Re: no feathers on Pelicanimimus

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

At 02:01 PM 6/12/97 -0400, Nick Longrich wrote:
>Norell puts Troodon in the Maniraptora. The AMNH crowd hasn't published
>anything on this yet but he says as much in the _Audubon_ issue with
>Sinosauropteryx, at least I think that's where I read it. Tyrannosaurs and
>Ornithomimids lack some birdlike specializations to arms, legs and tail
>that are shared by the troodontidae with dromaeosaurs, oviraptoridae,
>and alvarezsaurs and so these two would have to have a lot of reversals.

Although I agree that tyrannosaurid and ornithomimid arms do not show the
same suite of characters as found in "classic Maniraptora" (i.e., those
recognized as maniraptorans in Gauthier 1986), they are NOT reversals, as
they do not return to a more primitive tetanurine state.  Bolth clades are
characterized by unique suites of forelimb features, which might have
evolved from either an allosaur-like or dromaeosaurid-like forelimb.

I am curious as to what leg or tail features you suggest are shared by
troodontids and dromaeosaurids that are not also found in ornithomimids (for
example).

>As I understand things,
>the only two taxa that are guaranteed to be in Maniraptoriformes 100% are
>the ornithomimids and modern birds.

Indeed.

>Anything else is hypothesis. So
>"common ancestor of troodonts, dromaeosaurs, and oviraptoridae" is just
>that strictly speaking, with a chance of some tyrannosaurs and
>ornithomimids as well. 
>       Didn't Cathy Forster's SVP presentation put troodontidae closer to
>birds than dromaeosaurs? and does anyone know what in the heck is going on
>now with the elmisaurs?

Elmisaurids, aka Caenagnathidae, are pretty securely the sister taxon to
Oviraptoridae (based on a specimen to be described by Hans Sues in a
forthcoming issue of JVP).

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