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



Daniel Grossberg wrote-


> While ancestral reptiles are also ancestral to aves, we should maintain
this
> distinction.  Why?  Because by placing them in the clade of reptiles, we
would
> have to do the same for mammals, and place reptiles under amphibians, etc.
It
> would go ad infinitum.

Not true.  Amphibia is defined as extant lissamphibians (salientians,
caudates, gymnophionans) and all taxa more closely related to them than
amniotes.  Thus, it excludes reptiles.  Similarly, Reptilia is defined as
the ancestor of extant reptiles (crocodilians, squamates, Sphenodon,
testudines) and all its descendents.  Thus excluding mammals.

Mickey Mortimer