Re: Ornithodira, breathing with long necks

["T. Mike Keesey" <tmk@dinosauricon.com>]

On Thu, 12 Apr 2001, Rob Gay wrote:

> It doesn't need to be. But, it is more likely, I think. Where is the
> evidence for the avian lungs and 4 chambered heart, though?

The living outgroup to _Dinosauromorpha_ (_Crocodylia_) have
four-chambered hearts, as do extant _Dinosauromorpha_ (_Neornithes_), so
four chambers should be the default assumption.

As for avian-style (technically, neornithean-style) lungs, might
pneumaticity in the skeleton be some indication for this? (air sacs)

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