Re: Dinosaur Genera List corrections #98

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

At 02:11 PM 11/4/98 -0000, John Jackson wrote:
>--Original Message-- From: Dinogeorge@aol.com Date: 04 November 1998 01:14
>
>> The paper also finds several spinosaurid characters in the
>ornithomimosaurian
>_Pelecanimimus_ and suggests that ornithomimids and spinosaurids may share a
>fairly close common ancestor. Food for thought
><

Actually, this is not correct.  Taquet and Russell argue that
*_Pelecanimimus_* and spinosaurids are linked, and futher that _Pel._ is
*not* an ornithomimosaur.  Instead, they consider it an
"'ornithomimid-mimic' related to the spinosaurs." (p. 352).

This is at odds with the buttloads of ornithomimosaurian synapomorphies of
_Pelecanimimus_, as well as characters it shares with troodontids and other
coelurosaurs which are lacking in spinosaurids.

Quite frankly, this seems to be the weakest part of the paper.

>> Wouldn't it be interesting if
>_Deinocheirus_, a problematic theropod that some think is closely related to
>ornithomimids, turns out to be a spinosauroid of some kind?
><

Except _Deinocheirus_ possesses ornithomimosaurian characteristics, and
lacks those of spinosaurids.

>So _Deinocheirus_ isn't a segnosaur then?  Since the weekend
>ornithomimosaurs and segnos might well be mutually exclusive again.

_Deinocheirus_ doesn't have segnosaurian features: it is _Therizinosaurus_
that does.

More info on spinosaurs in the not-too-distant future.

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