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Regarding propatagia and brooding dinos, PTJN wrote:

<<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

Good points, well taken, but:
    Are you saying that (1) above is not true for flight as well (two
solutions, that is)? Ockham RIP.
    Tom Hopp