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Re: Evidence For a Feathered Velociraptor...



Graydon said:

I think it's fair to say that quill knobs are the preferred
biomechanical solution for transferring forces from wing feathers to the
skeleton in extant flying birds.

I'm not so sure it's the "preferred" solution as much as it may be the "best available solution." Keep in mind that two different solutions to this problem can seen in most any bird today. The flight feathers that are most perpendicular to the extended wing (the first and secondary remiges) are the ones embedded directly into the ulna via a "quill knob", while the shafts of the more distal primary remiges (those that tend to be most parallel to the extended wing) are secured to the carpometacarpus by resting in a groove and anchored by tendons (sans quill knobs). It may be that evolution eventually settled upon different solutions for transfering to the skeleton the forces generated by the secondaries (which mostly generate lift) versus those of the primaries (which mostly generate thrust), based on their inherited biomechanical orientation rather than just aerodynamic optimization. After all, evolution had to work with what it had. There may well have been other solutions too, earlier in the process, which we haven't yet seen.


PTJN