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RE: Brrr, bone chilling paleopolar summers(Polar dinosaur growth and other



As Augusto Haro noted, isotopic evidence has shown that--regardless of
phylogenetic affinity--there is good evidence that plesiosaurs,
ichthyosaurs, and mosasaurs DID have specific metabolic elements to handle
colder water: namely, thermoregulation.

http://www.sciencemag.org/content/328/5984/1379.abstract

Whether they would "winter over" (if that term is even appropriate for
pelagic animals) or migrate is something that is currently untested, so
far as I know.

On Sun, August 7, 2011 8:48 pm, Jaime Headden wrote:
>
>   The presence of marine reptiles is _relevant_ because they are reptiles,
> and as such lacked specific metabolic elements to handle harsher polar
> winters. 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. At that point, you need to back
> this statement up with evidence, else is remain rhetoric.
>
> ----------------------------------------
>> Date: Sun, 7 Aug 2011 20:40:54 -0400
>> From: GSP1954@aol.com
>>
>> The presence of marine reptiles in polar waters is not relevant because
>> they could easily move in and out according to the seasons the cost of
>> swimming
>> a given distance in streamlined swimmers being so low.
>>
>> GSPaul
>>
>>
>> In a message dated 8/7/11 5:35:28 PM, augustoharo@gmail.com writes:
>>
>> << Bakker wrote mosasaurs were also present at high latitudes,
>> but given that isotopes show they had a high body temperature, their
>> metabolic or activity regime would have much differed from that of
>> Recent squamates, turtles and crocodiles. >>
>>
>> </HTML>
>
>


Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA