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Re: Archaeopteryx



In a message dated 6/15/03 9:37:07 PM EST, Dinogeorge@aol.com writes:

<< >Any< two organisms share a common ancestor, so this assumption is 
trivial. 
 What this (or any similar) definition of Aves presupposes is that (when, 
say, 
 defined as the common ancestor of Neornithes and Archaeopteryx) Aves doesn't 
 also include a whole bunch of organisms that one would rather not see in 
Aves 
 (such as, perhaps, oviraptorid dinosaurs, therizinosaurs, etc.). >>

Incidentally, considering that Neornithes includes all birds that are 
supposed to have only wing digits 2, 3, 4 whereas Archaeopteryx evidently has 
only 
wing digits 1, 2, 3, this particular definition of Aves might include all 
theropods down to Ceratosauria, the latest theropods known to have digits 2, 3, 
and 
4 (along with 1) in their manus.