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Re: Palms in



Luis wrote:
Another interesting point is that Alan argues for the 'grasping. almost opposable freedom' of the third finger, while 1 and 2 are almost interlocked together. The range of mobility of fingers one an two is quite limited and could bend rather weirdly slightly backwards!. The second finger was possibly the bearer of feathers (specially in Archaeopteryx). Alan Gishlick considers Archaeopteryx ' hand virtually the same as Deinonychus. The rest of maniraptoran hands are just more or less variations of a similar system (that makes for Scipionyx, Ornitholestes, and so forth) perhaps in more primitive ways. Allosaurus do not have a semilunate as such, but Dan Chure showed an
articulated fossilized hand that bent curiously sideways... so Allosaurus might have been a very primitive maniraptoran.<<<

Dan Chure certainly appears to be right. In my paper at the Tate Conference I described how the carpal that is homologuous with the maniraptoran semilunate allows much the same sort of action, although to a much smaller degree than in maniraptorans. Allosaurus can also bend digits 2 and 3 slightly backward (as much or more than it appears Denonychus could) so this may not be as weird as you think. I'm not sure that any of this is indicative of a phylogenetic relationship closer than what has been hypothesized by Holtz, Padian, or others, but rather they were probably common adaptations plesiomorphic to the group that gave rise to maniratorans.

Scott
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