Message 2000-07-0002: Re: Stem-based taxon definitions

Sat, 29 Jul 2000 12:14:36 -0400

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Date: Sat, 29 Jul 2000 12:14:36 -0400
From: Kevin de Queiroz <Dequeiroz.Kevin@NMNH.SI.EDU>
Subject: Re: Stem-based taxon definitions

Jonathan R. Wagner wrote:

>This [wording] avoids the problem of potential polyphyly in the
traditional "X and all taxa sharing a more recent common ancestor with X
than with Y" phrasing, as well as avoids the slight ambiguity I see in
formulations involving the phrase "the most inclusive clade."

Perhaps I missed something.  I don't see how the first phrasing could end
up causing a name to be associated with a polyphyletic taxon, nor do I see
any ambiguity with the seond phrasing.  I can imagine that there could be
problems with either of these types of wordings if there are problems with
the specifiers (X and Y in the examples), but these problems would also seem
to apply to Wagner's proposed alternative phrasing.  

Kevin de Queiroz
29 July 2000


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