Re: Maniraptor arms?

[Anthony Docimo <keenir@hotmail.com>]

> 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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