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Sickle-claws and retraction (was Re: New Velociraptorine)
Sam Girouard wrote
> Really? Ever since Bakker's restoration of Deinonychus back
> in the 60's it has been unanimously assumed that all "sicle-clawed"
> theropods [....] held their "killing claws" clear above
> ground. However, I object to this mode of restoration for several
> I have even read an account of a rhea killing an Australian boy by
> slashing his throat with one such claw.
One of these two was a long way from home. Rheas are South American
birds. The perpetrator may have been a cassowary, a ratite from
Australia and New Guinea renowned for its filthy temper.
> Third, the wear experienced by normal locomotion would have been
> miniscule compared to repeated contact with bone while dispatching
> prey (if the claw were even used in this role at all).
Not if the sickle-clawed theropod struck at the soft underbelly. A
nice, swift evisceration, and down goes the prey.
[ Are we being a bit too mammalocentric here? Would an animal with a
rib cage extending all the way to its pelvis have a "soft underbelly"?
-- MR ]
> Fourth, I do not know of any articulated theropod feet that show any
> evidence of a retracted claw. This probably doesn't provide a good
> indicator, after all the animals had died and dried, but negative evidence
> beats no evidence at all.
Like the lack of didactyl footprints, absence of evidence is not
evidence of absence.