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RE: Spinosaur crests & sails




-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
Marco Mendez
Sent: Wednesday, May 30, 2001 7:49 PM
To: dino.hunter@home.com
Cc: dinosaur@usc.edu
Subject: RE: Spinosaur crests & sails

I wrote:
> >>About the crest, the crest is not so big on all spinosaurs, a long,
low crest (or part of it) can be seen in Taquet et Russell (1998) in
their description of _Cristatusaurus lapparenti_, I know this might be
a
 syno0nym to _S. tenerensis_, but that is another argument. Anyway, an
articulated premaxilla and maxilla are referred to _S. maroccanus_,
a possible junior synonym to _Spinosaurus aegyptacus_, but indeed a
spinosaurine.<<

Tracy Ford wrote:
>> I disagree. I've done some research on this and IMHO _S. aegyptacus_
 had a much shorter and taller skull than _S. maroccanus_.<<<

Sereno et al. (1998) suggests that all spinosaur material from North
Africa from albian- Cenomian- age rocks is to be reffered to S. aegytpciaus.
I have seen both the illustrations of the dentary of
_S. aegypticus_ and _S. maroccanus_. S. maroccanus has a long, low narrow
premaxilla + maxilla. S. aegytiacus seems to be long and narrow.
I am not very sure of the sizes of both, I know they're big. It may be
possible they are the same species but both specimens are at different
stages of growth. (I have discussed this before, and my conclusion was:
we'll find out when a rather complete S aegytpcus is found, or a lower
jaw with the upper jaws of S. maroccanus.
Sereno et al. say that the proportions and adddtional material are
questionable.
Thus, they refer to _S. maroccanus_ as a nomen dubium.<<

I still disagree with Sereno et al, (1998). S. maroccanus has a long
premaxilla and maxilla. Both have nearly a level lower edge. There is a
dentary tip at NMC which I photographed and the dorsal edge is also nearly
straight. Both would go well together.

S. aegypticus has a bulge at the distal end of the dentary. The premaxilla
would have followed this bulge downward and look similar to Suchimimus in
that respect. The dentary in S. aegyptics is short and IMHO would have also
have had a shorter skull than S. maroccanus.

There is a new dentary of S. aegypticus (as I posted before) that is nearly
identical to the type. So in Morocco both S. aegypticus and S. maroccanus
lived together. I don't think they are growth stages because both are
basically of the same size.

One day when I get time I'll do a new illustration of both.

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