Predictivity (was: NOT-inflated Family Staphylinidae)

Ken Kinman kinman2 at YAHOO.COM
Sat Feb 12 22:49:18 CST 2005


Hi Don (and others),
      Michael has obviously mixed apples and oranges (Vermes and Nematocera) in his examples.  He calls them both non-monophyletic, and we all know that Vermes is horribly polyphyletic and worthless.  On the other hand, Nematocera is paraphyletic, BUT it is an extremely useful taxon (even some strict cladists still use it).

      So is Nematocera predictive?  You betcha it is!!!  If you find a fly (possessing Dipteran synapomorphies) which lacks the synapomorphies of Brachycera (= Orthorrhappa and Cyclorrhapa), you can be almost certain it is a Nematoceran.  Or conversely, any new nematoceran you find will almost always have only the nematoceran plesiomorphies.  Neither holophyly or paraphyly is 100% predictive due to homoplasies (especially those pesky reversals).   The literature is full of references to Nematocera (a paraphyletic taxon), so refusing to put it into a classification (just because it is paraphyletic) would indicate an extremely obstinate and close-minded strict cladist is the culprit who wants to exclude this additional information just because their religion (Hennigian "rules") forbids it.

      I can fully understand Michael's displeasure with polyphyletic groups (everyone can), and even his displeasure with unannotated paraphyletic groups.  But when they are properly labelled as such, paraphyletic groups actually add more information to a classification.  And if strict cladists would look beyond their own particular branches of the Tree of Life, they would realize that we can't have a real Tree of Life without paraphyletic taxa.

     Here is the initial part of my classification of Diptera (the full classification was posted on Taxacom on 17 March 2004; see the Archives).  The first version has suborders inserted and the second version doesn't (same topology, just less information).  Both are cladistic in an informational sense, but the first is divided into three very useful suborders (and the first two of those---shown here---are both paraphyletic).  In a group like Coleoptera (which is cladistically very poorly known by comparison), paraphyly can be even more necessary and useful.  The old inexplicit paraphyly should definitely be discarded, but that does not mean this modern crusade to attack every single paraphyletic taxon is much better (and in some ways, it is even worse).

ORDER DIPTERA
  1  Nematocera% (primitive flies)
          1  Tanyderidae
          B  Ptychopteridae
          2  Thaumaleidae
          b  Simuliidae
          c  Ceratopogonidae
          d  Chironomidae
          B  Dixidae
          C  Corethrellidae
          D  Chaoboridae
          E  Culicidae
          3  Nymphomyiidae
          B  Deuterophlebiidae
          C  Blephariceridae
          4  Tipulidae (sensu lato)
          5  Psychodidae
          ?  Axymyiidae
          6  Perissommatidae
             Scatopsidae
             Canthyloscelidae
          7  Pachyneuridae
          B  Bibionidae
          C  Mycetophilidae
          D  Cecidomyiidae
          ?  Rangomaramidae
          E  Sciaridae
          8  Anisopodidae
          9  {{Brachycera}}
              (= Orthorrhapa + Cyclorrhapa)

 _1_ Orthorrhapa (primitive brachyceran flies)
          1  Pantophthalmidae
          B  Xylomyidae
          C  Stratiomyidae
          2  Vermileonidae
          3  Xylophagidae
          B  Ragionidae
          ......... and so on...

*************************************

  ORDER DIPTERA (paraphyly eliminated; yes, I know how to do that too) (but therefore less balance; and less information; AND also more potential instability, especially in other groups that are less well-known than this)

          1  Tanyderidae
          B  Ptychopteridae
          2  Thaumaleidae
          b  Simuliidae
          c  Ceratopogonidae
          d  Chironomidae
          B  Dixidae
          C  Corethrellidae
          D  Chaoboridae
          E  Culicidae
          3  Nymphomyiidae
          B  Deuterophlebiidae
          C  Blephariceridae
          4  Tipulidae (sensu lato)
          5  Psychodidae
          ?  Axymyiidae
          6  Perissommatidae
             Scatopsidae
             Canthyloscelidae
          7  Pachyneuridae
          B  Bibionidae
          C  Mycetophilidae (sensu lato)
          D  Cecidomyiidae
          ?  Rangomaramidae
          E  Sciaridae
          8  Anisopodidae
          9  Pantophthalmidae
          B  Xylomyidae
          C  Stratiomyidae
         10  Vermileonidae
         11  Xylophagidae
          B  Ragionidae
         ........and so on...




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