Wednesday 28 January 2015

Bonus pterosaur (anurognathid) art you've never seen before! (sort of)

Anurognathus ammoni makes itself like a tree, but doesn't leave. Prints are available.
Last week I unceremoniously dumped several revamped pterosaur images on the blog after they were prepared for a talk on one of my favourite topics - pterosaur functional morphology and biomechanics. Turned out that I wasn't quite done tinkering with old images however, because another piece - above - was set for 11th hour reworking. It shows one of the subject taxa of my talk - an anurognathid pterosaur - hunched up and perched in a tree, its cryptic colouration helping it to blend in somewhat with the underlying branch. The original version can be found in my book, with this newer variant merely adding more detail, depth and a bit of background.

This depiction of anurognathid palaeobiology isn't merely idle speculation on my part. In 2007, pterosaurologist Chris Bennett described a famously spectacular, tiny specimen of Anurognathus from the Jurassic of Germany preserved with its limbs and wing fingers folded around its body. Chris noted that this posture is common in anurognathid fossils but largely unseen in other pterosaurs, and suggested it reflected a common in vivo limb configuration specific to this group. He further speculated that the purpose of this pose was to make the animals compact and inconspicuous, for which cryptic colouring would also be beneficial. There are obvious parallels to make here with insect-chasing birds like nightjars and potoos, which also rely on specific postures and colouration to blend into their surroundings. This is not merely to avoid detection by predators, but also gives an advantage for ambushing prey. Given that anurognathids are widely considered insect-chasers, the surprising difficulty associated with catching some insect prey and the explosive flight ability of these little pterosaurs (stay tuned!), Bennett's speculations about their appearance and habits fit neatly into current models of anurognathid palaeobiology, and can be considered a reasonable way to depict these animals in palaeoart.

Coming soon - hopefully - a host of theropods, more pterosaurs, and the most exciting dinosaur art of all... a solitary hadrosaur!

Reference


  • Bennett, S. C. (2007). A second specimen of the pterosaur Anurognathus ammoni. Paläontologische Zeitschrift, 81(4), 376-398.

Tuesday 20 January 2015

Pterosaur art you've never seen before! (sort of)

Later this week I’m travelling to the Netherlands to give a talk on pterosaurs at the Museon, The Hague. I’ll be part of a series of public talks on Mesozoic reptile lifestyles celebrating the opening of the Museon's new Dino Jaws exhibition, and it should be a blast. I’ve revisited some of my older pterosaur paintings to add more detail and depth when featuring them in my talk, and thought I’d share the results here. Some of these images aren’t that old really, but, thanks to beefing up my painting rig before Christmas, I find some of my work from even a few months ago can look a lot nicer with just a few hours work. As usual, prints are available of all images shown below.

Arambourgiania: remaining huge in artwork since 2013. See this page for the original.
First up is a tweaked version of my 2013 Arambourgiania, a giraffe, and a standard wife-unit scale bar. There’s not much to say here – I just wanted to put more detail into the pterosaur so it looks better in a close-up panning presentation animation. At some point, hopefully soon, a version of this image featuring two azhdarchids will be published.

An azhdarchid in high-altitude, long distance flight. Original here.
Second, the flying azhdarchid which made a debut at TetZooCon last year. I felt the initial image was a bit flat, so this has more depth added to the background. The depicted animal is a ‘generic’ azhdarchid, although obviously similar to the smaller Quetzalcoatlus species. It’s shown flying rather high – many thousands of feet in the air – on a long-distance flight. Mike Habib and I have droned on about the awesome flight capability of giant azhdarchids for years, and we expect the range and flight speed of smaller azhdarchids – with, say, 5 m wingspans – to be relatively impressive too. They may not have been capable of booming around the planet with the same gusto as their giant cousins, but continent hopping was certainly not beyond them.

The anurognathid Anurognathus ammoni, brought to you by evolutionary processes which wanted Muppets to rule the skies. 
The third reworking shows a species at the other end of the pterosaur size spectrum, the diminutive Anurognathus ammoni. Some readers may recognise this painting from my book. Anurognathids haven’t been covered in much detail at this blog, but that will likely change soon when Mike Habib and I publish a new study on their functional morphology in the near future. This painting alludes to something which we attempt to quantify in that study – prey size. Anurognathids are frequently depicted as hawking relatively large insects like dragonflies, but – based on prey proportions in modern avian insect hawkers, and the delicate build of anurognathid skulls – much smaller insects were probably pursued instead. Catching aerial insects is already difficult enough, so why chase relatively rare, enormous and feisty prey when abundant small midges can be scooped out of the sky with relatively little effort? Because anurognathids aren't big beasts - wingspans of less than 0.5 m are common - their likely prey was probably best measured in millimetres, as shown by the Target Midge in this picture. Other features to note in this painting include the tufted wing tips and completely fuzzy face, both of which are known from fossils and, for the time being at least, unique to anurognathids. The ‘cryptic’ colouration and nocturnality are nods to recent work on these pterosaurs suggesting these pterosaurs were shy, well-hidden creatures which were primarily active at dawn and dusk. More on these neat pterosaurs as time – and manuscript progress – permits.

To finish – because I can’t not post this – here’s a poster for the superhero movie the world deserves, but not the one it needs right now. Image by Jon Davies (@SovanJedi on Twitter – you may recall his equally excellent lampooning of in-your-face dinosaur art from last year).

That logo needs a T-shirt. Image manipulation by Jon Davies.

Monday 5 January 2015

Babified Allosaurus and prehistoric sphenodontians

A curious juvenile Allosaurus is told to get off the lawn owned by a grumpy Opisthias. Prints are available. 
With Christmas 2014 fading into memory, I can start sharing pieces of artwork commissioned for presents by various clients without fear of spoiling any surprises. I have several of these to reveal, and the first of which is above, showing an alsatian-sized Allosaurus and a feisty Jurassic sphenodontian, Opisthias. The Allosaurus in this image is based on one of the smallest Allosaurus specimens known, the partial skeleton SDSM 30510. This specimen, described by John Foster and Daniel Chure in 2006. is notable for not only its small size but also its proportions: it seems that very young Allosaurus had relatively longer legs than their parents, which is interpreted as them being more sprightly and cursorial than larger Allosaurus individuals (Foster and Chure 2006). I tried to capture these proportions accurately in the image, not the least because it was commissioned as a Christmas present for John Foster, the chap who discovered and assessed the significance of the specimen (I hear from my commissioner, ReBecca Hunt-Foster (@paleochick), that it's got the seal of approval). It must be stressed, however, that much of the reconstruction is speculative because many details of tiny Allosaurus anatomy remain unknown. Thus, a lot of the anatomy here reflects 'babification' of larger Allosaurus specimens. 

Allosaurus is joined in this image by the small sphenodontian Opisthias rarus. As with many small Mesozoic herps, Opisthias is not well known and much of what you see here as goes appearance and anatomy is based on the modern tuatara. It would be nice to know what Mesozoic sphenodonts really looked like rather than just trotting out variants of the Sphenodon bauplan again and again. Until better fossils are known, I guess this remains the most sensible option, however, as tired as it is. At least have good skull material for Opisthias and, from this, we can see it wasn't a straight replicate of the Sphenodon condition: the snout is longer, the temporal region rather shorter, and the teeth are generally more bulbous without pronounced anterior fangs. I attempted to further differentiate my Opisthias from Sphenodon with a green and red colour scheme, although its behaviour - an open mouth 'push up' pose - is a classic sphenodon threat display, a nod to the aggressive nature of modern male tuataras.

As is becoming tradition around these parts, I tweeted some in-progress images of this painting.




Coming soon: Deinonychus! The pterosaur formally known as 'Phobetor'! Comic-style Carnotaurus!

Reference


  • Foster, J. R., & Chure, D. J. (2006). Hindlimb allometry in the Late Jurassic theropod dinosaur Allosaurus, with comments on its abundance and distribution. New Mexico Museum of Natural History and Science Bulletin, 36, 119-122.