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Re: Some thoughts on AVES



In a message dated Thu, 1 Nov 2001  7:57:03 PM Eastern Standard Time, "Ken 
Kinman" <kinman@hotmail.com> writes:

> (like those which divide therapsids 
> and mammals).   Yes, a character-based taxon---do I hear booing in the 
> cladist camp?  

You know what happens when you assume, don't you?

I, for one, am not at all averse to apomorphy-based definitions, as long as 
certain protocols are followed.  

A definition for Mammalia along the lines of "the first organism to possess 
three auditory ossicles homologous to those of living mammals and all of its 
descendants" would be absolutely lovely, as far as I'm concerned (since it both 
captures exactly a traditional conception of Mammalia and ensures that the 
group thus defined will be monophyletic).

However, there is no way that defining mammals in this way could somehow make 
them stop being therapsids, theropsids, amniotes, tetrapods, craniates, etc., 
etc.

--Nick P.