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Re: Apomorphy-based definitions



David Marjanovic (david.marjanovic@gmx.at) wrote:

<The PhyloCode even makes a proposal to get around that problem. Just word
> the definition as "the first organism which had a 'true semilunate'
[detailed descriptions and illustrations!] homologous to that of *Passer
domesticus* [or whatever bird] and all its descendants". :-)>

  Except that you now have to figure out what morphology known in theropod
wrists is homologous to the passeriform carpal, whether the carpal complex
itself changed between *Archaeopteryx* and *Passer*, or evedn if all
carpal morhologies within *passer* itself are exactly the same to count.
One then chooses a specific specimen or series to refer to to even know
what the morphology developes as... and a detailed embryonic study in
dinosaurs to compare to. Difficult? Drop apomorphy-based definitions...

=====
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.

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