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Re: Tarbosaurus?



Dinogeorge wrote...

>Well, as soon as you can describe what these differences in preservational
>biases between Mongolia and North America might be, and how they would
affect
>a population of tyrannosaurids so as to increase the number of preserved
>juveniles and subadults relative to the number of adults, we can talk some
>more.


    Sure, just as soon as YOU provide evidence that the preservational
biases againt juvenile tyrannosaurs were precisely identical in two
different depositional environments on two different continents which
already show evidence of other differences in preservation involving
tyrannosaurs.  Can you, George?  I can't explain how you get such unusually
high preservation of tyrannosaurs in general in the Nemegt Formation
compared to Hell Creek, but it seems to have happened regardless.  We're
both just hypothesizing here, but your assumption that the preservation
ratio of juvenile and adults should be identical in the Nemegt and Hell
Creek Formations is unfounded.
    The only real evidence we have whether or not the big and little
Tarbosaurus specimens belong the same species or not is morphological, and
morphological studies suggest there is a gradation in size and morphological
change between the little and big tyrannosaur specimens consistant with
ontogenetic change.

LN Jeff

He who stops at being better stops being good.
-Oliver Cromwell

Fear not those who argue but those who dodge.
-Marie von Ebner Eschenbach

Jeffrey W. Martz
3002 4th St. # C26
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