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Re: ARCHAEORNITHOMIMUS



At 04:51 PM 10/18/98 -0700, Jaime wrote:

>  First, Ornithomimosauria is *Pelecanimumus* (Perez-Moreno et al.
>1994) and Ornithomimoidea; Ornithomimoidea is *Garudamimus* (Barsbold,
>1981) and Ornithomimidae; Ornithomimidae has everyone else:
>*Archaeornithomimus*, *Gallimimus*, and the
>*Ornithomimus*--*Struthiomimus*--*Dromeciomimus* group, in
>increasingly advanced steps (regard the three-taxa group above as one
>step: it's hardly a resolved taxonomic tangle, as Greg Paul and others
>have demonstrated). And *Deinocheirus* most probably falls somewhere
>in there.

Now, hold on there.  Ornithomimosauria will, shortly, be formally defined as
_Pel._ plus _Orn._.  Ornithomimoidea has NOT been formally defined in the
literature: it is so far just a suggestion.

In general, to the list: PLEASE do not go around coining new names and
definitions and acting as if they are formal usage terms.  This will lead
(and has led) to confusion that those of us who review papers have to deal
with...

There is a lot of work being done on ornithomimosaur systematics at the
moment: some well known names are headed for the chopping block...

>Dwight Stewart wrote:
>
><Originally, I had read that this Chinese dinosaur may have been the
>oldest ornithomimid or ostrich mimic dinosaur. But recently an
>acquaintance of mine said that the small 4th finger on the manus has
>brought this into question. I believe that the 3rd digit is the
>shorter one (but am not certain). My question is this: if 5 or 4
>digits is generally a more primitive state, why would the presence of
>a shorter (& then, therefore PERHAPS atrophied) digit in an earlier
>Specimen of potential ornithomimid disqualify it from being an an
>ostrich mimic? Am I missing something here or is the specimen too
>incomplete to tell?>

There are no ornithomimosaur hands I've seen with more than three digits.
Perhaps your friend is confused about hand vs. foot (i.e., as in primitive
ornithomimosaurs having four toes, but digit I being (apparently) lost in
advanced ornithomimids).

ALSO, as Currie and others have pointed out, it is not certain how many of
the specimens currently called "_Archaeornithomimus_" are really _Archaeo._,
since _Garudimimus_ is known from the same units.

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