[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: avian flight



>Claws have completely inept shapes for this function, I'd say. <

They fit entirely within the size and location parameters of leading edge
protubernaces long since tested in wind tunnels.  A lot of those tests
included evaluations of ice accretions on the leading edge surfaces of
wings--which is as close to random shapes as you can come.  The significant
variables are >always< the spanwidth length of the protuberance, its
chord-length extension above the airfoil surface and its chord-wise location
on the airfoil.  If you think these measurements are "inept", I'd like to
know the basis on which you come to that conclusion.

>And claws of noticeable size coexisted with alulae in early
ornithothoracines such as *Sinornis*.<

What is a "claw of noticable size"?  The facts are that alula appear in the
fossil record only among feathered flyers that have reduced claws or reduced
alular digist.  Prototpteryx (Shang and Shou 2000) is, in my opinion, the
>most primitive< example of a feathered flyer with unreduced alular digits
>and< an alula, but even it shows obvious reduction in the manus claws
according to those authors.

>Confuciusornithids (snip) had quite some difficulties in slow flight and in
manoeuvering because they had no alula.<

I agree with you that that is indeed a testable---which I think would easily
be proven wrong with the right experimental set up. Alas...

Pat