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Re: So-called Sickle Claws



In a message dated 97-08-28 04:13:44 EDT, vonrex@gte.net writes:

> a foot from a wild upstate New York Turkey...
>  On all the toes (which retain
>  their keratin sheaths) the skin and pad extend way down and onto the
actual
>  claw itself.  That is, the claws protrude somewhat from within a skin/pad
>  covering.  Now since we are constantly evoking birds as the best living
>  anaologs for dinosaurs, I imagine the dromaeosaur foot was probably
>  similarly adorned- bringing both skin and pad going right down to the ends
>  of the toes and at least a bit further onto the claws themselves.  

I have friends who will wince at my saying this, but my favorite
representation of a dromaeosaur foot is John Sibbick's from David Norman's
_Illustrated Encyclopedia of Dinosaurs_ (pp. 56-57).  This does show toe pads
under the three central toes and skin around the bases of all the claws.  It
also shows the pad under phalanx II-1 resting on the ground; but, with the
joint between phalanges II-1 and II-2 fully hyperextended, the falciform claw
is held well off the ground.


>  My main gripe is that I almost never see that toe in any but the most
>  retracted postion it could ever possibly assume...No matter what position
the foot
>  is in!

I will agree that the second toe was probably not always hyperextended when
the foot was off the ground--unless, of course, there was some sort of
ligament to keep it there.


>  look at the
>  same toes on the Dromaeosaur mount in the same book... bent straight up in
>  the air.  Doesn't that look a little weird?

I agree that this is certainly not necessary to keep the claw clear of the
ground.

What I disagree with strenuously is the contention by some people on this
list that there was nothing special about the claw on the second toe, that
its size and importance have somehow been overestimated, or that dromaeosaurs
habitually walked with the tip of the second-toe claw on the ground.

NP