Re: Fastovsky vs Archibald

[Phil Bigelow <bigelowp@juno.com>]

One point that should be emphasized is that no one (to my knowledge) has
actually conducted a rigorous (e.g., non-anecdotal) sampling/statistical
study of intraformational extinctions within the Hell Creek Formation.

Most of what has been written about certain taxa missing from the upper
part of the formation have been "asides" that were included in papers
describing H.C. taxa in general.  Care should be taken when assigning
weight to such comments.

<pb>
--

On Sat, 18 Jun 2005 03:40:41 -0700 (PDT) Tim Donovan <uwrk2@yahoo.com>
writes:
> 
> 
> --- Phil Bigelow <bigelowp@juno.com wrote:
> 
> > Fastovsky is correct in concluding that dinosaur
> > diversity WITHIN the
> > Hell Creek Formation was not in decline up to the
> > K-T boundary.
> 
>   It is possible that lambeosaurs became extinct
> within Hell Creek time instead of immediately prior to
> it. Boyd made a case for the presence of Hypacrosaurus
> in the lower Hell Creek but AFAIK there is no evidence
> for it in the upper Hell Creek or the lower Scollard,
> which is equivalent.
>  
>  
> > That said, some workers have claimed that a Hell
> > Creek nodosaur went
> > extinct before the K-T boundary.  But considering
> > that ankylosaurids are
> > generally uncommon in the Hell Creek Formation,
> > there is a good
> > possibility that the proposed premature nodo
> > extinction may in fact be
> > only an artefact of sampling/collecting.
> 
>   A. magniventris apparently reached the K-T boundary
> in WY but Edmontonia might have disappeared over
> 300,000 years earlier.
> 
> 
> 
> 
>               
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