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Re: Science feather strength debate



2010/11/16, Tim Williams <tijawi@gmail.com>:
> I'm ashamed to say I don't have the abstract - could you or Scott or
> somebody post it here?  This might help to clear up your statement "
> it seems there are remiges, but very small and only on the distal half
> of the humerus".  If these remiges are on the humerus... then aren't
> they tertials?
>
He, if you are ashamed, what is there for the less informed of us? ;
). Good luck I used remiges to avoid the use of tertials, which as you
indicate below, is problematic. I think it should be understood that
they had tertiaries, but very short ones and restricted to the distal
part of the humerus. The way I understood the abstract, there he says
the tertiaries gradually reduce proximalwards, so that near the
humeral midlenght they shoud be too short.

> What we are debating here is if _Archaeopteryx_ had remiges along the
> humerus, or if the remiges were attached only to the ulna and manus.
> If the latter, then these distal remiges might have been used not for
> gliding efficiency, but for control of body position during brief
> descents.  This is the central thesis of the "Pouncing Proavis" model,
> which proposes that the ancestors of birds used proto-wings for
> aerodynamic control during ambush attacks that targeted terrestrial
> prey, launched from rocks, ledges, or small trees.  This control was
> initially drag-based, but became more lift-based as the forelimb
> feathers became larger, stronger, and asymmetrical.
>
But, I think control in the latter case, if there is lift, may be
related to some kind of glide/flight, isn't it? In any case, the
control bay not be only useful in occassion of predation, which would
require a very fine control, but also in other occassions, such as
falling into the preferred substrate and avoiding to fall in dangerous
areas. Deciding between these alternatives seems like a difficult goal
to achieve scientifically at this point. In any case, both seem as
good abilities for a predator (if they were actually predatory) living
in places with great differences of height.