Did their lung structure restrict dino's abilities?

[Ccookk <Ccookk@aol.com>]

Fellow Paleo's,
        The article in Science 1997;278 (5341):1267, by Rueben JA, Jones TD, 
Geist
NR,
Hillenius WJ., suggests that the unmodified bellowslike septate lung of
theropod dinosaurs restricted the maximum rates of respiratory gas exchange,
and therefore
restricted their overall activity to that consistant with reptiles, rather
than an activity level typical of active endotherms. According to this
article, only taxa possessing the modified avian flow-through septate lung
were capable of the greater oxygen-carbondioxide gas exchange rates of active
endotherms. Evidently, Archaeopteryx and enanthiornithines also possessed the
unmodified septate lungs as well.
        We have heard a lot about how fast some of the theropods may have run, 
and
how that the early birds may have learned to fly, but this information makes
me rethink just how much these creatures would have been capable of with the
limited endurance resulting from less than optimal gas exchange. Anyone have
any comments? 
Carl