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Re: Origin of Birds



> So, to summarise, ordinary cladists are concerned with ancestors, as are 
> evolutionary taxonomists.  Pattern cladists probably aren't.  However, the 
> vocabulary of evolutionary taxonomy allows assertions like "dinosaurs are 
> descended from thecodonts", whereas the cladistic equivalent would be 
> "dinosaurs are archosaurs".

     Not entirely true; evolutionary taxonomy is happy to recognize
monophyletic groups, and Archosauria is a taxon that was around well
before cladistics (and for that matter, evolutionary taxonomy as it is
currently practiced). Evolutionary taxonomy would be happy to say
"dinosaurs are archosaurs." "Thecodonts", if we choose to recognize them
as a particularly useful formal paraphyletic taxon, would be a
paraphyletic subset of a monphyletic Archosauria, so both statements are
kosher by evolutionary taxonomy, although only the second would be
accepted by cladisitcs.       

LN Jeff
O-