RE: semilunate carpal

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: Chris Fisher [mailto:killerraptor20@hotmail.com]
>
> > >
> > > I have a question: why was the semilunate carpal beneficial to
> > > carnivorous
> > > theropods??
> > >
> >
> >One possibility: it allows a big hand to be able to be tucked next to the
> >body while not in use.
>
> Thankyou for the answer Dr Holtz. But what does this have to do with
> predatory beheviour?

Well, one thing to remember is that not everything that is beneficial to a
predator need have to do with predation!

> I had thought that the semilunate carpal may have something to do
> with the
> hand being swung (swivelled) in a "predatory arc". As the arms
> came forward
> and downward (the "predatory stroke" of the forelimb) the wrists snapped
> inward, allowing the hands to grasp the prey.

Oh, yes, of course.  I thought that was a given here.

However, if the hands were permanently pointed outwards there would be no
reason for the predatory arc, because they would be in position already (and
save some time).  However, this would have the drawback of having big
grasping hands permanently sticking out, and possibly getting in the way in
non-predatory situations.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796