Re: Dr. Bakker, Dr. Horner, The 'Dino-Pandemic' & The Canard About Declining Dinosaur Diversity in the

[Phil Bigelow <bigelowp@juno.com>]

On Sun, 14 May 2006 11:01:59 -0700 (PDT) bucketfoot-al@justice.com
writes:

> Besides the fact that a detailed review of the
> fragmentary fossils at Hell Creek done several years
> ago by a paleotologist whose name escapes me right now,

This one, perhaps?

Sheehan, P.M., D.E. Fastovsky, C. Barreto, and R.G. Hoffmann. 2000.
Dinosaur abundance was not declining in a "3 m gap" at the top of the
Hell Creek Formation, Montana and North Dakota. Geology 28(6):523-526.


> Consider these points if you will (and be chastened not
> to throw around such thinly supported assumptions in
> the future ;>)
> 
> 1.  This 'Declining Dino-diversity' analysis is largely
> (solely?) based on the fossil record of Hell Creek
> (which itself may not support it upon a closer analysis
> as I mentioned above) - but Western North America was
> but a small SLIVER of the Globe 65 MYA...


An equally complete terminal-K section is the Lance Formation:

Lillegraven, J. A., and J. J. Eberle. 1999. Vertebrate faunal changes
through Lancian and Puercan time in southern Wyoming. Journal of
Paleontology 73(4): 691-710.

FWIW, it's probably not good idea to consider the H.C. and the Lance Fm.
the same ecosystem (although they do appear to be rather close in
character).

Although some taxa found at the bottom of the Hell Creek Formation are
not found (in an articulated state, at least) near its top, the
*evidence* for a diminishing dino diversity up-section is found by
comparing the H.C./Lance dino fauna with the dino fauna in the earlier
(Campanian) Judith River Formation.   If all that paleontologists had to
look at was the Hell Creek Formation, then they probably wouldn't see any
clear (unambiguous) decline in diversity.

And, yes, there was a *significant* loss of diversity between the Judith
River dino fauna and the H.C./Lance dino fauna.  All of that loss was
pre-imact.

 
> 2.  I believe (and correct me if I am mistaken, please)
> that outside of Hell Creek, there is practically no
> other major Cretaceous fossil site accessible (ie near
> the surface) covering the period of 65 MYA; therefore


There are quite a few H.C. correlative units from Mexico all the way up
into Canada that preserve the boundary.


<pb>
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