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Re: Cladistic taxonomy (was Dietary factors)





T. Mike,
I agree with you on the imprecision of the term "bird", and people should be more careful to say avian when speaking in a phylogenetic context (I'm sure I have been guilty of doing this myself). A certain amount of precision is crucial to effective communication, and I think you are right to point this out. But I still believe purely cladistic classifications take precision to an extreme, and that phylocode will exacerbate that particular problem.
As for Cetartiodactyla, I would think you would embrace such a clade name. If traditional Artiodactyla is paraphyletic (and cetaceans are an exgroup), as seems to be the case, a new cladistic term like Cetartiodactyla is a good idea. If one redefines the paraphyletic term Artiodactyla to include cetaceans, that would be just one more term that has been unnecessarily appropriated and cladified (just as Osteichthyes and Reptilia were). Wouldn't you agree?
-------Ken
P.S. Eparctocyona is a term dredged up by Malcolm McKenna in his recent cladistic classification of mammals (McKenna and Bell published that book in 1997, if I recall correctly). I think the term Cetartiodactyla is vastly superior because it is immediately clear what major groups are included. I don't recall if they are exact synonyms or if Eparctocyona is slightly more inclusive. In any case, I would still prefer two separate orders, a semi-holophyletic Artiodactyliformes (containing a marker for whales) giving rise to a separate order Cetiformes. I will certainly never say whales ARE artiodactyls, but I have no objection to saying whales ARE cetartiodactyls. Now that's the kind of precision I do find useful. :-)
*******************************************************
From: "T. Mike Keesey" <tmk@dinosauricon.com>
Reply-To: tmk@dinosauricon.com
To: -Dinosaur Mailing List- <dinosaur@usc.edu>
Subject: Re: Cladistic taxonomy (was Dietary factors)
Date: Tue, 8 May 2001 23:32:18 -0400 (EDT)

On Tue, 8 May 2001, philidor11 wrote:

> HP Williams had, I thought, considered that:
> In effect, if a genus is more closely related to modern birds than
> _Archaeopteryx_, then it is considered a bird *in the scientific sense*.

"Bird" is often (although not always) equated with "avian" -- the
definition of _Aves_ is "the most exclusive clade containing
_Archaeopteryx_ and modern birds", not "all taxa sharing more recent
ancestry with modern birds than with _Archaeopteryx_". (Just wanted to
clear that up for any readers. I don't think the latter clade is named,
although someone did try to pin _Ornithurae_ on it unsuccessfully, IIRC.)

> Archie is part of the _definition_ of  birds.

This is the second time I'm making this point today; Archie is NOT part of
the definition of "bird". "Bird" is a vernacular term that means whatever
the body of English speakers at large determine it to mean. Archie is part
of the definition of _Aves_, a formal taxon which is not necessarily the
same thing as "birds".

"Avian". It's only one letter longer than "bird", and so, so much more
precise.

> Bas VanFraassen sez: you don't need clear boundaries to have a legitimate
> distinction; all you need is a clear case of the one kinda thing and a clear
> case of the other kinda thing.


This works for vernacular terms like "bird". Not a great idea in formal
nomenclature, IMHO.

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