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Re: Rahonavis; sickle claws



Sickle Claws in Modern Birds

  Not just a few species have very larger second pedal digit claws, however, 
one must realize that
in _all_ birds, either the second or the first claw is the longest. In the more 
terrestrial birds,
it's usually the first (hallucial) whereas some terrestrial birds (have a 
larger second [seen in
sereiamas, cassowaries and, I believe, kiwis and moa]). Most predatory birds 
and perching birds
have subequal yet very large second and first pedal claws, and the second 
through fourth are
strongly recurved. The first is also strongly recurved in strigiform, 
caprimulgiform, and
falconiform birds, as part of the raptorial specialization.

  However, only one bird has been noted to have a particularly "extensible" 
second pedal digit,
and that's the seriama; they have been seen (I have, anyway) to have a second 
toe that can lift
off the ground. But no modern bird or even fossil bird has a particularly 
"predatory" and largest
second pedal claw, and the seriama's claw is not so recurved as to be a "true" 
weapon, and neither
is that of the cassowary, so they do not qualify as "sickles." I can suggest 
that no member of
Aves has a predatory sickle claw.


=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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