[Taxacom] Elimination of paraphyly: sensible or not?
kinman at hotmail.com
Thu Feb 8 20:59:35 CST 2018
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:
* †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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