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Re: ptero endothermy



Dave Peters (davidrpeters@earthlink.net) wrote:

<In science, I am led to believe, the best explanation at the time is the
working explanation. If a better one comes along we should jump from this
wagon onto that one.>

  When I first heard that science prefers the shortest, simplest
explanation, I beleived it ... until I saw more complex arrangements and
directed challenges to that tenet in the fossil record, so I realized
Occam's Razor cannot be applied literally to a conclusionary subject, but
only to the methodological subject to arrive at a conclusion. Hence
Doyle's addage: "when all other data has been removed, what remains, no
matter how impossible, must be the answer."

  This is applicable variously. In Dave's case, I do not disbeleive the
prolacertiform argument, but rather the presentation of this as fact.
Doggedly applied "fact." How can we be objective and scientific when we
are advancing an hypothesis with doors closed off in our heads?
Personally, it looks strong that pterosaurs are prolacertiforms; rather
Dave has also advanced nearly every other Triassic "parareptile" as a
pterosaur ancestor, and no one has yet adopted this. This does mean Dave
is the odd man out on the matter, right or wrong, and I think it warrants
a critical review. However, others have applied many of these taxa as well
in cladistic phylogenies, and derived at different phylogenetic positions
for some. Drepanosaurids may be more basal than Archosauromorpha, for an
example, beyond preolacertiforms, archosaurs, *Euparkeria,* and maybe
close to the base of Diapsida.
 
<The pelvis deal is old news. Why it hasn't been accepted is (as you
already know from your readings of Martin, Feduccia, Jones, Ruben, etc. in
another well-known squabble) academic politics.>

  We did already hear arguments for an alternate, repeatable argument
about the elongate ilium's function, as in anurans, to reduce stresses
through the axial column? Anurans stress their spines when leaping, and
pterosaurs do by flying, another reason it appears that primary fliers
like birds have such whopping huge ilia. Therefore, the data implies that
morphological similarity may not be phylogenetic similarity, and this is a
good place to start testing.

<If you only have tomatoes to throw, please don't throw any more. You're
one of the smartest scientists of your generation. Tear down the
prolacertiform hypothesis or any part of it. That's your challenge. If it
is possible, I think you are the guy to do it.>

  Well, all compliments aside, if appreciated, I would actually like to
see Dave do this. I could, but I lack the resources to investigate the
morphology of pterosaurs and the other diapsid kin given stock, and my
interpretation of preserved material and investigation of this material is
much narrower.

=====
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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