Re: Fastovsky vs Archibald

[don ohmes <d_ohmes@yahoo.com>]

>>> And that means scouring a point in
> time at a point on the
> earth and digging every piece of available
> information out of that
> place/time. <<< 

Oh, yeah. What he said. I'll put my money on that. If
you had your druthers, what would you rather have?
Comprehensive knowledge of a 1 hour afternoon time
slot, circa 65.7553656 mys BP, or a pile of bones
strung out over 10 mys of fuzziness to conduct endless
cladistic analysis on? Er, never mind, unfunded and
rhetorical question. 

What PB said.

--- Phil Bigelow <bigelowp@juno.com> wrote:

> 
> 
> On Sun, 26 Jun 2005 04:01:26 -0700 (PDT) Tim Donovan
> <uwrk2@yahoo.com>
> writes:
> > 
> > 
> > --- Phil Bigelow <bigelowp@juno.com writes:
> >  
> > > It is unwise to compare two different
> > > paleoecosystems (e.g., the upland
> > > Canadian formations  vs. the lowland Hell Creek
> > > Formation) 
> > 
> >   The Scollard and Hell Creek do not look like
> > different paleoecosystems. They had essentially
> the
> > same dinosaur taxa despite a somewhat different
> > environment, which may be significant.
> 
> 
> Before we can claim that the Scollard and the Hell
> Creek are similar
> paleoecosystems, we need to resolve a few issues. 
> Here are only a few
> (of many):
> 
> The Scollard Fm. may have been deposited far from
> the WIS. Some workers
> even claim that the Scollard, itself, had closed off
> the Seaway.  Others
> claim that the WIS was open all the way to the
> Arctic even into the
> Paleocene.  Take your pick.  But if the Seaway was
> closed off in southern
> Canada by Scollard time, then the climate would have
> been harsher than it
> was further to the south.
> 
> The Hell Creek Formation was deposited adjacent to
> the WIS, which
> moderated its climate.
> 
> Is the flora assemblage in the Scollard Fm.
> identical to the flora
> assemblage in the Hell Creek?  What about the
> diversity of
> non-dinosaurian vertebrates? Are they the same for
> the two formations? 
> How common are freshwater mollusks in the Scollard
> Fm.?  What percentage
> of the Scollard is overbank mud?  Is that percentage
> identical to the
> percentage in the Hell Creek Fm.?
> 
> Dinosaurs, alone, do not make a paleoecosystem. 
> Dinosaurs aren't even
> considered to be candidates for being keystone taxa.
>  Just because the
> Scollard Fm. and the Hell Creek Fm. had a roughly
> similar dinosaur
> diversity doesn't mean that the two formations
> necessarily had identical
> (or even similar) paleoecosystems.  One has to study
> the *entire* suite
> of life in each formation.  And I argue, even down
> to the bacteria in the
> paleosols, if it were feasable to do so.
> 
>  
> > >or times (late
> > > Maastrictian vs. Campanian), or both, and then
> draw
> > > conclusions about
> > > extinction based on that comparison.  
> 
> 
> >   This is exactly what some of the leading
> authorities
> > have been doing for many years e.g. Archibald,
> Clemens
> > and Dodson.
> 
> 
> Yes indeed.  And I don't think that approach is
> always wise.  These
> workers distill things down to just species (or
> genera) vs. time.  Sure,
> it's nice and tidy, and one can easily wrap one's
> mind around their
> conclusions, but it may not convey any *informative*
> information.  In
> contrast, I believe that a holistic paleoecological
> approach is needed
> when interpreting the disappearance of taxa within a
> formation or between
> formations..  And that means scouring a point in
> time at a point on the
> earth and digging every piece of available
> information out of that
> place/time.  A Gestalt approach to paleoecology is
> needed.  Dinosaurs are
> only the tip of the Hell Creek iceberg, and their
> relative
> paleoecological importance may be overrated.  And
> the Scollard Fm. can't
> be used as a surrogate for studying the Hell Creek
> Fm. (and visa versa).
> 
> What were the keystone taxa in the Hell Creek
> Formation?  Are they the
> same taxa in the Scollard Formation?  Were they pond
> scum, or worms, or
> lice, or a more complex type of life?  And if we
> don't know what to look
> at to answer that question, then perhaps we need to
> develop a whole new
> paradigm for studying fossil life within sedimentary
> formations.
> 
> 
> > See the latter's remarks in the extinction
> > dialogue chapter of The Complete Dinosaur. Dodson
> may
> > have erred when he wrote that nodosaurs and
> > lambeosaurs were gone by Lancian time but it is
> still
> > possible that they disappeared within Lancian
> time.
> 
> 
> "Possible" and "proving it" are two different
> things.  Migration away
> from the Hell Creek region or increased geographical
> restriction within
> the Hell Creek region are two equally parsimonious
> interpretations of
> that same data, and in theory they are both provable
> hypotheses.  But it
> is nearly impossible to identify an undisputed
> extinction horizon within
> a formation.  Absence of evidence is not necessarily
> evidence of absence.
> 
> All that we can say for certain is that, so far, no
> articulated nodosaur
> or lambeosaur skeletons have been collected from the
> upper part of the
> Hell Creek Formation.  We don't even have enough
> samples to correlate the
> known nodosaur occurrences with depositional
> environments.  So, any
> further elaboration or interpretation of the data
> is, at our current
> state of understanding the paleoecosystem of the
> H.C.,  like putting
> lipstick on a pig.  The lipstick might make the pig
> feel pretty, but the
> pig is still just a pig.
> 
> <pb>
> --
> 
> 
> 
>