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Re: T-J Extinction event article (more media errors?)
> << This is an example how the use of paraphyletic taxa can mislead. "Both"
> living descendants, so they aren't extinct, even though no actual members
> the actual paraphyletic groups survive. >>
> This is not misleading; but it may be confusing because the paraphyletic
> groups under discussion have not been adequately defined. Define a
> paraphyletic group as the difference between an inclusive clade and one
> more of its included clades and there's no confusion.
Well, a paraphyletic group is still not extinct when a descendant survives.
For species, J. David Archibald has termed this "pseudoextinction" in his
1996 book about the K-T extinction (hey, we've arrived at the K-T from the
Tr-J!). If one counts the taxa that went extinct at a particular time, it is
nonsense to include pseudoextinct ones.