Paraphyly

Joseph E. Laferriere joseph at IRIS.CEAMISH.UAEM.MX
Fri Jun 13 07:58:29 CDT 1997


> many people consider birds a paraphyletic group to dinosaurs, but there are
> still significant problems with the evidence and so there are many others who
> do not accept the above declaration.

Sorry to seem picky, but I have never seen anyone claim Aves is
paraphyletic. All birds are descended from a common ancestor,
Archaeopteryx or something fairly close to it. Its origin from the
dinosaurs makes the traditional class Reptilia paraphyletic, not Aves.

> OK, If I go out in the field and discover two Mus species, which one should
> be called M. oldus and which is M. newus?

Whichever one contains the type is Mus oldus, the other Mus newus (or, to
be less Americocentric about this, Mus antiquus and Mus novus). This may
not seem logical, but it is the way the system has been set up.
Nomenclature is a field interconnected with but distinct from taxonomy,
and one must distinguish between the two.

Someone mentioned Cronquist's essay arguing in favor of accepting
paraphyletic taxa. He (and Tom Lammers) make some very valid points, with
which I agree. However, where Cronquist and I part company is when he
argued in favor of accepting POLYphyletic taxa. In my opinion, that
should never be done at any level.




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