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On Fri, 8 Nov 1996, Brian Franczak wrote:

> Nick Longrich wrote:
> > Sauropods do something similar, I think, with their pleurocoelous
> >vertebrae-  > eliminating the material in the middle, where it doesn't do
> >much good.
> and...
> > That's why dinos have heat problems ( at least, in theory)- surface area
> >being  the only way to lose heat, and a 20-ton Apatosaurus not having a
> >lot of it.
> Wouldn't airsacs in these pleurocoelous vertebrae add to the surface area
> and aid in keeping the animal from overheating?

        Bakker has suggested just this. I think there may be debate as to
whether there actually were air-sacs - some pleurocoels may not have
openings through which air passages could have passed. One wonders whether
this could have made a big enough difference to make dinosaurs much more
able to deal with being big than other endotherms ( i.e. mammals).

        On the subject of forward-pointing teeth- I've been doing some
looking at bones, and there are quite a few animals with a litte bit
of forward inclination to the teeth (moles, those noted piscivores ;)
), so I'm not quite so sure that a single pair of forward pointing
teeth on the end of the dentary of Spinosaurus (not Baryonyx, I didn't
mean to give that impression) is that great an indicator, but it is
still a little unusual among the theropods, you must agree. Can anyone
else think of a predatory dinosaur with anterior direction to the