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Re: DinoMorph Strikes Back!... or does it?



This may all be part of the "Dinomorph Project", but let's not confuse this with computer reconstructions done using the Dinomorph software. This is Photoshop manipulation of illustrations; frankly, it's no less "artistic" than the other reconstructions that are lamented on the same page.

Photoshop composites depend strongly on the accuracy of the illustration (sort of hard to quantify off hand...), and any errors by the original artists will be faithfully passed on in the Photoshop composites. Another, more intractable problem is that the search for "wedge shaped" centra in procoelous vertebrae cannot be done simply by looking at lateral views of the centra. Mechanically speaking, the "wedge" or "keystone" shape that causes an upward (or downward) arch arises from the articulation of the centra. Since sauropod cervical articulations are convex/concave, this cannot be ascertained simply by looking at the posterior rim of the centra.

The Dinomorph Camarasaurus page credits the Wyoming Dinosaur Center as having mounted a Camarasaurus with a neck in the horizontal posture "very much in agreement with the osteological evidence", the skeleton was in fact mounted that way because of the media exposure the Dinomorph project had received. To do so resulted in a gap between the zygopopheses of the anterior dorsals that you could shove a man's thigh through, see here:
http://skeletaldrawing.com/sauropods/disarticulated.jpg


In light of the unacceptability of this, we recently remounted it in a closer approximation of articulation. This resulted in an upright neck, albeit not one as upright as Greg Paul used to restore. A photomanipulation of the actual bones that was used to figure out how we had to changes the armature can bee seen here:

http://skeletaldrawing.com/sauropods/articulated.jpg

Unfortunately we were constrained to modifying the existing armature, so the bones are perfectly articulated. That said, it is much closer now than it was in the neck-straight-out position. We are in the process of scanning all the bones into 3D computer space, but manipulation of the bones in a sand box confirmed that there was no way to keep the anterior dorsals in articulation and have the neck coming straight out at the shoulders.

Kent is doing some exciting work, but manipulating drawings in Photoshop has its own share of error sources. It's worth pointing out that it isn't simply "artists" who have argued for an upright neck posture in some sauropods. Per Christiansen, among others, has published biomechanics arguments that support this interpretation. Don't get me wrong, the jury is still out on how many (if any) sauropods held their necks upright, and if so, how high. But Photoshop manipulation of drawings is no stronger a form of evidence than the skeletal reconstructions that proceeded the technique. What we really need are good 3D data sets from well preserved and complete specimens.

Hold the phone on that request...

Scott Hartman
Science Director
Wyoming Dinosaur Center
110 Carter Ranch Rd.
Thermopolis, WY 82443
(408) 483-9284

www.skeletaldrawing.com