[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Coelurus a maniraptoran (for how long?)




Ken Kinman (kinman@hotmail.com) wrote:

<If you are going to code for ornithoid vs. non-ornithoid egg
shells, you will need to code Therizinosaurs (segnosaurs) as
non-ornithoid. And more importantly, ornithoid eggshells have
also been found for Dromaeosauridae (Deinonychus), so this
character would appear at least twice independently in David's
tree (or have numerous reversals).>

  Unless the eggs were sat on by a deinonych, there's no real
way to ascribe eggshell to this taxon. As for therizinosauroids,
there are _two_ candidates, which even Ken Carpenter
acknowledges, that _could_ be therizinosauroid. They could also
be tarbosaur.<<

Well, according to Makovicky and grellet-Tinner, 2000, they have associated
eggshells with Deinonychus.

Makovicky, P. J., andGrellet-Tinner, G., 2000, Association between theropod
eggshell and a specimen of Deinonychus antirrhopus: First International
Symposium on Dinosaur eggs and babies/extended abstracts, 123-128.

Basically they state that the many remains of eggshells found near AMNH 3015
(a partial Deinonychus skeleton) shows that these are eggshells from a
theropod and not an ornithischian.

<On a more humorous note, having Dromaeosauridae, Rahonavis, and
Archaeopteryx, all jumping backwards so many nodes over the
heads of the already dizzy ornithomimids, may drive them totally
nuts or to finally demand that cladists stop using them as
specifiers for such unstable clades.>

  I think we all understand, Ken ... :) Note, however, that even
David cautions that his analysis is not strict, does not involve
a parsimony analysis, nor did it involve in anyway a cladistic
run. Not to devalue his analysis, but until there is a concrete
method for putting so much space between *Archaeopteryx* and
birds, a relationship only last year suggested (the reverse
being demonstrated for about 30 years), such a relationship,
including Sereno's 1998-1999 position and Holtz' 2000-2001
position, needs to be rigorously tested. I wouldn't use
tyrannosaurs as a specifier if my life depended on it. For all
we know, oviraptorids are birds and *Ingenia* is an
ornithomimosaur as suggested by Gauthier.<<

Well, I'm not one for cladistics, to say the least. I know of a few new
specimens of early archosauromorphs that will sorely tax any systematic
system that is used, can't say more at this time. : >



Tracy L. Ford
P. O. Box 1171
Poway Ca  92074