Saturday, February 04, 2006

The Walking With Dinosaurs ‘Micro-expression’

Two fantastic new theropod discoveries, reported in two different papers, made the news today, and it so happens that BBC News 24 wanted to do a piece on both of them. Curiously (and this is honestly nothing more than a coincidence), I acted as reviewer to both papers, so I’ve had the inside-info for some months. The papers are Dal Sasso et al.’s (2005) description of MSNM V4047, the whacking great big Spinosaurus snout that has been whispered about at conferences since the late 1990s at least, and Xing Xu et al.’s Nature article on Guanlong, a basal tyrannosauroid from the Upper Jurassic of the Junggar Basin, NW China. News on the latter was embargoed until 18-00 today, so I’m legally allowed to talk about it. Guanlong is known from two semi-complete specimens: they provide substantial new information on basal tyrannosauroids, but the most surprising thing is that the taxon possesses a large, bizarre, pneumatic mid-line cranial crest. For a (presumably) predatory dinosaur that attacked other animals with its mouth, this is an odd thing to evolve, to say the least. The obvious interpretation is that it’s a sexual display organ that exacted a heavy cost on its owner – ‘peacock’s tail syndrome’ as it’s known. As of right now (Wednesday night) the paper isn’t technically published, so it’s not cited below.

MSNM V4047 – Dal Sasso et al.’s new Spinosaurus – is significant both in terms of the new information it provides (we now know that the premaxilla in spinosaurines was, uniquely, not involved in forming the border of the external naris for example), and for its size. While the specimen is about 1 m long, it only represents that part of the skull rostral to the antorbital fenestra. Extrapolation based on more complete spinosaurid skulls indicates a total skull length of 1.75 m, and extrapolation based on good spinosaurid skeletons indicates a total length of 16-18 m. So, move over Tyrannosaurus (and Giganotosaurus for that matter): it’s official.. Spinosaurus is the biggest theropod. To be honest there’s been surprisingly little made of this in the media. Surely people should be up in arms about the dethroning of everyone’s favourite dinosaur?

So: the BBC interview. Unfortunately it was delayed by technical problems, then delayed some more. But we did it eventually. Guanlong was covered first, and I emphasised the fact that it was the first good Jurassic tyrannosauroid. We didn’t get round to mentioning the crest, or what this might mean. But I am told that the most amusing bit (Toni was texted by Jeff Liston on this point) concerns what happened as a clip from Walking With Dinosaurs was played. I’ll happily admit that I am not a fan of WWD: I really don’t like the way many of the animals were depicted, I don’t regard many of the behavioural speculations as useful or realistic, and on the whole I think they should have worked harder to include in the series what _is_ known about the palaeobiology of the relevant animals, rather than what might be extrapolated based on living animals (remind me to explain the ‘meerkat theory’ on this some time). Some of these criticisms were reflected in Naish and Mar... I mean Martill and Naish (2000), but most weren’t. Moving on, I am told that, when WWD was mentioned, I made some sort of hilarious grimace. I assumed this was a micro-expression, but apparently it wasn’t so micro. Oh well.

To prove how stupid I looked in the interview, Tone kindly took the above photo (I had to crop it strangely because of glare on the screen). So it’s all been the perfect end to a hectic day. I guess the blog on bear-eating pythons, Branston the picked turtle, and animals that die in trees will have to wait. As one colleague said to another, “I will reach through this phone line and strangle your lanky ass if I see any decrease in Darren's posting rate…. Blog on, dude, blog on”. And how did the British big cats talk go, I hear you ask? More on that later.

PS - for the latest news on Tetrapod Zoology do go here.

Refs - -

Dal Sasso, C., Maganuco, S., Buffetaut, E. & Mendezm M. A. 2005. New information on the skull of the enigmatic theropod Spinosaurus, with remarks on its size and affinities. Journal of Vertebrate Paleontology 25, 888-896.

Martill, D. M. & Naish, D. 2000. Walking With Dinosaurs: The Evidence. BBC Worldwide, London.


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