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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 geometric considerations.

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?