RE: Palms in

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

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Scott Hartman
>
>     Dan Chure certainly appears to be right.  In my paper at the Tate
> Conference I described how the carpal that is homologuous with the
> maniraptoran semilunate allows much the same sort of action,
> although to a
> much smaller degree than in maniraptorans.  Allosaurus can also
> bend  digits
> 2 and 3 slightly backward (as much or more than it appears
> Denonychus could)
> so this may not be as weird as you think.  I'm not sure that any
> of this is
> indicative of a phylogenetic relationship closer than what has been
> hypothesized by Holtz, Padian, or others, but rather they were probably
> common adaptations plesiomorphic to the group that gave rise to
> maniratorans.

Quite so.  Most recent phylogenetic analyses (my own, Sereno's, etc.) still
find _Allosaurus_ as more distantly related to birds and dromaeosaaurids
than are (say) ornithomimids or tyrannosaurids, but also find that the
semilunate carpal block is more broadly distributed than previously
envisioned.  It seems to be (minimally) an avetheropod character.

                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): 301-314-7843