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Date: Tue, 06 Feb 2001 15:19:23 -0500
From: david baum <dbaum@oeb.harvard.edu>
To: PhyloCode@ouvaxa.cats.ohiou.edu
Subject: Re: apomorphy-based names
Kevin de Queiroz said: >When one examines the way in which certain names are used, it becomes very >clear that some people have an apomorphy-based concept of the clade to >which they are referring. It is true that we sometime conceptualize clades based on apomorphies. For example, like most botanists I think of Angiospermae as being "defined" by the enclosure of ovules/seeds in carpels. (Perhaps this reflects some kind of essentialistic core in us all that drives us to insert evidence [characters] as proxies for things [clades] whose existence we cannot directly observe.) However, I think that when we get to the point of naming a clade within the framework of the PhyloCode (or converting a preexisting name) we should be required to go beyond a "primitive," character-based understanding and say something about historical relationships. Thus, I think the name, "Angiospermae" should be attached to a specific genealogically specified clade: E.g.,"The most inclusive clade including Arabidopsis thaliana but not Gingko biloba, Pinus sylvestris, Welwitschia mirabilis......" or " the least inclusive clade including Amborella trichopoda, Nyphaea, etc......). Similarly, just because hair, mammary glands, a dentary-squamosal joint or whatever (!) have been taken to "define" (I prefer "diagnose") a clade named Mammalia does not, in my mind, negate the responsibility to attach the name to one unambiguously indicated clade. And the least ambiguous way to attach names to clade is using specifiers (and even then we are assuming a strictly divergent tree [but that's another topic!]). Jonathan Wagner said: >Without wishing to seem insulted, I feel I shold interject. I understand the frustration that Dr. Baum seems to feel regarding the differing approaches to nomenclature necessitated by our respective disciplines (see Dr. De Quieroz's points). I certainly don't want to imply that I think Dr. Baum is being deliberately coarse, sometimes I too feel his frustration too. However, I feel I must defend the practitioners of PT in vertbrate paleontology. I admit it was coarse and unfair to stereotype VP's in this way! As you note some frustration slipped-out. Negative comments about over-philosophical botanists are warranted in response! Jonathan also said: >VP workers may be more inclined toward apomoprhy-baed definitions, I do >not feel that we project a *need* for them. In that case where is this projection coming from? Maybe we are all disinclined towards apomorphy-based definitions but are politely assuming that somebody else wants them. So, who does? Based on the recent emails is this a fair summary? Pro: Kevin Anti: David H, David B. Open to allowing them but not inclined to use them: Jonathan, David M.(?) David David Baum Dept. Organismic and Evolutionary Biology Harvard University Herbaria 22 Divinity Avenue Cambridge MA 02138 Tel: (617)496-6744, -8766 Fax: (617)495-9484 dbaum@oeb.harvard.edu http://www.herbaria.harvard.edu/~dbaum