[Taxacom] Dearthropodization

Kenneth Kinman kennethkinman at webtv.net
Thu Mar 5 22:23:33 CST 2009

Dear All,
       While I am on this line of thinking, it is very pertinent to my
views on arthropod phylogeny (and various other metazoan phyla).  A
variety of characters of arthropodization are often seen as important to
the phylogeny of Panarthropoda.  UNFORTUNATELY, I am convinced that
there has been a failure to also recognize the importance of
de-arthropodization.  Are nematodes actually de-arthropodized
descendants of something like tardigrades?  And even more importantly,
could the whole "Annelid" mess be a combination of plesiomorphic (and
paraphyletic) polychaetes being lumped in with the far more derived, but
de-arthropodized, forms we call "clitellates"?                        
        Until such questions are answered, their interrelationships (and
those of many other metazoan phyla) will remain problematic.  Is
Ecdysozoa really a clade or not?  Poor choice of characters (and
outgroup selection) have probably led phylogenetics to many false
conclusions in this area.  The failure to pursue de-arthropodization as
a major source of metazoan diversity is perhaps still the greatest
hurdle to understanding their evolution on a broad scale.
         ---------Ken Kinman  

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