[Taxacom] Elimination of paraphyly: sensible or not?

Kenneth Kinman kinman at hotmail.com
Thu Feb 8 20:59:35 CST 2018

Hi all,
        One example I gave of the unfortunate attempt to eliminate paraphyly is Class Sarcopterygii (with respect to the clade containing the four Classes of Tetrapoda).   The Wikipedia article ( https://en.wikipedia.org/wiki/Sarcopterygii ) has a beautiful tree in the Phylogeny section, but then in the Classification section comes up with this attempt to avoid paraphyly:

Subclass Sarcopterygii

  *   †Order Onychodontida<https://en.wikipedia.org/wiki/Onychodontida>
  *   Order Actinistia<https://en.wikipedia.org/wiki/Actinistia>
  *   Infraclass Dipnomorpha<https://en.wikipedia.org/wiki/Dipnomorpha>
     *   †Order Porolepiformes<https://en.wikipedia.org/wiki/Porolepiformes>
     *   Subclass Dipnoi<https://en.wikipedia.org/wiki/Dipnoi>
        *   Order Ceratodontiformes<https://en.wikipedia.org/wiki/Ceratodontiformes>
        *   Order Lepidosireniformes<https://en.wikipedia.org/wiki/Lepidosireniformes>
  *   Infraclass Tetrapodomorpha<https://en.wikipedia.org/wiki/Tetrapodomorpha>
     *   †Order Rhizodontida<https://en.wikipedia.org/wiki/Rhizodontida>
     *   Superorder Osteolepidida<https://en.wikipedia.org/wiki/Osteolepidida>
        *   †Order Osteolepiformes<https://en.wikipedia.org/wiki/Osteolepis>
           *   †Family Tristichopteridae<https://en.wikipedia.org/wiki/Tristichopteridae>
        *   †Order Panderichthyida<https://en.wikipedia.org/wiki/Panderichthys>
        *   Superclass Tetrapoda<https://en.wikipedia.org/wiki/Tetrapoda>

     And then there is the even more unfortunate Wikipedia article "Cladistic Classification of Class Sarcopterygii" ( https://en.wikipedia.org/wiki/Cladistic_Classification_of_Class_Sarcopterygii ) which is even worse because it doesn't include fossil taxa.  Aves is a "Subcohort", and Mammalia is a Parvclass.

      As Ernst Mayr would say, these are cladifications, not classifications.  And all it takes is one new fossil discovery to cause these cladifications to drastically change, while a classification with a paraphyletic Class Sarcopterygii would remain relatively stable.


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