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Re: Brrr, bone chilling paleopolar summers(Polar dinosaur growth and other new papers)
On Sat, Aug 6th, 2011 at 11:07 PM, GSP1954@aol.com wrote:
> Conditions in Australia look even worse, with evidence for permafrost (at
> least down south). There were polar sauropods that could not migrate north
> because of the ocean down under.
It should be noted however that sauropod remains have not been found as far
south as Victoria.
Tom Rich once made a prediction that they would never be found there, and so
far he hasn't been
The modern Antarctic circle (below which there is at least one day per year of
24 hours of light or
darkness) is at 66.5 degrees south latitude. According to palaegeographic
Victorian deposits in Australia would have been at around 75 degrees south
latitude in the Early
Cretaceous, which would have been well inside the modern Antarctic circle.
Although I suppose
the degree of tilting of the planet in the EK might have been different, thus
putting the polar
circles (as they are defined now) at different latitudes than the present.
It seems that Australian sauropods might be better described as 'sub-polar'. If
sauropod tracks along the coast of Western Australia are anything to go by,
then sauropods may
well have been the only Australian dinosaurs that did migrate - although not in
and out of 'true'
Given the basic body shape of sauropods (lending them high surface area to
volume ratios for
their mass), it's not surprising that they seem to have avoided extremely cold
may not have been able to eat enough food to offset the loss of body heat from
their necks and
tails. There is, after all, a limit to how much food you can cram through a
mouth in a set period of time, and low vegetation quality during a time of the
year with constant
darkness wouldn't have helped things. Juveniles would have suffered even more
in such frigid
conditions, as their surface area to volume ratios would have been even higher.
Spatial Data Analyst Australian Dinosaurs
Melbourne, Australia http://home.alphalink.com.au/~dannj