[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: T-J Extinction event article (more media errors?)



> << This is an example how the use of paraphyletic taxa can mislead. "Both"
> have
>  living descendants, so they aren't extinct, even though no actual members
of
>  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
or
> 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.