project - essentially a computer-supported, pterosaur-inspired lightweight flying exoskeleton - are at the far end of known technological spectra, not fantasy and hokum.

Of course, we're not going to see pterosaur-inspired suits catapulting people skywards tomorrow. Some serious research and developmental work is required before we see anything like a working concept or even - if we're honest - if it's possible at all. At this stage, however, this ultimate application of pterosaur research is not being ruled out. In other words, keep watching the skies - and check out Mike's Scientific American feature for more details.

References

  • Bramwell, C. D., & Whitfield, G. R. (1974). Biomechanics of PteranodonPhilosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 503-581.
  • Habib, M. B. (2008). Comparative evidence for quadrupedal launch in pterosaurs. Zitteliana, 159-166.
  • Habib, M. (2013). Constraining the air giants: limits on size in flying animals as an example of constraint-based biomechanical theories of form. Biological Theory8(3), 245-252.
  • Hankin, E. H., & Watson, D. M. S. (1914). On the flight of pterodactyls. Aeronautical journal, 324-335.
  • MacCready Jr, P. B. (1985). The great pterodactyl project. Engineering and Science49(2), 18-24.
  • Witton, M. P., & Habib, M. B. (2010). On the size and flight diversity of giant pterosaurs, the use of birds as pterosaur analogues and comments on pterosaur flightlessness. PloS one5(11), e13982.

Thursday, 17 July 2014

TetZooCon 2014: the event the palaeozoological blogosphere deserves


Last Saturday hosted an event which might, in future years, be considered a strange experiment. Set up in typical convention manner with attendance fees, invited talks and interactive audience activities, its unique selling point was its inspiration: a (largely) technical science blog which covers obscure animals in as much, often more, detail than you'll find in any textbook or scientific paper, as well as arcane topics such as speculative biology, natural history art memes, and cryptozoology. I'm talking, of course, of TetZooCon 2014.

NB. Like a chump, I didn't take a single photograph the entire day, so you'll have to make do with a very bland blog post.

Held at the London Wetland Centre on the 12th of July, TetZooCon 2014 was the latest expansion of the 'TetZooVerse', an internet enterprise founded on three incarnations of the Tetrapod Zoology blog and, more recently, a podcast, two internet comics and on-demand merchandise. The brainchild of Darren Naish and (more recently) John Conway, it's undoubtedly one of the longest running and most successful science outreach exercises on the internet, and notable for covering complex narratives and scientific problems in the world of tetrapod studies. TetZoo fans thus comprise not only casual internet surfers but also researchers and practising scientists. Few other blogs can boast such appeal and far reach, making TetZoo one of the few internet enterprises which might manage the tricky move from the 'free' virtual world to one of admission fees, travel expenses and conference overheads.

In many respects, TetZooCon almost felt like watching a live version of the blog as different talks - essentially 'live blog posts' - covered an array of TetZoo-relevant topics. Unlike TetZoo, the floor did not solely belong to Darren and John, but shared by a host of excellent speakers. I'm not going to cover the talks in detail here because others have already done so, but the topics included speculative zoology, amphibian conservation, wildlife photography, vertebrate palaeontology, crytozoology and mythical animals. Regular readers will know that I was among the invited speakers and covered changing perceptions of azhdarchid pterosaurs. As with other elements of the TetZooverse, these talks meandered from pure science (sauropod neck length) to almost humanist topics (mermaids, the cryptozoological leanings of Shakespeare). Many struck ground between these extremes, noting the interplay between science and culture and how they've influenced each other - for better and worse. Arguably, providing a platform for such talks and the diversity of topics was TetZooCon's greatest success. I've not been to a conference where talk topics varied so considerably and, in contrast to conferences with homogenous themes, there was no chance for getting subject-weary here. The talks were presented at pitch-perfect semi-technical level, assuming that the audience was intelligent and would have some prior knowledge of the broader subjects at hand (e.g. there were no, or only very brief, explanations for what things like Orang Pendek, sauropods or azhdarchid pterosaurs are), while also appreciating the room was not full of experts. It helped, of course, that the speakers and presentations were excellent. I definitely walked away with a greater education than I walked in with.

Other events included a palaeoart workshop, where attendees - led by palaeoartists John Conway, Bob Nicholls and, er, me - attempted to restore the life appearance of the historic 'Mantell Piece' Mantellisaurus fossil, and a TetZoo-themed quiz. The former was of interest for not only palaeoart aficionados, but also anyone wanting to know how fossils are interpreted. There was discussion over bone identification, how many individuals were represented by the specimen, how we could deduce the affinities of the animal and so-on, and we all compared images and notes at the end. The work of the lead artists was beamed onto the screen behind us so audience members could not only see what we were sketching, but engage in discussion with us about specifics of the fossil. Suffice to say (cheating ne'er-do-wells aside who recognised the specimen and simply drew an ornithopod), there was virtually no reconstruction consensus. Tours of the wetland centre and the obligatory pub dinner followed, while merchandise - including prints, 'official' TetZoo products and the much lauded Palaeoplushies - was on sale all day.

Was the event a success? As a speaker and delegate, my opinion is an unreserved 'yes'. There were enough delegates to generate that 'real' conference feel, the day was varied and interesting, and it was a lot of fun to be part of. With strict scheduling, custom 'palaeoart cams', delegation packs and almost flawless audiovisual performance (except for my own talk!), the day was pulled off with the sort of professionalism you'd expect from a long running conference rather than a first-time event. Most importantly, the day felt fresh and different from other conferences. As millions of TetZoo readers and listeners attest, there is a large audience for the 'offshoots' of zoological science such as palaeoart, speculative zoology and so-on, but few venues exist to chat about these topics outside of the internet. TetZooCon is a welcome plug in that gap.

Of course, whether we'll see a second TetZooCon depends on the transformation of online (and free) participation in the TetZooverse to financial and time commitments from potential delegates. This point is really why I wanted to write this short post. Turnout for this first event was good and, happily, conference overheads were recouped. At the same time, I don't think Darren and John slept in beds of gold leaves that evening. Events like these live and die on the whims of potential delegates so, if you were 50:50 about attending this time around and decided against it, rest assured that it was a blast and you won't want to miss out again. If the event passed you by entirely, but you like the idea of an annual celebration of the palaeontological and zoological blogospheres, then you'll also want to get on board next time around. This is a conference with lots of potential and, with enough support, it could become one of the most accessible, unique and interesting fixtures of the conference calendar. If it happens, I'll be booking my place for TetZooCon 2015 as soon as I can next year. If that's not high recommendation, I don't know what is.

Monday, 30 June 2014

Azhdarchid pterosaurs vs. the world

Azhdarchids: also available in flying. Depicted animal here is based on Quetzalcoatlus sp., but no taxon in particular.
In just a few weeks the world will stop for TetZooCon, a one day convention of all things we associate with the famous Tetrapod Zoology blog and podcast - tetrapods real and scientifically-speculative from wondrous, charismatic fossil reptiles to deceptively interesting small, brown herpetofauna. If you’re reading this, you’re slap bang in the middle of the TetZoo demographic and I guarantee* you’ll have a good time. Tickets are available until Friday 4th July, and it’s all going down one week later - Saturday 12th. Get your place while you can, or forever live with the shame.

*Guarantee not guaranteed.

In a surprise move, my contribution to TetZooCon features pterosaurs. Specifically, I’m looking at the way one group of pterosaurs has made major ripples in the palaeontology pond in recent years - and not just scientifically. The changing face of pterosaur science is certainly interesting, but an equally intriguing, rarely told story exists on the popular face of flying reptile research. To whet your appetite, here’s an 'extended abstract' of my TetZooCon talk, giving some insight into what we'll be talking about in a couple of weeks.

PteroPop

Pterosaurs are not unfamiliar characters in popular culture. They have been mainstays of science fiction literature since at least 1874 (Jules Verne’s Journey to the Centre of the Earth), made the jump to the silver screen in 1925 (The Lost World), and since starred in uncountable stories of time-travel, lost worlds and Jurassic Park-inspired de-extinction fiction. Neither are they strangers to public education, from being part of Benjamin Waterhouse Hawkins’ 1854 Crystal Palace menagerie to modern appearances in £multi-million documentaries. The hundreds of years of popular pterosaurs have rarely showed much adherence to flying reptile science: their appearances, behaviours and lifestyles mostly reflect a shorebird-like 'pterosaur archetype' rather than the specific anatomy and habits of a once-living taxon.

One of the many curious things about early azhdarchid reconstructions is the head nubbin - a short, posteriorly-directed conical(?) crest on the back of the head. There is nothing like this known from any azhdarchid. Far from being an early mistake, reconstructions with head nubbins persist until at least 2000. Slide from my TetZooCon talk.
But all that is changing. One pterosaur lineage has overshadowed ‘generic’ popular pterosaurs to bring aspects of ‘real’ pterosaurology to the masses, and has even stolen some limelight from dinosaur celebrities in the process. Media as disparate as documentaries and comic books show these animals in (basically) anatomically correct forms, with accurate but atypical postures, and behaviours which are far removed from the idea of pterosaurs being ancient seabird analogues. The animals in question are, of course, the long-necked, toothless and gigantic flying reptiles, Azhdarchidae.

In some respects, the recent surge of azhdarchid pop-culture uptake is a bit strange. It is not, for instance, that azhdarchids are a newly discovered group. Far from it, their fossils were found by at least the latest 1930s or early 1940s; good remains were apparent the 1970s, and the concept of Azhdarchidae was formalised in the early 1980s. They’re not new to popular culture either, having hung around its periphery since the 1970s to be wheeled out as 'Largest Flying Animals Ever' on occasion. These early popular azhdarchids showed little uniformity in their reconstruction - maybe even less than other pterosaurs at that time. Most bore little resemblance to actual azhdarchid fossils, either anatomically of functionally (above): hugely elongate wings, longirostrine skulls with snub-noses, pin-heads, toothed jaws, short-necks, long necks with swan-like flexibility were all rendered in artwork from 1970 - 1990. Art produced in the 1980s - 2D work by Greg Paul, Paul MacCready’s 1985 glider (below), and a (largely sculpted) azhdarchid skeleton mounted by the Texas Memorial Museum - were probably the first works to strike close to reality, but they’re still a bit short of the mark. John Sibbick’s better known and more influential 1991 snub-nosed Quetzalcoatlus was a step back from these more accurate works, accidentally making a chimeric azhdarchid from at least two Javelina Formation azhdarchids (this ‘snub nose’ almost certainly belongs to an unnamed, short-skulled azhdarchid from the same horizon as Quetzalcoatlus).

The famous 1985 'QN' pterosaur, a half-size gliding Quetzalcoatlus northropi and friends, including its designer, the late Paul MacCready (right of middle, in the tie). The model flew successfully multiple times and isn't a bad rendition of an azhdarchid, although many assumptions made in its construction conflict with modern pterosaurology. From MacCready (1985).
Why all the confusion over azhdarchid appearance? Most azhdarchid material known until the late 1990s was either too scrappy to inform artists about life appearance, while the more complete material (the small Quetzalcoatlus species) was infamously not published (still isn't!). The world at large was therefore not able to appreciate azhdarchid anatomy, so any artwork of them required more guesswork than usual. In some cases, entire 'reconstructions' were products of imagination. Not aiding the murky early phase of azhdarchid palaeoart was the transforming nature of pterosaur science which, in the 1980s and 90s, saw much of what we thought we knew about these animals turned on its head. Thus, artists who wanted answers to simple questions like standing postures, wing membrane attachment and so forth weren't always presented with straight answers. 1997 saw a potential change for the better when Unwin and Lü (1997) reclassified the Chinese Maastrichtian ‘nyctosaurid’ Zhejiangopterus linhaiensis as an azhdarchid, but few paid attention to this obscure species when reconstructing 90s azhdarchids, and artwork continued to remain of variable accuracy. The azhdarchid fossil record has not improved fantastically since 1997, only expanding via isolated, scrappy bits and pieces. Their sudden popularity and uniformity of reconstruction has nothing to do with a significantly improved azhdarchid fossil record, then.

Azhdarchids: over 40 Megafonzies of cool!

So, if azhdarchids aren’t new, and they’ve not sent a burst of insightful fossil material our way, why are they now so popular? Perhaps recent reappraisals of their appearance and behaviour have more influence here than anything else. Reconsideration of azhdarchid mass estimates (e.g. Paul 2002; Witton 2008; Henderson 2010; Sato et al. 2010), re-interpretations of lifestyles (Hwang et al. 2002; Witton and Naish 2008, 2013; Carroll et al. 2013) and flight characteristics (Habib 2008, 2013; Witton and Habib 2010) have recast azhdarchids from billboards of flighted animal size to muscular, terrestrially-competent predators and powerful fliers which were also giant. This has seen azhdarchids landing ‘major roles’ in palaeo pop media. In the last five years, erect-limbed, terrestrially stalking and quad-launching azhdarchids featuring in the BBC documentary Planet Dinosaur, Atlantic Productions’ Flying Monsters 3D, the 20th Century Fox film Walking with Dinosaurs 3D, the 20,000AD comic series Flesh and recent comics of Teenage Mutant Ninja Turtles, been made into at least two figurines by CollectA, in the upcoming, Steam-released multiplayer game The Stomping Land, in Nathan Carroll's wearable pedagogic puppet form and even a rap. This uptake of the same pterosaur lineage is all the more surprising when you consider the diversity of influences and goals of these projects, as well as the near-infinite sea of fossil species which could take their place. More remarkably, these depictions of azhdarchids aren’t anatomically bad or variable, either: they have large, pointy heads with posteriorly placed crests, long necks, short wing fingers and long limbs. It seems azhdarchids have genuinely penetrated the pop-palaeo zeitgeist.

Azhdarchids in recent comic books, including Teenage Mutant Ninja Turtles and the fabulous 20,000AD series Flesh. Note the far right panel - terrestrially stalked TO DEATH!!! Awesome stuff - should really cover Flesh in more detail here some time. Slide from my TetZooCon talk.


The times, they are becoming very different

I think there's several points of interest here. Firstly, we seem to be witnessing a relative rarity within palaeo pop culture: the rapid indoctrination of a new lineage into the canon. What takes a fossil species from an occasional extra and bit-part player to relative superstardom in the space of a few years? There must be aspects of ‘new’ azhdarchids which have suddenly made them marketable and appealing, and very quickly following a spate of new research. Before anyone mentions it, I can vouch for azhdarchid uptake not being overtly pushed by the scientists involved in reinventing them. I've acted as a consultant for three of the projects listed above because ‘new’ azhdarchids were sought after by the media producers, and not as a generic pterosaur expert who pushed his own ideas. The other media, as far as I'm aware, just moved forward with these ideas on their own. 

There is doubtless a myriad of factors making azhdarchids popular - good publicity, a sudden glut of tv and movie interest in prehistoric animals etc. - but I suspect the most important factor is that science accidentally gave azhdarchids a more appealing ‘character’. When we restore fossil animals in art and science we cannot help but impose certain ‘character traits’ into them, and, as with fictitious characters, those with traits we consider desirable are more likely to be popular. 'New' azhdarchids embody everything which is classically cool: they’re original; imagined as assertive, confident animals of great skill and energy; undoubtedly stylish and unusual to behold; instantly recognisable, and their large size creates a cool sense of indifference -metaphorically and physically bigger than us and our problems. Plus, they have that edge of danger: big, predatory species which harvest smaller ones for their own use: bad guys and anti-heroes are always cooler than the good guys. In short, it’s not surprising that ‘new’ azhdarchids are popular because they embody the same characteristics as most iconic literary monsters. The traits outlined above could easily apply to H. G. Wells’ Martian tripods (below) or the Star Wars mechanical walkers. Prior to their reinvention, azhdarchids didn’t - and couldn’t - have this appeal, as their appearance was ill-defined, their lifestyles too poorly constrained (skim-feeding? sediment probing? aerial hawking? aquatic pursuit predation? wading?), and much of our science pointed to rather ineffective, flimsy animals. This not only prevented crystallisation of an appealing and memorable palaeo pop ‘character’, but also didn't give them much popular clout.  

The uptake of azhdarchids in pop-culture may reflect their recent recasting as stylish, dominating predators of small, defenceless animals, a formula known to strike a nerve with the public - ask H. G. Wells. Do our palaeo pop-culture icons attain iconic status because, like some literary ones, they simply evoke cool characteristics and styles? 
Perhaps more importantly, azhdarchids have - for what seems like the first time - persuaded popular culture to widely depict actual pterosaurs rather than an anonymous set of wing membranes and toothy jaws. That's pretty neat, as it means we're starting to break the notion that different pterosaurs are just minor variants on the same basic animal. I wonder if this applies to pterosaur science too, as research into azhdarchid lifestyles and habits is providing compelling evidence of palaeoecological variation within the group: shorebird, fish-eating habits applied almost universally to Pterosauria just doesn't work for these guys. With it being increasingly obvious that azhdarchids were doing their own thing, it's easier to start seeing other pterosaurs as potentially having distinctive lifestyles as well. Azhdarchids may be the thin end of the wedge in this respect for both popular and scientific circles.

Of course, no-one can predict how long our current interest in azhdarchids will last, nor what will happen to hypotheses concerning terrestrial stalking, quad-launch and so on. My gut feeling is that these ideas will stand up to scrutiny, but we can never predict what the fossil record or new studies will tell us. Whatever happens, these ideas and the animals they concern have gone some way to superseding generic ‘pterodactyls’ in palaeontological culture, replacing them with a more accurate and detailed appreciation of pterosaur diversity. But what next for azhdarchids? What advances in azhdarchid science are on the horizon? How might these impact their portrayal in popular culture? For that, you’ll have to attend TetZooCon and my talk. Tickets!

References

  • Carroll, N. R., Poust, A. W. & Varricchio, D. J. (2013). A third azhdarchid pterosaur from the Two Medicine Formation (Campanian) of Montana. In: Sayão, J. M., Costa, F. R., Bantim, R. A. M. And Kellner, A. W. A. International Symposium on Pterosaurs, Rio Ptero 2013, Short Communications. Universidad Federal do Rio de Janeiro: pp 40-42. 
  • Habib, M. B. (2008). Comparative evidence for quadrupedal launch in pterosaurs. Zitteliana, 159-166.
  • Habib, M. (2013). Constraining the air giants: limits on size in flying animals as an example of constraint-based biomechanical theories of form. Biological Theory, 8(3), 245-252.
  • Henderson, D. M. (2010). Pterosaur body mass estimates from three-dimensional mathematical slicing. Journal of Vertebrate Paleontology, 30(3), 768-785.
  • Hwang, K. G., Huh, M., Lockley, M. G., Unwin, D. M., & Wright, J. L. (2002). New pterosaur tracks (Pteraichnidae) from the Late Cretaceous Uhangri Formation, southwestern Korea. Geological Magazine, 139(04), 421-435.
  • MacCready Jr, P. B. (1985). The great pterodactyl project. Engineering and Science, 49(2), 18-24.
  • Paul, G. S. (2002). Dinosaurs of the air: the evolution and loss of flight in dinosaurs and birds. JHU Press.
  • Sato, K., Sakamoto, K. Q., Watanuki, Y., Takahashi, A., Katsumata, N., Bost, C. A., & Weimerskirch, H. (2009). Scaling of soaring seabirds and implications for flight abilities of giant pterosaurs. PloS one, 4(4), e5400.
  • Unwin, D. M., & Lü, J. C. (1997). On Zhejiangopterus and the relationships of pterodactyloid pterosaurs. Historical Biology, 12(3-4), 199-210.
  • Witton, M. P. (2008). A new approach to determining pterosaur body mass and its implications for pterosaur flight. Zitteliana, 143-158.
  • Witton, M. P., & Habib, M. B. (2010). On the size and flight diversity of giant pterosaurs, the use of birds as pterosaur analogues and comments on pterosaur flightlessness. PloS one, 5(11), e13982.
  • Witton, M. P., & Naish, D. (2008). A reappraisal of azhdarchid pterosaur functional morphology and paleoecology. PLoS One, 3(5), e2271.
  • Witton, M. P., & Naish, D. (2013). Azhdarchid pterosaurs: water-trawling pelican mimics or "terrestrial stalkers"?. Acta Palaeontologica Polonica doi: http://dx. doi. org/10.4202/app, 5.