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Re: Nemegtosaurus: brach like skull?



Dinogeorge wrote:

>Another unanswered question concerns the position of the external nares in
>sauropods. I've seen no convincing arguments to explain the shift in the
>location of the nares from near the tip of the snout (primitive for
>dinosaurs, not just sauropods) to the skull roof in between the orbits. This
>is accomplished by a considerable elongation of the premaxillaries at the
>expense of the nasals and frontals. Every known sauropod shows at least some
>displacement of the nares caudally from the primitive position; it's a
>sauropod synapomorphy. Why? What purpose did it serve to get the nares away
>from the tip of the snout? It must have aided breathing. Did it help the
>animal breathe better by eliminating the slight to moderate right-angled bend
>the air would have had to make through the skull after passing up that
>enormous trachea during exhalation? Or did it allow the animal to breathe
>continuously while feeding, something like a secondary palate does? If so,
>does this indicate that sauropods >needed< to breathe continuously because
>they had a rapid metabolism?

I have thought os another possibility; perhaps it was to stop conifer
needles going up their nose. Most conifers (as I am familiar with them)
tend to have radiating clumps of relatively stiff, needle-like leaves.
Surely,attacking such a clump for a mouth full of food could result in
having an uncomfortable amount of fodder stuffed up the schnozz. Perhaps it
is better to move the nostrils out of the line of attack. At worst, it
creates a wonderful cartoon image.

Cheers, Paul

pwillis@ozemail.com.au