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Sue's head, cartilage, and whatnot...(kinda long)

Just to respond to a few good points brought up:

Jon, aka Trouble Stirrer:  You maybe right about the room for the cartilage 
between the vertebrae:  10% is a value commonly given, but the amount is 
variable.  I got to play witha  cast of "Stan" this summer, and I suspect 
something closer to 5% is accurate, which may be consistent with the stiff-ish 
backs fo coleurosaurs (or at least tyrannosaurs).  As for the limbs, I don't 
believe in the dogmatic "dinosaurs had thick cartilageouness joints" bit.  I 
don't think they would have had substantially thicker joint cartilage than 
mammals (e.g. a thin veneer of hyline cartilage).  On the other hand, if "Sue" 
really is a subadult (what would be up with that?!), then I am wrong and there 
probably should be more limb-joiint cartilage.  Pick your favorite excuse ;)

David brought up the cartilaginous episternum which is drawn but may not have 
been present.  Although I think there are good phylogenetic reasons to infer 
such a structure, you will kindly notice that I did not draw it on the rigerous 
detail of Sue and what is known of "her."  So the viewer is left to decide 
whether to believe me or not in my assumption.

And finally, Mr. Varner (thanks for the frequent art-related notices, by the 
way Dan!) asked about restoring squashed skulls.  Actually, I think he was 
asking Jon, but since I'm the culprite in this case, I thought I'd chime in 
anyhow.  In the case of FMNH PR2081 the situation isn't quite as bad as it 
appears.  The jugal, squamosal, quadratojugal, and postorbital are more 
disarticulated than deformed, so it isn't too difficult.  The nasals are 
squashed all to heck, but the premax isnt, so with a little tlc inr estoring he 
lacrimal (which isn't too squished, anyhow), ant the premax/lacrimal positions 
nicely constrain the nasals and the dosral extent of the maxilla.

I'm not sure that the "differences" warant generic seperation yet, because I'm 
not convinced that the AMNH skull isn't different in large part due to it's own 
distortion.  But then again, maybe there are two species of tyrannosaur running 
around the maastrichtian of N.A.

All the best,


Scott Hartman
Zoology & Physiology
University of Wyoming
Laramie, WY 82070

(307) 742-3799