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Re: four winged Archaeopteryx

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

<There is embryological evidence against this. Extant birds have 18 to 23 tail
vertebrae. It's just that most of them end up in the synsacrum and the
pygostyle; the latter consists of lots of _small_ vertebrae.>

  I am aware of this. The juvenile *Cathayornis "caudatus"* even shows the
separation of the pygoistyle into its segments (somewhat). However, reduction
from the distal end towards the base DOES occur through theropod evolution, and
the fusion of caudals occurs in the distal end, and through reduction of the
tail even without synsacral incorporation of the urals ("free caudals"). This
would argue that in "small-sacralled" birds the long tail was reduced before
incorporation, while in "big-sacralled" birds, the tail reduction has already
occured as the sacrum becomes more incorporating.


Jaime A. Headden

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

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