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Re: alula

Norton, Patrick wrote:

> Philidor wrote, in part:
> eoalulavis, ..... the first with an alula,
> Pat wrote........I believe that the same function could have
> been performed by the unfused digits of more primitive fliers such as
> Archaeopteryx. By extending its digits outward and upward in slow flight,
> Archie could have created turbulence across the surface its wing the same
> way an alula does for modern birds,

Pat's right.  I suspect the feathered alula  would be more effective at
converting turbulent separated flow to turbulent attached flow than would a
nonfeathered alula. Either type could be equally effective at creating a
longitudinal vortex to inhibit the spanwise spread of separated flow.

> ..........expect the evidence to show that the evolution of a feathered
> alula to be
> closely associated in time with the formation of a carpometacarpus.

An intriguing thought,