Theropod respiration questions

[Dino Guy and Computer Gal <gbabcock@best.com>]

In Guy Leahy's article, "Noses, lungs, and guts," from Gregory S. Paul's
_The Scientific America Book of Dinosaurs_, Leahy describes the
osteological characters of non-avian maniraptoran theropod anatomy that
would correlate with an avian respiratory system: double headed ribs,
short anterior trunk ribs, long mid-trunk and lumbar ribs, large
ossified sternal plates (with articulating facets for five sternal ribs
in _Sinornithosaurus_), highly excavated neck and anterior trunk
vertebrae (and pelvis and caudal vertebrae in _Oviraptor_, suggesting
abdominal air sacs).  Tracy Ford's recent article in _Prehistoric Times_
on gastralia puts forward the hypothesis that gastralia featured sliding
linkages which would have enabled theropods to expand and contract the
abdominal space in order to pump air through the respiratory system.

Taken together, these observations (and related functional hypotheses)
offer an x-ray view of the theropod torso as a dynamic cage of intricate
linkages that would provide considerable expansion and contraction,
facilitating highly efficient respiration for these (apparently) very
active animals.

Questions:
What muscles would control these articulations?  Where are these muscles
located?
Would the rib cage contractions synchronize with contractions of the
gastralia, or would the ribs contract the pectoral portion of the torso
while the gastralia expand the abdomen?  Would it make any difference?
What respiratory function (if any) do uncinate processes serve?

-- Ralph W. Miller III   ralph.miller@alumni.usc.edu

(ignoring for the purpose of this discussion the hypothesis that
_Sinosauropteryx_ utilized preparator's glue to facilitate lung
ventilation)...