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Re: Brrr, bone chilling paleopolar summers(Polar dinosaur growth and other new papers)



On Mon, Aug 8th, 2011 at 12:49 PM, Augusto Haro <augustoharo@gmail.com> wrote:

> 2011/8/7 Jaime Headden <qi_leong@hotmail.com>:
> >
> >   Your inference here, then, is that marine reptiles migrated, which would 
> > imply they have a
> similar metabolic constraint and allowance as marine mammals do which also 
> migrate.
> 
> You mean, similar metabolic constraint and allowance in what sense?
> Because Dermochelys is very active, yet have a basal metabolic rate
> well below that of a similarly sized mammal, and it has been described
> as migratory (http://www.seaturtle.org/PDF/James_2005_EcolLett.pdf).

Great White sharks are also considered migratory, crossing from Australia to 
South Africa and 
back again. I can imagine that Mesozoic marine reptiles may have had similar 
adaptations to 
Great Whites or tuna, allowing for functional homeothermy without the need for 
a high metabolism.

http://www.whitesharktrust.org/migration.html


The number of juvenile marine reptile fossils found in South Australia suggests 
that they may 
have used the cold waters of the ancient inland sea as a breeding ground. These 
are the same 
ocean deposits that glacial drop-stones have been identified from.

See:

Kear, B. P., 2006: Marine reptiles from the Lower Cretaceous of South 
Australia: elements of a 
high-latitude cold water assemblage. Palaeontology 49, 837-856.

Kear, B. P., Schroeder, N. I., Vickers-Rich, P. & Rich, T. H., 2006: Early 
Cretaceous high latitude 
marine reptile assemblages from southern Australia. Paludicola 5, 200-205. 

Kear, B. P., 2005: Marine reptiles from the Lower Cretaceous (Aptian) deposits 
of White Cliffs, 
southeastern Australia: implications of a high-latitude cold water assemblage. 
Cretaceous 
Research 26, 769-782.

Also:
http://www.abc.net.au/science/articles/2006/07/27/1698381.htm?site=galileo&topic=latest


-- 
_____________________________________________________________

Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
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