Re: An Odd Question on Tyrannosaurs.....

[MKIRKALDY@aol.com]

Posted for Chris Brochu:
_________

Nick Longrich said:

>Brochu showed at the mexico SVP meeting that Lambe's Gorgosaurus 
>"sternum" is actually two fused pairs of gastralia,

A note of caution - I showed that the Albertosaurus "sternum" *might* 
be the anteriormost fused gastralia.  Since I didn't see the 
"sternum" during my last visit to Ottawa, this needs to be 
cross-checked.  My conclusion was based on the fact that a big 
triangular mass of bone is present between the anteriormost gastralia 
in Tyrannosaurus (at least 2 specimens) and Tarbosaurus (at least one 
figured by Maleev), and the bone figured by Lambe *looks* like it 
could be this.  Moreover, other very complete tyrannosaurid skeletons 
lack an unambiguous bony sternum.  But, no firm conclusions have been 
drawn yet.

Clark et al's 1999 description of the nesting oviraptorid has the 
most complete discussion to date of the distribution of sternal and 
gastralial characters among theropods, though they accepted Lambe's 
identification of the odd bone in Albertosaurus as a sternum.

chris

-- 
------------------------
Christopher A. Brochu
Assistant Professor
Department of Geoscience
University of Iowa
Iowa City, IA 52242

christopher-brochu@uiowa.edu
319-353-1808 phone
319-335-1821 fax

www.geology.uiowa.edu/faculty/brochu