RE: T. rex forelimbs (was Carnotaurus)

["R. Irmis" <rbi@dana.ucc.nau.edu>]

<<Being somewhat familiar with the tyrannosaur literature (;-), I can say
that
NO ONE has yet published a study plotting relative robusticity of tyrant
dino arms with increasing size.  As such, it has yet to be demonstrated that
_Tyrannosaurus rex_ has considerably more powerfully built arms than a
_Gorgosaurus_ or _Albertosaurus_ scaled up to that size.  (_Tarbosaurus
bataar_, though, does seem to have greater reduction of the forelimb than
_T. rex_).>>

Thanks for jumping in.  Some of my comments are based on conversations with
a large theropod specialist.  I hesitate to mention his name for fear of
putting words in his mouth, etc.  I find it intriguing that *T. rex* limbs
could have actually been functional.  Thought I'd throw it out on the list
to get a response, and indeed I did!

<<However, comparing equivalent sized humeri of _Tyrannosaurus rex_ and
_Acrocanthosaurus_ (a similar sized taxon), we see that they are of
comparable length, but the latter has MUCH larger muscle attachments.
Tyrannosaurid limbs, in general, were lightly muscled compared to   the arms
of at least that big carnosaur.>>

Isn't this a bit like comparing oranges and grapefruit(I know, its an odd
analogy!).  Yes, they are both large theropods, but from completely
different linneages as your own studies show.  I was just comparing *T. rex*
to the rest of the Tyrannosauridae.  BTW, I am going to try and make it to
the Watson Armour Symposium on Large Theropods at the Field Museum if at all
humanly possible!

Regards,
Randall Irmis