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Re: another FAQ?

>From: Tom Holtz <tholtz@geochange.er.usgs.gov>
 > > What other reclassifications have I missed?
 > Trachodon (in the sense of the skeletons at the American Museum of Natural
 > History at NYC)
 > -> Anatotitan

This one is complicated enough to deserve more comment.
It also involves:
Anatosaurus -> Edmontosaurus + Anatotitan

Until recently most of the specimens popularly called Trachodon
(such as the AMNH skeleton) have been considered to belong
to the genus Anatosaurus.  However, a recent study has shown
that most of the species assigned to Anatosaurus are effectively
identical to Edmontosaurus, and have been transfered to that
genus.  The set so transfered includes the type species of
Anatosaurus, which, by the rules, makes Anatosaurus a junior
synonym of Edmontsaurus.

However, one species, "Anatosaurus" copei, is quite different
in morphology, with a flatter, broader face.  It does not fit
in Edmontosaurus.  The result of the above was to leave this
form without a generic name, so a new one had to be formulated
for it, hence - Anatotitan.

[Note, I think this change was overdue - the similarity of most
species of Anatosaurus to Edmontosaurus is so obvious even I had
noticed it; and the distinctiveness of Anatotitan copei is also
extremely obvious]

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

The peace of God be with you.