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Thursday, 29 November 2012

You've come a long way, baby


Way back at the end of 2009 I illustrated the image above, showing the size range of everyone's favourite rhamphorhynchine pterosaur, Rhamphorhynchus. This animal was first discoverd in the 1830s and is now represented by over 100 specimens, making it one of the best known pterosaurs, and probably the best known non-pterodactyloid pterosaur, of all. Being represented by specimens with wingspans ranging from 290 mm (in very young juveniles) to 1850 mm in large (probable) adults means that we have a better idea of Rhamphorhynchus growth allometries than we do for most pterosaurs (Bennett 1995; though also see Prondvai et al. 2012 for a contrary opinion), and this includes a detailed picture of the proportional changes taking place in the skull. These are the focus of this image here, which shows a portrait of a particularly tiny Rhamphorhynchus specimen with a 30 mm long skull (NHMUK R37012), alongside the biggest with its 192 mm skull length (NHMUK R38077). Unusually among reptiles, Rhamphorhynchus does not seem to gain more teeth with age, despite the elongation of its jaw presenting space for additional teeth. Instead, the teeth become more robust, transforming from fine, needle-like structures to relatively short, tusk-like forms. The shape of the mandible also becomes more pronounced with age, developing a curving, pointed keel. The  orbits - predictably - decrease in relative size, but adult Rhamphorhynchus retain proportionally large eye sockets even as adults, which probably hint at their predatory leanings.

This image was the first time I largely excluded showing details of the cranial fenestra in my reconstructed animals. They're still visible, but I recall making a very conscious decision to mute their appearance. Nowadays, my illustrations don't show them at all. Those interested in palaeoart will be aware that there is  currently a real push against the classic 'shrink-wrapped' appearance of animals in palaeoart, defying generations of artists who have applied minimal amounts of soft-tissue to their reconstructions to show their osteological details (check out Matt Wedel's festive plea for healthy-looking sauropods for an example. From this SV:POW! post). The observation that most skeletal anatomy is hidden behind soft-tissue is the rationale behind this movement, and it may be one of the most significant paradigm shifts to the palaeoart of Mesozoic and Palaeozoic reptiles since palaeontologists of the late 1960s and 1970s told artists to lift their dinosaur tails off the floor. More on this movement another time, perhaps: this is meant to be a word-light blog, after all.

References
  • 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.
  • Prondvai, E., Stein, K., Ősi, A. and Sander, M. P. 2012. Life history of Rhamphorhynchus inferred from bone histology and the diversity of pterosaurian growth strategies. PLoS ONE, 7, e31392.

Wednesday, 28 November 2012

Here goes nothing (redux)

It occurs to me that I don't really have much of an easily updatable, online home at present. My regular internet haunts aren't really suitable for rapid uploading lots of images or interacting with others. My Flickr site is too constrictive on comments and posting, and the Pterosaur.Net blog is a shared site that I don't want to clog with my garbage. Hence, I thought I'd set up a sister blog to my website, where I can post all the images I like, and you can comment all you like, without any hassle*. The objective here is to give myself an outlet for the paintings, ketches, diagrams and other media I've been making for the last few years, but rarely sees the light of day outside of its intended use and occasional posts on Facebook. My plan is to keep this rather straightforward by being word-light and picture-heavy, which should keep the post level up to at least one a week.

*For a few weeks, a version of this has been live at my website, but it communicated poorly with social network sites, so I've moved house to Blogger. Anyone who saw the old version of this post may be feeling a sense of deja vu, but new content will follow soon. Honest.

Admit it: you're thinking about doing this _right now_.

With that in mind, I'll leave this first opening post here. For the unitiated, the picture above is a full colour version of the opening image to a blog post, and now a full length lecture I recently gave at the University of Portsmouth, about speculative interactions between humans and pterosaurs, called 'Our Lives with Pterosaurs'. Just for fun, I've posted the poster used to advertise the talk below, too. I tried to capture some of the characteristic poster design common to Westerns made in the 50s and 60s, what with the wavy title and quotes from a critic (or Mike Taylor) and all. It's up to the viewer to decide whether the guy riding the azhdarchid is going to burst into 'The Deadwood Stage' from Calamity Jane as he soared away.

Anyway, enough nonsense. Were pterosaurs strong enough to carry humans to work throught the skies? Were they big enough to eat people? Head here, and to the follow up post here, to find out.