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Re: Velociraptor footprints



Sam Girouard wrote:
> 
> Extant ratites, that have been known to kill even humans with their inner
> digit's claw, do fine without carrying their second digit off the ground.
There isn't a comparison here.Ratite claws are VERY different in
shape.They have to be because they aren't held off the ground.No extant
cursorial animal that I'm aware of has a pedal claw shaped like a
dromaeosaur claw.The only similar claws I can think of offhand are those
of raptors (which of course aren't ground based runners)and felids(
which retract the claws).If this holds out, then we have no extant
precedent for a cursorial animal with similar claw shape (not to go into
claw proportion)that >doesn't< retract or keep said claw off the ground.
But the evidence suggests that dromaeosaur claws >were< probably done
so.They could be hyperextended.The corresponding met. is shorter than
the others.And (a very important point)as I stated earlier the very
proportional >size< and >shape< (sharply curved,sharply pointed,thin and
bladelike)of the claws strongly suggests that they WERE NOT subjected to
constant contact with the ground like the other claws.
> It isn't exactly hard to imagine them lifted either.Even
> >in Tyrannosaurus the two "outer" toes are larger and stronger, and,
> >correct me please if I'm wrong, were the principal weight bearers.
> 
> But this is a >cursorial< adaptation, for speed.
This has little to do with my point.See my original posting.
> [snip]
> 

> 

> 
> This is all good speculation, but until even ONE shred of physical evidence
> exists, I will remain unconvinced. Of the tens of thousands (hundreds of
> thousands?) of small theropod tracks that have been documented, NOT EVEN ONE
> unambiguously shows a retracted second digit. Period. Occam's Razor tells us
> that small theropods simply didn't carry their second digits off the ground.
> 
> Sam
How is this so?Not one trackway shows (unless I'm way behind, which is
possible >G<)a dromaeosaur trackway with this distinctive claw down
during movement.AND we have no modern precedent to assume that animals
that do not retract them in some way develop claws of this nature.YET we
have skeletal remains that show a strangely specialized foot .A second
digit that seems to have evolved to hyperextend and has a unusualy short
metatarsal.On this foot we have (in some species) a claw that seems too
large and bladelike to have been in constant contact with the ground.So
"Occam's Razor" would tell us that these theropods did indeed carry
their second pedal digits >off< the ground.-----Speculation as usual,
Sean C.