RE: Evolution of tyrannosauroid bite power

["Thomas R. Holtz, Jr." <tholtz@umd.edu>]

> From: ptnorton [mailto:ptnorton@suscom-maine.net] 
> Sent: Wednesday, December 19, 2007 6:37 PM
> To: tholtz@umd.edu; stearns5@cox.net; dinosaur@usc.edu
> Subject: Re: Evolution of tyrannosauroid bite power
> 
> I'm wondering if the evolutionary increase in the jaw 
> strength of tyrannosaurids is more a function of the adaptive 
> response of the animal as a *system* to its environment, 
> rather than just as some selective pressure acting on the 
> jaws alone.  For example, it seems to me that an adaptive 
> shift in behavior, from snatching and manipulating small prey 
> (as in *Guanlong vucaii*,  in which the hands could do a 
> large part of the work) to using the jaws to dispatch larger 
> prey as quickly as possible (as in *T. 
> rex*) would preferentially select for relatively smaller arms 
> and relatively larger jaws. Animals are complex systems and 
> need to be evaluated as such, more so than as a series of 
> individual elements.
> 
Well, of course, and I think everyone working on this would agree exactly
with that scenario.

But a biomechanical analysis must needs focus on one particular part of the
organism, and later be integrated into other comparable systems.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Earth, Life & Time Program, College Park Scholars
http://www.geol.umd.edu/~jmerck/eltsite/
Fax: 301-405-0796

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA