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crocs and paleotemps



> From: pwillis@ozemail.com.au (Paul Willis)
>
>> Whoooo there boy!!!! If you are going to play the
>> endothermy-for-dinosaurs-because-they-are-in-high-latitide-sites-
>> in-Australia routine you should also be aware that crocodiles,
>> turtles and labyrinthodonts have also come out of these sites. This
>> greatly complicates the picture and indicates that there is some
>> problem with the palaeotemp data for the early Cretaceous of
>> southern Victoria. ...
>
>True enough.
>
>However there is also the North American data.  Here dinosaurs extend
>without noticable problem all the way to the North Slope of Alaska,
>yet the largest crocodilian, Phobosuchus, is not known much further
>north than the Canadian border.

Actually, and much more importantly, the North Slope faunas lack the
lizards, champsosaurs, crocodilians, and turtles that are so very common in
Albertan and western U.S. assemblages of the same age.  _Phobo/Deinosuchus_
was/were a/ very rare taxon/a, but these other forms are VERY common in
latitudes more southern than Alaska.

(As you might guess from some of the above modifiers, there are several
questions regarding the number of giant croc taxa in the Late K).

One final note:  the giant caiman _Purrusaurus_ from the Miocene of Brazil
was comparable in size, if not larger than, the Late K North American
crocs.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661