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Subject: Re: (intentionally left blank?)
The original title was pygostyle but that mail bounced back.
but I'll yield to the aerodynamic experts on this point! >Nonetheless, I
think you could use the pygostyle-bearing oviraptor to >argue the exact
opposite of what George is suggesting.
That is exactly was what it my mind. The primitive forms have long tails,
the derived ones have pygostyles. Thus unless one forms a sister grouping of
Pygostyled birds with Oviraptorosaurs- which would mean many more
homoplasies, the pygostyles are convergent. But all the same it is a
remarkable convergence. Given the convergences in other forms such as the
troodontids and Avimimus there may be some truth in "birdhood" being a
likely state due to constraints imposed on the material available for
natural selection. It would probably make an interesting thing to compare
the regulatory elements of the posterior hox genes in living birds and
crocodiles as a start to understand this issue.
I wonder what the animal behind the Protoavis skull was ? definitely a bird
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