RE: Rauhut's Thesis (long)

["Tracy L. Ford" <dino.hunter@home.com>]

-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of rbi
Sent: Friday, July 13, 2001 10:15 AM
To: rob_redwing@hotmail.com
Cc: dinosaur@usc.edu
Subject: RE: Rauhut's Thesis (long)

>My point is that _Monolophosaurus_ is _not_ convergent, it's a different
>structure. Tyrannosaurids have display structures formed from the nasal and
>lacrimal, does that mean that they're closely related?

Now Im really confused.  Your saying that Monolophosaurus' crest is a direct
descendent of ceratosaur cranial ornamentation?

To restate
>_Monolophosaurus_ has a singular ridge, which is not at all analogous to
the
>paired nasolacrimal crests seen in these specimens. According to the
article
>mentioned onlist about flamingos, identical structures can be the result of
>convergence based on selective pressures. With the differences in the
crests
>seen in _D. wetherilli_ and "D." _sinensis_, and the potentially tetanuran
>status of "D." _sinensis_, why should one assume that these crests are the
>same structure?

Across a large group of birds, structures such as this and cranial
ornamentation are not useful, but, it is obviously useful to say that webbed
feet is one of the characters of ducks.  Therefore, double nasolacrimal
crests
*might* be a feature of non-neoceratosaurian ceratosaurs (boy, that was a
mouthful!).

How you can confidently draw all those characters from a small illustration
in
the paper on "D." sinensis, I don't know. I'd like to see someone do a
cladistic analysis to see where *sinensis* falls.  I do have a question, the
authors state that "D." sinensis has 5 premax. teeth, are there any theropod
groups that have this as well?<<

It IS being done. Also studied completely by a team of paleontologist. Will
you people just frigen wait!!!!

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