RE: Two tyrannosaur questions

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

David Marjanovic wrote:

> If a T. rex were
> standing still and holding its arms in a "relaxed" position, would its
>palms more likely be facing the ground or facing inwards towards its
>midline?

>Facing inwards towards each other, and it was unable to change that. 

I wonder if this might have been the case for most maniraptorans as well,
especially that subset of maniraptorans (eumaniraptorans and oviraptorosaurs
included) that show an enlarged semilunate carpal block.  In these forms, if
the forelimbs were extended forward from the body, with palms facing inward
(such as if the theropod was saying "I caught a fish - THIS BIG!"), the
hands could only flex in the 'lateral' (radio-ulnar) plane.  Hence, the
palms would continue to face one another.

Of course, as David said, dromaeosaurid forelimbs were a lot more useful
than tyrannosaurid forelimbs.  But in both groups, the pectoral skeleton was
perhaps only really effective when both forelimbs were used in tandem, with
the two hands acting in opposition. 



Tim