Bird hands (was Re: Metriacanthosaurus)

["Thomas R. Holtz, Jr." <th81@umail.umd.edu>]

At 02:49 AM 3/2/98 -0000, John Jackson wrote:

>By the way - where do we stand on the I II III/II III IV digits business?  I
>believe Archy and all modern birds and "protobirds" have II III IV; any I II
>III theropods will just have to have sprung separately from 4 or 5 fingered
>forms in the T (maybe even something like Protoavis).

Compare the manus of Deinonychus, Velociraptor, Sinornithoides, Oviraptor,
and Archaeopteryx.  Based on the evidence you see there, what would you use
to suggest that the former three had a different set of digits than all
modern birds and "protobirds"?

Compare the manus of Allosaurus and the above forms.  Based on the evidence
you see there, what would you use to suggest that Allosaurus had a different
set than the forms above?

Compare the manus of Coelophysis, Dilophosaurus, or Ceratosaurus with all
the above forms.  Same question.

Compare the manus of Herrerasaurus, prosauropods (Plateosaurus, for
example), and Heterodontosaurus, and all the above forms.  Same question.

Compare the manus of a pseudosuchian, a lepidosaur, and all the above forms.
Same question.

That should help answer the question from a comparative anatomy point of view.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661