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Re: New Velociraptorine
Mickey Rowe wrote:
> [ The reason such a
> ligament is useful is that it maintains force with a much lower
> energy requirement than an equivalently sized muscle.
> ... it's not clear to
> me that Russ was even thinking about ligaments when he brought up
> the subject... I'll step aside now and let Russ argue it if he so
> chooses. -- MR ]
Mickey's editorial comments on Jeff's message were on target as usual.
It would be a ligament retracting, muscle extending, to minimize
energy--certainly not v.v.--so extension muscle conditioning remains
a problem if you believe the claw was not locked.
Although I'm familiar with the role of the nuchal ligament
(that's where the predicted nephrology came from) it wasn't
obvious to me to what extent a ligament could replace a muscle?
[ Now I'm missing something... what do kidneys have to do with the
price of ligaments in Chinese theropods? I think you meant
"taphonomy" rather than "nephrology". -- MR ]
BTW, one likely design for a locking joint would consist of a
series of deep grooves (height/width ratio near 1) perpendicular
to the direction of travel along both mating sides of the joint.
In vivo they would be separated by a stiff but deformable membrane
that would allow relative motion at low internal joint loadings,
but the membrane deforms into the grooves, allowing the grooves
to interlock, when extensors and retractors are simultaneously
activated. As I proposed, locking the claw would allow the claw
to be driven into prey scythe-like.