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Re: What did Spinosaurus eat? New species of Lepidotes found
On 3/3/2011 3:56 PM, David Marjanovic wrote:
-Regarding [...] Bailey's hump hypothesis...
No. Just... no. :-)
No, really, there's no evidence for a hump. There just happen not to be
any mammals with a sail, and Bailey doesn't seem to have looked at
squamates like *Hydrosaurus* very much.
Physical law indicates that all other factors being equal, large objects
have more trouble dumping heat than smaller ones, due to the familiar
It follows logically that within a bio-design in which sails are
advantageous as 'heat dissipators', sail areas would optimize to
increase in proportion to body mass, rather than surface area, assuming
environment is constant.
A large animal w/ terrestrial locomotion that spends a lot of time in
full sun and warm shallow water might need a heat radiator, and be a
prime candidate to evolve a sail.
Some calculate a sail would absorb more heat than it radiates, but
orientation of the sail relative to the sun's rays would be entirely
volitional in the spinosaurid case -- this obviously could minimize the
energy absorbed by the sail.
Is the record complete enough to state w/ any confidence that sails are
proportionally larger in large spinosaurid species as opposed to smaller
species, thereby fulfilling the prediction that follows from a
speculated heat radiator function for a sail?