Re: Apomorphy-based definitions (of mammals [...])

["Ken Kinman" <kinman@hotmail.com>]

    Yes, I was being imprecise last night, and David was right to point 
this out (shame on me).  Total loss of the last vestiges of what was once 
the reptilian jaw articulation occurred at the Hadrocodium stage.  However, 
the mammalian jaw joint had long since taken over as the functional jaw 
joint.
    That the latter had occurred in Adelobasileus can only be inferred at 
the present time, so the definition was made more precise with its 
remarkable "incipient promontorium".  Once we have more complete fossil 
material of Adelobasileus and/or its closest relatives, a more precise 
definition will be possible without having to invoke controversial 
inferences (forced on us by incomplete material).
    So getting back to Aves, this is why I am so concerned that the 
definition of the "true" semilunate be made more precise by including 
evolutionary transitions in one or more of the adjacent bones.  This is what 
I mean by learning from the mammalian equivalent, and try to do it better 
with Aves.  Such a precise definition would presumably even convince the 
most staunch Feducciaries that birds clearly evolved from coelurosaurian 
dinosaurs (but bringing that debate into sharper focus would be just icing 
on the cake, not the major reason for doing it).  I have given this a great 
deal of thought, and I'm convinced it is the best way to proceed (regardless 
of whether you want to call Aves a major "Class" or a major "Clade"---to a 
cladisto-eclecticist, Aves is both a Clade *and* a Class).
             ------ Ken



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