re: Sauropods and lung development

[Scott A Hartman <ottscay@uwyo.edu>]

>>>>(air sacs) been secondarily modified for weight reduction in sauropods
and
increased gas exchange efficiency in theropods and birds.  The
predatory advantage in having the head at the end of a long and flexible
neck is as yet unproven, but could only have been an advantage if the
respiratory system supported it.  <<<<<

Actually, while the weight reduction advantage of pleuoceols has been
advanced by authorities ranging from _When Dinosaurs Rule the Earth_ to
Jack Macintosh, I doubt that this was their main function.  Both
Indricotherium and Mammuthus grow to average sauropod sizes, and neither
shows any tendancy toward the enginnering marvels that sauropod vertebrae
became (has anyone besides Greg Paul taken the time to compare the dorsal
vertebrae of sauropods and mammals of equal mass?  The sauropod verts are
faaarrrrrr more robust.  An interesting trait in critters with a
supposedly less active lifestyle).  Anyway, I suspect that the pleurocoels
primary function was the same as it was in their ancestors; respiration.
The fact that sauropods elaborate the system to a greater extent then many
theropods and birds is probably a reflection of the rigourous aerobic
demands of combining long necks with gigantism.

Scott Hartman