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Re: pterosaur takeoffs



Matt (Alien4240@aol.com) wrote:

<This is probably a dumb question but what's a
furcula? I can't find it in any of my books. Thanks.>

  It's a wishbone -- more acurately, it's the avian
wishbone, formed by two forks of a single bone with a
ventral (downward) process called a hypocledium [hypo:
below, under + cledium: clavicle = below the
clavicle]; recent studies by Norell, Makovicky, and
Clark (1993) and Norell and Makovicky (1990, and in
press) on the nature of the furcula in dromaeosaurids,
and _several_ articles by others (I'll try to get a
full list out, several are _very_ accesible) suggest
that the dinosaur furcula (present as far back as
*Allosaurus*) developed from fused clavicles
(collarbones), and then developed a hypocledium,
present in an unnamed dromaeosaurid from Mongolia (see
Norell and Makovicky, 1999), then we get birds. Martin
or Feduccia (or one of the BAND crew; can't remember
the date) suggests the furcula developed as a single
bone and is not related to the clavicles in reptiles.

  Oh well.


=====
Jaime "James" A. Headden

"Come the path that leads us to our fortune."

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