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Re: Daspletosaurus?



At 09:25 AM 2/2/98 -0700, you wrote:
>
>> is it possible that Trannosaurus itself became larger because of the
>> seeming shift in the duckbill/ceratopsian ratio, and the resultant need
>> to go after more dangerous prey?
>
>     I've wondered about this trend for a while, as to if it really
>exists, not just among dinosaurs but reptiles in general.  Tyrannosaurus,
>Triceratops, Anatotitan and Edmontosaurus are certainly large compared to
>Judithian North America dinosaurs, but what about other dinosaurs, and
>other reptile groups?  _Mosasaurus_ has been touted as the largest
>mosasaur, although I've learned that _Tylosaurus_ got as large.  An then
>there is _Queztocoatlus_. How to the giant crocodilians of the Late
>Maastrichtian compare with, say, big Judithian crocodilians?  IS there a
>general trend among late Maastrictian reptiles to get especially huge
>compared to related late Campanian forms?    
>
>LN Jeff
>O-
>
>
        Back in my salad days, Dewey McLean published a paper in
_Science_Vol.201, 4 August 1978, titled _A Terminal Mesoic "Greenhouse":
Lessons from the Past_. McLean suggested that cooling into the middle
Maestrichtian resulted in larger dinosaurs which were then wiped out by a
sudden rise in global temperature. This, of course, was pre-Alvarez, but I
thought it a very compelling paper with references to the Colbert, Cowles,
Bogert alligator observations. You might want to check it out.
        Dan Varner