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Re: Semilunates and the Digit-Homology Question



----- Original Message -----
From: "Jaime A. Headden" <qilongia@yahoo.com>
To: <dinosaur@usc.edu>
Cc: <kinman@hotmail.com>; <mickey_mortimer@email.msn.edu>
Sent: Friday, March 09, 2001 5:16 AM
Subject: Semilunates and the Digit-Homology Question

[...]

>   In the transition from a 1-2-3 to a 2-3-4 wrist, the
> semilunate contacting the first metacarpal would be lost or
> reduced, transformed (pisiform of birds?)

?
Either, I've been fooling myself for years about what my own wrist looks
like, or the pisiform is lateral, not medial, to be more exact, the bone at
the base of the underside of human wrists [in playing-the-piano position],
proximal to metacarpal V. No nonavian dinosaur has this AFAIK, and I'm quite
sure birds have only the semilunate (1 + 2), distal carpal 3 (Hinchliffe's
"Element X", which he identified as a possible pisiform), radiale and
ulnare.

> , or not there to begin
> with. Thus the carpal would be either the single 2, or even 3,
> or both together, which would seem as possible, as the shift to
> ectaxony in birds would neccesitate a shift in the primary
> distal carpal. Now why is another matter.... :)

You say it.

:-)