RE: Archaeopteryx flight

["Tracy L. Ford" <dino.hunter@home.com>]

-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of Tim
Williams
Sent: Tuesday, September 04, 2001 11:38 AM
To: david.marjanovic@gmx.at
Cc: dinosaur@usc.edu
Subject: Re: Archaeopteryx flight


>>By a "perching foot" I suppose you mean (in anisodactyl perchers) a pes
that
has a reversed and distal hallux that is opposable to the other three digits
allowing a greater degree of prehensile ability in order to grasp branches.
A specialized perching foot allows a bird to adopt a vertical "hands-free"
posture when sitting on a branch.  This is a very useful thing for a bird to
be able to do, since (with one notable exception) the anatomy of modern
birds is entirely "hands-free".  At least in the sense that the digits on
the manus are not free and useful for grasping.

Lack of a specialized perching foot would *not* prevent _Archaeopteryx_ from
climbing trunks or branches, since it still had a mobile and fairly
prehensile manus tipped with nice sharp claws.  Ditto for the pes, though
this probably had less prehensile ability than the manus.<<

Important point here, "hands-free". If they still used their hands while
climbing then they wouldn't need a reversed hallux.


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