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Re: Velociraptor footprints

Dinogeorge@aol.com wrote:
> In a message dated 97-08-04 09:49:19 EDT, smithjb@sas.upenn.edu (Joshua
> Smith) writes:
> << In this discussion of thousands of theropod footprints here and there and 
>  everywhere being correlated to this skeleton and such and such taxon here 
>  and there, you are neglecting to account for the fact that there are NO 
> There is Tyrannosauropus (or is it Tyrannosauripus?--my reference is not with
> me in San Diego yet), which is based on a large print that can only be that
> of Tyrannosaurus, the only dinosaur capable of leaving a print of that size
> and shape.
        I think it is _Tyrannosauripus_.  My reference is here somewhere...

        Oh come on, George.  Ten years ago _Tyrannosaurus_ was the 
"largest" theropod, too.  Just because there isn't another  theropod in the 
current fossil record from the New Mexico Maastrichtian that is large 
enough to create _Tyrannosauripus_ does not mean that one didn't exist.  
_Tyrannosaurus_ is the only theropod WE CURRENTLY KNOW OF that is capable 
of making that track. That means nothing.  Don't believe me?   I give you 
the Newark Supergroup "theropod" ichnotaxon _Eubrontes_ Hitchcock, 1845.  
There is no animal from the Newark Supergroup in the collections of any 
institution that could have created that footprint.  However, I have the 
measurements of 247 of those footprints sitting here in my computer.  I 
guess there was probably a _Eubrontes_ sized trackmaker out there 

Perhaps I just beat that point a bit to death, but I just think that 
these inferences drawn on the basis of "negative evidence" are very 
dangerous things to do in paleontology.  I can cite three references 
where colleagues have used this same idea to justify their hypotheses 
that _Eubrontes_ tracks were made by prosauropods: i.e., there are not 
theropods large enough to have made them known in any collections.  
So what?  That DOESN'T mean they did not exist.  Before _Ceratosaurus_ 
was discovered, there were no theropods in any collections with horns on 
their noses...

Josh Smith
Department of Geology
University of Pennsylvania
471 Hayden Hall
240 South 33rd Street
Philadelphia, PA  19104-6316
(215) 898-5630 (Office)
(215) 898-0964 (FAX)