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Re: New dinosaur diversity articles



Tim Donovan (uwrk2@yahoo.com) wrote:

<Lambeosaurs appear far less diverse in North America by the early
Maastrichtian. Hypacrosaurus is the only post Campanian NA lambeosaur
genus known AFAIK. * Centrosaurines were also down to one genus by
then-Pachyrhinosaurus-and were totally gone by the late Maastrichtian.
Saurolophines had also vanished by then.>

  Tim seems to have an inordinate fascination with lambeosaurs, for some
reason. Maastrichtian hadrosaurs in North America did not actually
decrease in diversity, as _hadrosaurines_ INCREASED in species identified
in the Campanian and into the Maastrichtian. An argument may then be made
that labeosaurines, however "beloved" they may be for their visual and
anatomical development, may have been "mastered" by the
edmontosaurs/anatosaurs of the North American continent.

  As for Tim's ankylosaur data ... why doesn't he offer his references? I
would dearly like to see a set of refs put down as the posts continue to
attempt to refute published data without sounding like anecdotes.

  I also am fascinated by the mistaking of the preservation record and
taxonomy's naming of species that may be "valid" or "invalid" by others as
an accurate assessment of species diversity, declining populations, or
whatnot. This is a REALLY tricky issue, and for the most part, the actual
conclusions of most papers on the subject do in fact note this as the
"refutation" to their work. Tim might heed these cautions, lest he begin
to beleive otherwise.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


        
                
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