Re: Confuciusornis sanctus

["Patrick Norton" <ptnorton@email.msn.com>]

 Dan,

I'm responding off list since this appears to have become a discussion just
between the two of us.  You asked:

>??  Isn't the alula a modified digit I?<

Not in a strict sense, since evolution did not modify a finger to become a
tuft of feathers.  From an evolutionary perspective, what happened (IMHO) is
an example of exaptation---one structure (feathers) being opportunistically
co-opted through natural selection into taking the place of another
structure (moveable, clawed fingers) to perform the same flight related
function.  It's interesting to note that this did not occur in the
non-feathered flying vertebrates (pterosaurs and bats), which both retained
functional manus claws on the leading edge of their wings. I suspect these
perform(ed) a similar flight function in those animals as well.

I'm not asking for you to give away any secrets, but are you working on
something along these lines? I have a couple ideas for some very very simple
models that I might make this summer to test my idea.

Cheers,

Pat