Re: So-called Sickle Claws

["Peter Von Sholly" <vonrex@gte.net>]

My dear NP-  The Sibbick illustration you cite shows the articulation
between the first and second phalanges on that toe at about a ninety degree
angle, (but at least being a weight-bearing toe!).  My contention is that
this is far back as they could possibly retract.  There is no room for
"give" if the claw took any impact.  Greg Paul pulls the claw so far back
in Predatory Dinosaurs that it actually appears to rest against the
metatarsal- on both feet even when running.  It seems that the bones would
simply come apart if pulled that far.  Anyway, why would the animal keep
its toe that way all the time?- Wait! Don't answer that.   Looking at the
drawings from Ostrom , In Dinosaura (p.275); those phalanges are more or
less shown in that same orientation (leading me to speculate that this
drawing is probably what Sibbick was using as reference).  I have done a
tracing of that drawing, changing absolutely nothing except rotating the
second phalange down about another eighty or so degrees and sketching in
the outlines of heel and toe padsunder the foot.  It looks swell.  It looks
logical.  It looks like it would work fine for walking and not compromise
the big claw's efficiency at all.  I wish I could show you the drawing...
The Velociraptor foot cast I have seems to show ample space on phalange one
to accomodate a wide swing of phalange two, again the ninety degree angle
being the most extreme position possible.  
Also, the tip of the big claw appears to be blunt.  No doubt you will
conclude that it was simply preserved that way; broken.  But maybe it
wasn't preserved because it had been dulled or broken off in life through
usage.  
If a ligament held the claw up that far all the time, it would be a
ligament mightily stretched anytime the animal wanted to flex that toe
much.  Also, looking again at Sibbick's illo, he seems to have left the
"peduncle" or whatever you call it, naked.  Wouldn't that bump on the
bottom of the inner curve have been attached to a tendon?  Or to something?
Yes, it's a bigass claw, yes it's quite distinctive.  But I must insist I
feel it has been misunderstood and misrepresented nonetheless (not
necessarily with evil intent) for the express purpose of making the animal
(Deinonychus, that is ) seem more outrageous, more special, more newsworthy
etc.  Sorry.

----------
> From: NJPharris@aol.com
> To: vonrex@gte.net; dinosaur@usc.edu
> Subject: Re: So-called Sickle Claws
> Date: Friday, August 29, 1997 12:31 AM
> 
> 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