Predictivity & Tetrapoda nightmare

Ken Kinman kinman2 at YAHOO.COM
Sun Feb 13 11:51:17 CST 2005

Okay Curtis,
      You want to bring up the herpetological mess again, fine.  Predict for me whether the Tree of Life classifies Acanthostega, Ichthyostega, Seymouria, temnospondyls, etc. as Tetrapoda.  Hell no!  Call them "amphibians", or even "tetrapods", and some strict cladist will probably jump down your throat (and Michael wonders why he is always causing eyes to glaze over).  EVERYBODY, please just look at this Tree of Life page for Stegocephalia (Terrestrial Vertebrates), and you will see where most classifications are headed under strict cladism:

     And their classification of Reptilia is almost as bad (and getting worse as time passes).  And being a taxon loaded with homoplasies, predictivity is going to be extremely limited no matter how you approach the reptiles.  Turtles are likely to be Diapsida that have lost the diapsid condition (predictivity has been almost worthless trying to place them).  Strict cladism has worked pretty well for Hennig's Diptera, but when applied to herpetology (and many other disciplines) it turned into a disaster.   The old four Class system for tetrapods works just fine unless you have a strict cladist attacking you (with or without a book of legalistic phylocode definitions).  Like talking to a bunch of tax lawyers, and they have only just begun to complicate matters (and fighting amongst themselves over the details).  ANYWAY, I am sticking with an accurate (but simple) classification of tetrapods that everyone can related to (and keep in their head), and we cladists can put all those messy cladistic details within a paraphyletic Amphibia and Reptilia (it's just as useful today as it was when I was growing up in the 1950's):

Tetrapoda (four main types)
   Amphibia% (paraphyletic to Amniota)
   Reptilia%% (doubly paraphyletic)

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