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Re: PAGATIA DO NOT MEAN VOLANT ANCESTRY



In a message dated 8/24/98 1:10:08 PM Eastern Daylight Time, TomHopp@aol.com
writes:

<< Incredible.  Just when I thought brooding-came-first had run out of ways to
 explain the evolution of the wing, along comes the above.>> SNIP <<Now I
 have gone back to note the possible role of the propatagium, and voila.
Here's the point: if primary (hand) and secondary (forerarm) feathers existed
on Oviraptor, they would have covered all of the eggs EXCEPT-- those that
would be covered by a propatagium.  Cool.>>

Your conclusion being that the propatagia evolved to assist in brooding?  Here
are two problems with that conclusion:

1) It demands two entirely different solutions to ONE problem in ONE animal--a
flap of skin on the leading edge of the arm and extended feathers on the
trailing edge?  If --as the BrCF theory suggests--all that's need is something
to provide cover for the incubating eggs or the brooding chicks (let's not get
into these different functions again), why not extended feathers on the
leading edge of the wing?  Or why not a flap of skin on the trailing edge?
Why TWO entirely different solutions--one for the front and one for the back?
Makes no sense to me.  Ockham would roll over in his grave.

2) A flap of skin between the shoulder and the wrist is NOT homologous--in any
sense--to the complexly muscled propatagium of a bird.  The evolution of the
avian propatagium is clearly complex and involves extensive realignment of
wing musculature in association with the fusion of the carpometacarpus.  It
was not simply an umbrella.  A simple flap of skin would have served that
purpose.