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Re: looking for illustration

I'm in quite close agreement with Mark. I don't see any way to restore the wings of either Quetz or Hatz at much more than 11 meters span (nor much less than that). The two animals are virtually identical in size, which makes me speculate that they may represent average adults. It seems to me that Arambourgiana cervical is probably from an individual roughly 10% smaller than the other two. My qualitative, unquantified hunch is that the absolute maximum span for a pterosaur built on the azhdarchoid bauplan is about 13 meters, and even then it would be pushing the azhdarchoid structure to the limit. Larger pterosaurs would have to have a major structural redesign. Mike may have looked into that maximum azhdarchoid sizing more than I have. Mike?

Re Matt Smith's full scale skeletal sculpture of Qn that can be seen on display at various museums, Wann and I worked pretty closely together on 'sizing' the missing items (the left wing is all Wann's, as is the shape of the skull -- which Matt based on my isometric dimensional blowup of one of Wann's early restorations of the Qsp skull). Any errors in all that scale-up sizing are mine, not Wann's or Matt's. Neither of us intended that those display sculptures be used for actual research, and I don't think Matt did either. As an example, the shape of the sculpture's scapulocoracoids is quite wrong. Which is my way of leading up to saying that in a 'real' Qn, I don't think the skull would be an isometric blow up of the Qsp skull -- I'd expect the relative width and height to be perhaps 15 or 20% more than we used, making the skull more robust, and I'd expect the length to be about the same as for Hatz, about 8 feet (we used 7 feet, which was an arbitrary number based on isometrically blowing the length of the Qsp skull up by a factor of 2.05 ). If we had not been in such a rush to make the TMM opening deadline, we'd have used allometric mods for the skull in some areas where we went isometric. We did use allometric blowups from Qsp in most of the animal's missing bits.

All that said, I don't have a personal opinion about whether these specimens represent the same or different species. I don't even have an opinion about whether Qn and Qsp are seperate species... :-)

----- Original Message ----- From: "Mark Witton" <Mark.Witton@port.ac.uk>
To: <jrccea@bellsouth.net>; <habib@jhmi.edu>
Cc: <dinosaur@usc.edu>
Sent: Sunday, August 02, 2009 4:03 AM
Subject: Re: looking for illustration

Yup, I agree. Frankly, it's almost surprising that we have any named giant azhdarchid taxa at all given that the material is so fragmentary and often represents poorly diagnosable skeletal components. I wonder if we should only really talk about 'generic' giant azhdarchids - as Mike and Jim point out, there's presently not enough overlapping material to make meaningful comparisons between forms. We can't say, for instance, that Hatzegopteryx is more robust than Quetzalcoatlus, say, or that Arambourgiania has a longer neck or whatever.

Just to rain on the parade even more, I've recently spent a lot of time with casts of the Hatzegopteryx holotype material: it represents, so far as I can see, an animal identical in size to Q. northropi. I have a template of how large, roughly, the upper arm of a 12 m span pterosaur should be and the Hatzegopteryx arm material _swims_ around it, man: there's no way it sported 6 m wings unless it defied all scaling trends we see in other pterosaurs or had very different proportions to all other azhdarchids. Given that there's no evidence for either, I think we have to accept the lower of the published figures of this animal (10 m). What's more, the skull, championed as being half-a-metre wide (though I suspect it's more in the 40 cm ballpark) may not be much larger than we should expect in a big Quetzalcoatlus. So, all the talk and fantastic images of 12 m span pterosaurs may, for the time being, be the stuff of fancy. Still, as anyone who's ever seen a fully realised model of a 10 m span azhdarchid can confirm, a 10 m is _plenty_ big enough.