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Re: Feduccia ORIGIN



From: Dinogeorge@aol.com

 > Retroverted hallux (articulating in a shallow groove on the second
 > metatarsal, distally on the palmar side) occurs in all theropods,
 > and only in theropods, at and above the common ancestor of
 > ceratosaurians and tetanurans. In almost all the larger cursorial
 > forms, however, the retroverted hallux is secondarily reduced and
 > points, in varying degrees, posteromedially.
 > 
I thought that might be the case.

Feduccia is off base again.  This clearly indicates that the
anisodactyl condition is ancestral for birds, and all other forms
found in living birds are derived.  Such radical changes in foot
structure can, in my opinion, only occur if they are adaptive, contrary
to what Feduccia says.

Feduccia *also* states he does not believe that theropods had aniso-
dactyl feet!. (He associates the retroverted hallux with perching -
which he may be correct about, but that just means that basal theropods
were arboreal).

swf@elsegundoca.ncr.com         sarima@ix.netcom.com

The peace of God be with you.