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Re: Science feather strength debate



David Marjanovic <david.marjanovic@gmx.at> wrote:


> Baffling though it is, they were both apparently unable to lift their arms
> above shoulder level. That kinda sucks.


Yes, it does.  Especially if you want to flap your arms.

Senter's (2006) biomechanical interpretations of the scapular
orientation are similar to those of Carpenter (2002).  The latter also
argued that the orientation of the shoulder socket (glenoid) in
_Unenlagia_ was no different to that of other non-avian theropods
(contra the original description).  Apparently there is a great deal
of disagreement on this point.  In a similar vein, Carpenter (2002)
claims that the forelimb of _Deinonychus_ was incapable of avian-style
folding.


>>  Then there's the matter of the keel - absurdly small in
>>  _Confuciusornis_, non-existent in _Archaeopteryx_.
>
> Bats have no keel at all...


Bats have a small keel.  Also, it's my understanding that birds and
bats have different muscle arrangements to work the wings: mostly
ventral in birds (hence the need for a large ventral attachment site),
whereas bats use both dorsal and ventral muscles, which share the
load.


Cheers

Tim