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RE: Rahonavis; sickle claws




-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
Øyvind M. Padron
Sent: Monday, November 26, 2001 1:38 PM
To: dinosaur@usc.edu
Subject: RE: Rahonavis; sickle claws

>Despite Eric's comments: yes, sickle claws evolved more than once in the
>history of theropods.  _Noasaurus_ is most definitely not a maniraptoran
>(bird or otherwise), and has a sickle claw.<<
>
>* Having just drawn Noaosaurus's remains I must say I don't think you can
>really say Noasaurus has a sickle claw. It's much much wider and not thin
>like the 'killer' claw of dromaeosaurids (Ah, its nice to use their real
>name :) ).

In real life it was most probably covered with ceratine, making it sharp and
well defined as a "sickle claw" i would say

-DinosØMP

Now that I have time to respond to some emails...

Sharp does not equal a 'sickle claw'. The sickle claw of dromaeosaurids and
troodontids are laterally compressed or are thin. Noasaurus's claw is nearly
twice as wide for its size as is the claw of a dromaeosaurid. It is a THICK
claw, more like a pes 3 or 4 than a 2. To be a sickle claw, the lower edge
needs to be thin and nearly blade like, Noasaurus is not like this.

After doing illustrations of claws today even the curvature of the bone claw
does not relate, in some cases, as to the curvature of the keratin. The pes
claws of Archaeopteryx have shallow angle, but with the specimens that have
the impression of the keratin shows that it has a very sharply curved claw.
The fruit bat has a shallow bony claw, but an extremely curved keratin claw.


Tracy L. Ford
P. O. Box 1171
Poway Ca  92074