Re: Belly Ribs and Breathing

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

> David Marjanovic wrote:
> > Uncinate processes are much more widespread (Willo
> > the *Thescelosaurus* has
> > huge uncinate plates).
>
> Are you suggesting that ucinate processes are present
> if not in an ossified form, then in a cartilaginous
> form in all Dinosauria? Or is this simply a case of
> convergent acquisition?

No idea, obviously, because cartilage always leaves only negative
evidence...

> If the latter is true, it has
> no bearing, as there is usually only 1 or a few best
> ways to solve an evolutionary problem.
>     As for the role of gastralia in breathing....
> I don't believe they were muscle powered

They are exactly in the position where you'd expect the abdominal muscles.
Look at your own ones -- don't they look segmented somehow? :-)

> (since some dinosaurs fused them together)

Not all gastralia at once, just e. g. the medial parts of the same pair or
so...

> I wish I knew the
> details of the contact between sets of gastralia; it
> could be illuminating in this discussion.

All I know is that the few people who have taken close looks at theropod
gastralia say they interlock in very complex ways... plesiomorphically (e.
g. in pterosaurs) they aren't connected but are just U-shaped elements lying
in the belly wall.

> TTYL

What do this and AWOL mean?