Re: sauropods: homotherm,heterotherm or gigantotherm?

[David Marjanovic <david.marjanovic@gmx.at>]

> What about large ornithopods or therizinosaurs?
> Couldn't they have munched on conifers too?

Sure, but only on the lowest branches, while most sauropods would have 
reached higher even if they held their necks horizontally.

> Abstract: "[...] crocodilians retain a four-chambered heart.  However, 
> crocodilians have a neurally controlled, pulmonary bypass shunt that is 
> functional in diving.  Shunting occurs outside of the heart and involves 
> the left aortic arch that originates from the right ventricle, the foramen 
> of Panizza between the left and right aortic arches, and the cog-tooth 
> valve at the base of the pulmonary artery.  Developmental studies show 
> that all of these uniquely crocodilian features are secondarily derived, 
> indicating a shift from the complete separation of blood flow of 
> endotherms to the controlled shunting of ectotherms.  We present other 
> evidence for endothermy in stem archosaurs and suggest that some dinosaurs 
> may have inherited the trait."

I still haven't read that (because I haven't stumbled across the journal --  
the library here should have it, however), but... that developmentary 
evidence must be interesting. We have a foramen of Panizza before it closes 
at birth (allegedly due to the sudden pressure of the first cry).

> > There is one known living gigantotherm: the leatherback turtle 
> > (*Dermochelys coriacea*).
>
> Tuna and some sharks (e.g., great white shark, makos) also have
> some kind of endothermy ("regional endothermy"),

Yes, but that's not gigantothermy. Those tunas (not all) and sharks do have 
increased metabolic rates.