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Re: "Flight theory has legs"

John Conway wrote:

Chris did not look at hand claws (and made that clear) - the predatory function of the hand claws in many species would have clouded his results at this early stage.

I'm wondering aloud here.... I think it's fair to say that the predatory function of hand claws for big-ass long-armed dromaeosaurs like _Velociraptor_ and _Deinonychus_ is undisputed. However, for smaller critters (e.g., _Microraptor_, _Sinornithosaurus_, _Archaeopteryx_) the role - if any - of the hand claws in prey capture is a little more controversial.

The hand claws of basal deinonychosaurs and basal birds may share a trend *away* from predation and toward scansorial/arboreal climbing. (BTW, I recognize that these functions are not mutually exclusive). Deinonychosaurs and basal birds were equipped with a formidable sickle-claw on the feet - which appears to be primitive for the Deinonychosauria+Aves clade. The sickle-claw might have been the weapon of choice when dealing with small prey, rather than employing the feathered forelimbs for this messy task.

After talking to him at length about his thesis, I'd have to say that his position on the origin of flight is somewhat more complex than the article would suggest.

I suspected as much - the media has a tendency to "dumb-down" the results and conclusions of in-depth analyses and research.

He is also looking at the possibility of a functional split that would allow the hand and foot claws to specialise for different tasks.

Sounds like a brilliant idea. Can't wait to see the details.




Timothy J. Williams, Ph.D

Department of Biophysics, Biochemistry and Molecular Biology
Science I Building
Iowa State University
Ames IA, 50011

Ph: (515) 294 7071

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