RE: Swiming spinosaurus

["Jaime A. Headden" <qilongia@yahoo.com>]

Gunter Van Acker (gunter.vanacker@electrabel.com) wrote:

<<2. Since the unrelated Spinosaurus, Rebbachisaurus and
Ouranosaurus all seem to have had a dorsal sail, and they all
had different behaviour (a carnivore and 2 herbivores with
different feeding strategies), it's possible that the evolution
of a sail-like structure was triggered as an adaptation to an
unusual environment. The mid-Cretaceous North Africa may have
known long seasons when food was scarce (e.g. few plants because
of drought, which forced herbivores to migrate), and the "sail"
was actually more a sort of "hump" where fat was stored when
food was abundant. This theory has been forwarded before.>>

BJ Strata (bjstrata@hotmail.com) [must we use nicks and not real
names here? :)] wrote:

<While I had previously considered heat-regulation as the reason
for convergent sails in these three VERY distantly related
dinosaurs, this second theory is quite appealing. I would
dismiss the first theory, as it seems highly improbable that
such distantly related animals would evolve such similar sexual
"lures." However, the second theory "just feels right," as one
of the list members so eloquently put it (I apologize that I
forget whom waxed eloquent :-). How do the neural spines in
these dinosaurs compare with extant mammls with such "neural fat
stores," such as camels, bison, and ... I can't think of any
others (I know horses have tall "withers," but I don't know of
fat stores).>

  I suggest people check the archives, as this thread has been
thouroughly discussed, and the above concept has some detractors
to it that have been raised in the past. Search terms "hump" and
"sail" may elucidate this; I bring attention to Steve Brusatte's
discussion, and at that time on the list (in the archives, by
date) this was extensively described.

http://www.cmnh.org/fun/dinosaur-archive/2001Jan/msg00477.html

=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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