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Re: Tarbosaurus



-----Original Message-----
From: Jeffrey Martz <jeffmartz@earthlink.net>
To: Dinogeorge@aol.com <Dinogeorge@aol.com>
Date: Saturday, July 22, 2000 4:20 PM
Subject: Re: Tarbosaurus


>
>Dinogeorge wrote...
>>Again, we all know about these, but how could you tell which, if any, were
>>operating at any particular place and time to cause the observed
>>>differences< between the collection differences between Mongolian and
>North
>>American tyrannosaurid specimens? Sure, you can imagine a gazillion
factors
>>that might cause preservational biases, but if you can't constrain them,
>>they're pretty much useless.
>
>
>    Bringing back up a point that you've been dodging through this entire
>discussion, lets forget about juvenile specimens for a minute and just look
>at absolute numbers of tyrannosaurs in Hell Creek and Nemegt.  In Hell
>Creek, tyrannosaurs represent a relatively small percentage of dinosaurs,
>but in Nemegt they are much much much more common.  You've been presenting
>your "null hypothesis" that 1) fluvial preservation in the Negmegt and Hell
>Creek Formations is identical, and that 2) tyrannosaur behavior in the Hell
>Creek and Nemegt Formations are identical.   There is DIRECT evidence that
>at least one of these assumptions is wrong, because if they were both
>correct, the percentages of tyrannosaurs preserved in the Hell Creek and
>Nemegt Formations would be identical...but they aren't.  Something IS
>different George, whether or not we can identify the particular cause!
>    So now we have evidence in the form of the studies of Rozhdestvensky
>(1965), Carpenter (1992) and Carr (1999) which present morphological
>evidence that in addition to tyrannosaurs being overrepresented in general,
>juveniles are particularly overrepresented.  What is your only evidence
>against this claim?  That tyrannosaur preservation in the Hell Creek and
>Nemegt formations should be identical!  The fact that we can't identify the
>particular causes why there are preservational differences between
juveniles
>and adults doesn't mean the evidence for them doesn't exist!
>     Your entire response to my mentioning Rozhdestevensky and Carpenter
>before was just to point out that Carpenter took out Maleevosaurus.  Fine
>George, Ken took out Maleevosaurus!  How about the growth series he set up
>using the other specimens he assigned to juveniles of Tarbosaurus bataar?
>Why don't you answer the WHOLE argument rather then just the parts that
>don't contradict your ideas, George?
>
>LN Jeff
>
>Fear not those who argue but those who dodge.
>-Marie von Ebner Eschenbach
>
>Jeffrey W. Martz
>3002 4th St. # C26
>Lubbock, TX
>79415
>http://illustrations.homestead.com/Illustration.html
>(806) 747-7910
>
>
>