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Date: Thu, 03 May 2001 22:30:05 -0700 (PDT)
From: "Jaime A. Headden" <qilongia@yahoo.com>
To: PhyloCode@ouvaxa.cats.ohiou.edu
Subject: Re: [conflict between monophyletic taxonomy and rank-based classification]
Ken Kinman (kinman@usa.net) wrote: <In many cases, the well-defined clade is not only well-defined but distinctive enough that it has often been raised to a higher rank. One such an embedded clade is Aves which was so distinctive that even primitive peoples paraphyletically removed it from Reptilia. Not consciously of course, but this is how the human brain normally classifies, at least when it hasn't been conditioned to believe that paraphyly is something unnatural.> For some few thousand years, primitive peoples thought that birds were "angelic" beings, supernatural, bridgers of worlds between thought and death, life and darkness, etc. Ancient concepts of birds were to demonstrate that although they exist, no one knew _what_ they were. Not even Linnaeus "knew" what they were, and placed them into a group (Aves) that was clearly a member of the vertebrate "phylum". Further authors have bridged the gap by attempting to see what other groups (read: other classes) of vertebrate that birds pertained to. This has been disputed up to today, so that while we see them as stemming from within the reptile class, and the dinosaurs themselves (however a person wants to rank them, that's been disputed, too), we are finally catching up. Ancient concepts aside, I feel that they were wrong for several millennia, and it was not for any choice of a "they can't be members of Reptilia" but because of a poor concept of the term "reptile." This, too, has clarifed over the decades. Reptiles are hardly cold-blooded, sluggish animals. Even traditional ones. <We can have our cake and eat it too (at least in many cases), but only if strict cladists come to realize that there is a useful middle ground approach to classification, and that semi-paraphyletic groups (or call them semi-holophyletic if that makes them more palatable) often offer the best of both traditional eclecticism and traditional cladism at the same time.> How does one get to be semi-paraphyletic? You either are monophyletic (stem from a natural ancestor) ... or are not (been put there subjectively [for whatever reason, traditionally to refer to typology and superficial similarity]). Semi-monophyly or -holophyly or -paraphyly is like splitting concepts of descent. Yes, I can be presented in one ancestor's phylogeny, or another's, but I can be presented in both, not exclusively the one's. <I don't know what Jaime Headden meant when he mentionned a "prescription for paraphyletic groups", but this is the kind of compromise I have long prescribed (modified paraphyly that results in cladistic nesting).> I personally feel the prescription offered makes official recognition of paraphyletic taxa as a statement that they are natural groups that can be recognized, and its up to the reader's subjectivity to consider which group he'd rather acknowledge. My recommendation is that paraphyletic taxa be ignored, but that groups to reflect type can still be inferred from lay terminology, as in "anapsid" compared to "Anapsida". If Anapsida is considered paraphyletic, then the term anapsid can still be applied in an historical context, but not in reflection of its naturality by retaining the taxon name. Or, let me use PhyloCode's recommendation: _Anapsida_ can be explicitly defined in such a way that would clarify its life as a monophyletic taxon ... but the term anapsid will always remain as a junkyard novelty that one often wants go out and see, like one's grandpa's Model-T. My prescription is therefore: Do not recognized paraphyletic taxa, only groups in which typological information can be conveyed. If there are those who want a paraphyletic Reptilia because they don't want a descendant (which most recognize as occuring) like Aves to be included, for whatever typological or historical reason, they can explicitly make a phrase to refer to a Reptilia lacking Aves, not a taxon name. Perhaps the PhyloCode can reflect this in its articles? ===== Jaime A. Headden Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na Where the Wind Comes Sweeping Down the Pampas!!!! __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/