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Re: Spinosaur crests & sails



To James:

Check out the skulls of Suchomimus, Baryonyx, and
Irritator to see some of these crests I mention. The
fact that there are plate-like crests on these guys
makes me think spinosaurs used a quick forward snatch,
instead of slowly moving their heads back and forth
until they sense their prey (like some wading birds),
but spinosaurs seem to lack the traditional sigmoidal
shape to the neck which would be needed when preparing
for the strike...However, one synapomorphy of
Baryonychinae is; "blade-shaped depth of ventral keel
on anterior dorsals", which would occupy the same
position as hypapophyses and may have had a similar
function? It's curious that they don't migrate up to
the cervicals, though. So, if it can't strike very
well, and doesn't employ a sweeping mode of hunting,
then it probably just swam (or waded) right up and
nailed the critter it was after. Personally, I don't
think many theropods had trouble swimming. If I
remember correctly, Spinosaur tails have transition
points further back in the caudal series than most
tetanurans...this might be a secondary loss of
intervertebral articulation in response to the need
for more efficient swimming. Perhaps the reason these
particular species grew so large was due to their
semiaquatic lifestyle. It makes me wonder if the
massive arms and claws could have been used to help
lift their huge bodies when getting out of the water
or steadying themselves on boulders or logs in a fast
current. You're probably right about the age
difference between Deinosuchus and Suchomimus, but I'm
sure other similarly-sized crocs were present in its
habitat. Must go TTYL

-Waylon    
   
--- JAMES ARONIS <Apollo@MLink.net> wrote:
> Very interesting theory, although I wasn't aware of
> any cranial crests
> among the Spinosaurs. In addition, I believe that
> Spinosaurus predated
> Deinosuchus by several million years, IIRC.
> Moreover, it is not known if
> Spinosaurus or its relatives were as aquatic as the
> crocodilians.


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