Clades, cladons, and "cladifications"

Ken Kinman kinman2 at YAHOO.COM
Mon Jun 14 22:12:36 CDT 2004

Curtis Clark wrote:
     Ironically, had the names represented clades and the codes grades, I would probably be wildly supportive of it.
    Well, you are not the first to make that observation.  But what I find rather ironic is that such objections fail to acknowledge that paraphyly is optional in the Kinman System, and quite a few groups are classified completely cladistically (with no paraphyletic groups at all).  Of the 1,719 Orders, I would estimate 95-99% are regarded as clades (i.e. holophyletic).  The percentage is smaller than that at Class and Phylum level, but not surprising given our lack of knowledge at those levels.

    My goal was too minimize paraphyly in a way that balanced the two approaches and maintained stability as much as possible.  Actually I bent over backwards in some cases, such as classifying Bivalvia as a clade (even though I strongly suspect it is a paraphyletic "grade" of basal molluscs).  As for plants, I still classify Bryophyta as paraphyletic with respect to the tracheophytes, Pteridophyta paraphyletic with respect to the spermatophytes, and Pinophyta paraphyletic with respect to the Magnoliophyta (especially the latter where angiosperm origins are still an abominable mystery).  These phylum (division) level taxa are as useful as ever and will be for a long time to come.

    Usefulness and stability alone are sufficient arguments for the continued limited use of paraphyly (not to mention the fundamental paraphyletic origins of most of the species which gave rise to higher taxa).  Without extinction and a poor fossil record, we would have to recognize a much larger percentage of paraphyletic taxa.  Strict cladists should thank their lucky stars for that, or they would be neck-deep in trouble already.  The holophyly (strict monophyly) of many taxa is an illusion based on a lack of information (extinction and poor fossil preservation).  I have little sympathy with the protestations of strict cladists (even the more moderate ones which find PhyloCode distasteful).  Rejection of ALL paraphyly is a learned response that I can certainly understand, but it can be deprogrammed in those willing to make the effort.  Thankfully, Botany has been more resistant to such paraphylophobia, whereas fossil vertebrates are near the epicenter of the phenomenon (especially the dinosaurs, although there are noteable exceptions even in that discipline).  Needless to say, my two or three years on the Dinosaur Mailing List were quite stressful and coincided with some of my more argumentative debates in this forum.  These days I am relatively mellow except when it comes to across-the-board attacks on paraphyly (which I find illogical and harmful).
         ------ Cheers,
                        Ken Kinman

More information about the Taxacom mailing list