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Re: _Discover_ article



Dave wrote:

> Has anyone seen the article in the December _Discover_ magazine
> about Tomasz Owerkowicz using nasal cavities as refutation of
> hot-blooded dinos and confimation of the mass homeothermy theory?
> He says that dinosaurs lacked turbinates, special organs in the
> nasal cavity of warm-blooded animals.  He also thinks that the nasal
> cavities themselves were too small to allow dinosaurs to inhale a
> sufficient quantity of oxygen to sustain a warm-blooded animal.
> Anyone care to comment on this thesis?

See "Biological Consequences of Mesozoic Atmospheres: Respiratory Adaptations
and Functional Range of *Apataosaurus*" (Richard A. Hengst et. al., in
CRETACEOUS- TERTIARY MASS EXTINCTIONS (Macleod and Keller, 1996, W.W. Norton
& Co.).

This paper concludes that the respiratory system of apatosaurs  would not
have permitted an active lifesytle in the  *modern* atmosphere, and that
*Apatosaurus* may have had a metabolism intermediate between ectothermy and
endothermy. Their study includes the reconstruction of an apatosaur
respiratory system, in part, from an estimation of nostril diameter.  They
also discuss the possibility of elevated oxygen level during the Mesozoic,
allowing "supercharged" breaths.

Caitlin R. Kiernan