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Re: [Re: _Scipionyx_ and diaphragms again]



"David Marjanovic" <david.marjanovic@gmx.at> wrote:


> The pleurocoels (and analogous pneumatic holes in the pubis of
> *Archaeopteryx*, the ilium and furcula of the new carcharodontosaurid, and
nearly all bones of recent birds) are weight reducers because they are
> filled with air. I've heard that an eagle's feathers weigh OVER TWICE AS
> MUCH as its skeleton. Now how can air get there if those holes and
> depressions aren't connected to the respiratory system?

++++++++++++++++++++++++++++++++++++++++++++++++++

Perhaps I should have rephrased that a bit. I obviously know that there would
have to be some minor connection to the respiratory system for air to get in,
I just meant if it played a large role in breathing.

A reason for bringing this up is because we have a multitude of snake species
with an air sac system that is part of the pulmonary system, but does not,
apparently, play a role in respiration (or at least not in normal respiration,
it might come into play with extensive breathing).

To put it another way, do we know if the air sacs in dinosaurs were part of a
one way breathing system as in birds, or if there was the typical dead end
system seen in other tetrapods?

The papers (abstracts) on sauropod breathing sound interesting. Do you happen
to have the refs handy?

Jura

Jurassosaurus's Reptipage: A page devoted to the study of and education on,
the reptilia:

http://reptilis.net

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