Henri,
To the best of my
knowledge, pneumatic foramina have not yet been identified in the limbs of any
theropod. In birds, the cervical airsac aerates the cervical + thoracic
vertebrae, the clavicular airsac aerates the pectoral skeleton, and the
abdominal airsac aerates the hind limbs, pelvis, sacrum and caudals. The
anterior and posterior thoracic airsacs do not invade any bones.
The relationship between
various airsacs and those bones the airsacs invade is very consistent,
regardless of which bird is being discussed.
Some theropods (oviraptorosaurs, _Acrocanthosaurus_, perhaps
others;
I'm in the process of moving and all of my refs are boxed)
exhibit pneumatic foramina in the sacrum, pelvis and/or caudals. Assuming
the relationship between theropod airsacs and the bones they aerate was the same
as it is in birds, this suggests some theropods possessed abdominal
airsacs.
Guy Leahy
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