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Re: Science feather strength debate



> I'll only add that in several papers published in the 1970's, John
> Ostrom proposed that _Archaeopteryx_ could not fly. He even
> stated that the position of the glenoid prevented the humerus from
> being raised above the shoulder.

 I wonder whether Archie had enough flexibility in the elbow and wrist
 to compensate for this? Could it not have utilised a flight stroke
 more like that of modern bats, with a lot of flexibility in the
 various wing joints, rather than having the more stiffened wing
 structure seen in modern birds?

I'm not sure what you mean. In what way do bats have "a lot of flexibility in the various wing joints"? I only know of one thing they can do that birds can't, and that's to supinate & pronate the forearm. (Hummingbirds compensate by rotating the entire wing in the shoulder joint.)

Bats use the movements that a human would use to imitate a wingstroke. For instance, the functional joint between wing and body isn't the one between humerus and scapula, it's the one between clavicle and sternum. Hold your arms up, wave them back and forth, and pay attention to what your collarbones are doing.

Bats cannot move the wing up by rotating the forearm upwards at the elbow any more than we can, and neither was Archie capable of such a unique feat. We could do that at the wrist, but I'm not sure bats can, and that's much too far out along the wing anyway; I very strongly doubt it for Archie, too.