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Re: Maniraptor arms?




Date: Sat, 12 May 2007 00:56:08 -0400

thanks for the prompt reply.

On Friday, May 11, 2007, at 10:30 PM, Anthony Docimo wrote:

When a maniraptoran moved its arm, did the two arms move in sync with one another, each a mirror image of the other? (since it likely wasn't in sync with the legs, as quadrapeds are)

I got the idea for this question by thinking of how birds fly by flapping their wings largely in sync with one anther -- opposed to how a primate can hang by one arm, while eating with the other.

thoughts?

Well, I'm not sure how one would test for arm motion timing,

just a thought -- would there be any difference in the sockets, to tell the difference between alternating and paired limb movement? ie,
* right rear leg & left fore leg....left rear leg & right fore leg...repeat


* right rear leg & right fore leg....left rear leg & left fore leg....repeat

*right fore leg & left fore leg....left rear leg & right rear leg...repeat

Whether the arms were used in synchrony or out of phase when grabbing for prey, obstacles, etc. would seem to matter primarily on what the animals were deploying the arms to do. A predatory stroke would, for example, probably be synchronous against small prey (grabbing) and asynchronous when utilized to harm larger animals (slashing blows).

good point.

Birds actually do not always deploy their wings in synchrony. They flap in synchrony under the most common conditions (leaping launches, level cruising flight, etc)

this is what I had in mind. after all, even giraffes sometimes vary how they use their legs.


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