Purgatorius

[Phil Bigelow <bigelowp@juno.com>]

"David Marjanovic" <david.marjanovic@gmx.at> writes:

> > >> Primates cca 75 Ma ago
> > >
> > >No, fewer than 65.
> >
> > Isn't there something called Purgatorius that's supposed to be 
> about 75Ma?

> This is one single tooth that was found in a sieve which had 
> previously been
> used to screenwash Paleocene sediments, in which *Purgatorius* is 
> quite
> common. In other words: I don't believe it.
> http://www.dinosauria.com/jdp/misc/hellcreek.html#mammals (Even 
> though
> plesiadapiforms like *P.* do seem to be primates now.)
> 
> 


I was afraid this subject would come up.  I fear I may be involved in
having spread an urban myth about sieving contaminiation in the Van Valen
and Sloan study.  Coincidentally, I just got an e-mail the other day from
Don Wolberg, asking me where I got that information.  Frankly, I can't
remember.  I *used* to believe that I read it in a paper somewhere, but
so far I can't find such a published claim/accusation.

Back in 1995, we had a discussion here on "Purgie", so, at wit's end, I
searched the DML archives and dug up the following archaic thread.  This
may be my only "source" for the claim:

http://www.cmnh.org/dinoarch/1995may/msg00274.html

I have a request:  If anyone knows of a publication that suggests that
_P. ceratops_ may actually be Paleocene because of "screening
contamination", please let me know.  If I don't find a published source,
I'll yank that paragraph from the Hell Creek Faunal List.


<pb>
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