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Re: Velociraptor footprints



In a message dated 97-08-04 15:27:03 EDT, smithjb@sas.upenn.edu (Joshua
Smith) writes:

<< 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... >>

And here I thought you were saying something that wasn't utterly obvious. OF
COURSE we cannot associate any dinosaurs positively, absolutely with any
trackways. There's rather little in this world that we >can< establish
positively, absolutely. And OF COURSE there are many dinosaur prints and
trackways for which no known dinosaur was the trackmaker.

But here is what you said:

<<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 
CONFIRMED THEROPOD FOOTPRINTS ANYWHERE.>>

And I say that if a trackway shows clawed prints and three functional digits,
with a possible impression of a hallux at the inside rear of the print, then
there's a better than 99% chance it belongs to a theropod. What you're
saying, when you assert that there are no confirmed theropod footprints, is
that there must have been two >distinct< and widespread groups of dinosaurs,
namely, theropods and three-toed-trackmakers, of which theropods left >no<
tracks and three-toed-trackmakers left >no< skeletal remains. This is at
least as unlikely as being dealt a royal flush, no cards wild, in draw poker.
How "confirmed" do you have to have it?