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RE: Samson the T. Rex



 
Have a look at some alligator/crocodile skulls.  At some point in their
growth, they stop getting a whole lot longer and they just get more and more
robust.  They get downright gnarled and ugly as a matter of fact.  I think
that it is no coincidence that "Sue" is the oldest and most robust of the
lot (save for MOR 008- big and ugly).

Darryl Jones  <dinoguy@sympatico.ca>

For information on tyrannosaurids and
cool activities and information for kids,
visit my web page at:

http://www3.sympatico.ca/dinoguy/   
-----Original Message-----
From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of
Michelle Pinsdorf
Sent: October-02-09 7:33 PM
To: dinoboygraphics@aol.com; dinosaur@usc.edu
Subject: Re: Samson the T. Rex

Agreed, just because one 'large' T. rex has proven to have medullary bone,
it doesn't mean that ALL 'large' T. rex specimens are therefore female.
There has to be a lot more sampling before such a supposition can be made,
and just like line of arrested growth age analyses, this type of sampling is
hampered by the fact that there aren't a ton of nice, undistorted,
taxonomically sound T. rex long bones out there.

The concept of a 'robust' and 'gracile' morph of T. rex existing A) ignores
the fact that juvenile members of the species are much more gracile than the
adults and B) most of the characteristics that distinguish these morphs are
cranial ones. It's been shown that tyrannosaurids have a significant degree
of individual variation in their crania, much like we do, especially given
the effects of aging. Many T. rex crania have the added bonus of pathologic
injuries, distorting the characteristics used to determine the morphs. 

In the end, like Scott says, the sample size is too small (for now anyway!)
to make any conclusions about sexual dimorphism in T. rex specifically,
especially when those conclusions include subjective characters.

Michelle Pinsdorf
South Dakota School of Mines and Technology