Arms for a Carnotaurus

[Adam Yates <zooamy@zoo.latrobe.edu.au>]

On Fri, 3 May 1996, th81 wrote:

> Short, but MASSIVE.  Huge muscle attachments.  Powerful claws.  Not at all
> like the (grotesquely) shortened arms of _Carnotaurus_ (which, incidentally,
> has a very well developed scapulocoracoid: for what,I have no clue).

Speaking of Carnotaurus arms, I've only just got hold of a copy of the 
description of this beast published by the LACM. In it the authors state 
that the humerus had lost the torsion between the proximal and distal 
ends, and that the radius and ulna did not cross as they do in other 
theropods. This straightening out of the arm was supposed to have rotated 
the orientation of the hand so that the palmar surface faced anteriorly! 
(at least that was my understanding of their writing)This seems totally 
bizare and I have great trouble imaging how it could work. In Stephen 
Czerkas's model it appears that the palms face medially like other 
theropods. Has anyone actually seen the fossil or good casts? Which way 
is the hand oriented? One other point is that the drawing of metacarpal 
IV looks like a large Iguanodontid thumb-spike, yet it is not discussed 
in the text. Could Carnotaurus have used its arms for offensive weapons? 
(this might explain the increased range of movement at the shoulder joint)

"Smoke me a kipper, I'll be back for breakfast"

Adam Yates