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Re: Defending grades (Was: Re: Archaeopteryx (rant))



Aspidel wrote-


> > Similarly, Reptilia is defined as
> > the ancestor of extant reptiles (crocodilians, squamates, Sphenodon,
> > testudines) and all its descendents.  Thus excluding mammals.
>
> So, where do pelycosaurs fit?

"Pelycosaurs" are a paraphyletic grade of non-therapsid synapsids.  Not
reptiles.  Very simplified-
|--Amphibia
`--+--Synapsida
   |  `--+==pelycosaurs
   |     `--Mammalia
   `--Reptilia
      `--+?-Testudines
         `--+--+--Squamata
            |  `--Sphenodon
            `--+--Crocodilia
               `--Aves

Mickey Mortimer