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Re: Pygostyle



>It has been my experience that everything can be used to argue anything in 
>this field, and therefore nothing has any meaning. Pygostyle schmygostyle. 
>Think whatever you like; it makes no difference.

I'm a bit startled by the tone of this response.  I was not, I think,
engaging in chop-logic or trying to bait George or anyone else.  However, I
would greatly appreciate views on the specific points I raised.  To be more
specific:

a) If the pygostyle has been retained from a flying ancestor of
oviraptiorians, why is it missing in basal members of the line like
Caudipteryx?  Or are you arguing that Caudipteryx is not basal but
represents a derived loss of the pygostyle, which would have been found in
genuinely basal members of the group?

b) Does the pygostyle really represent an adaptation to flight?  I know it
serves that function in modern birds, but would a flexible tail with fusion
of the distal vertebrae be of any aerodynamic use?

c) Is the pygostyle in oviraptoria homologous with that in modern birds? If
so, what does that say about the phylogeny of these lineages?

It strikes me that these ought to be answerable questions, and that they
bear directly on the question of whether the pygostyle can be used as
evidence for or against BCF.  My own initial view was that, for the reasons
I stated, it could not be used for BCF, but of course that does not
disprove or discredit BCF- it only implies that the pygostyle was a later
development, or perhaps a serise of parallel developments.
--
Ronald I. Orenstein                           Phone: (905) 820-7886
International Wildlife Coalition              Fax/Modem: (905) 569-0116
1825 Shady Creek Court                 
Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@home.com