RE: T-rex Finger Count?

[Ken.Carpenter@dmns.org]

First, not an inane question.
Be careful, however, in assuming that tyrannosaurids were IN THE PROCESS
of losing metacarpal III. There is no reason to assume that is true just
because it no longer has functioning phalanges. In fact, relative to the
rest of the (functioning) metacarpals, metacarpal III is not
proportionally smaller than what is seen in Gorgosaurus. Metacarpal III
still has an important function: providing the insertion points for the
flexor carpi and extensor carpi in order to flex or extend the hand. In
the Peck's rex specimen, the insertion points for these two important
muscles are partially ossified (entheses) leaving shallow insertion
"pockets".

Kenneth Carpenter, Ph.D. 
Curator of Lower Vertebrate Paleontology 
and Chief Preparator 
Department of Earth Sciences 
Denver Museum of Nature & Science 
2001 Colorado Blvd. 
Denver, CO 80205 USA

Ken.Carpenter@DMNS.org
ph: 303-370-6392/ or 6403 
fx: 303-331-6492 

for PDFs of my reprints, info about the Cedar Mtn. Project, etc. see:
https://scientists.dmns.org/sites/kencarpenter/default.aspx
for fun, see also:
http://dino.lm.com/artists/display.php?name=Kcarpenter



 

> -----Original Message-----
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu] 
> On Behalf Of Jordan Mallon
> Sent: Monday, June 06, 2005 3:50 PM
> To: dinosaur@usc.edu
> Subject: Re: T-rex Finger Count?
> 
> On 6/6/05, Ken.Carpenter@dmns.org <Ken.Carpenter@dmns.org> wrote:
> > Smith and  I assumed it was there because it is there in 
> Gorgosaurus.
> 
> I figured as much.  I guess my question is more along the 
> lines of 'considering that tyrannosaurids were in the process 
> of losing digit 3, is the argument that T. rex retained mc 
> III any stronger than the argument that it lost it'?  It's a 
> bit of an inane question, admittedly, but I thought I'd ask.
> 
> --
> Jordan Mallon
> 
> B.Sc. (Honours), Carleton University
> Vertebrate Palaeontology & Palaeoecology
> 
> Paleoart website: http://www.geocities.com/paleoportfolio/
> http://dino.lm.com/artists/display.php?name=Mallon
> MSN Messenger: j_mallon@hotmail.com
>