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Re: Livezey and Zusi's big bird morph analysis [...]
True, but it advises caution for an apomorphy-based
definition of ratites.
Well, no such definition has ever been proposed, AFAIK...
given the sheer amount of homoplasies
Most of them are probably 1) correlated and 2) paedomorphic (which means the
correct coding for them is "?" in the paedomorphic taxa).
and the lack of good stem taxa.
Agreed. Finding them is all we can do against long-branch attraction.
Ratites are a good example where at present, a
node-based definition is superior to an
apomorphy-based one, even though node-based
definitions always run danger of excluding the next
lowest branch because nodes are both rarely known and
usually not identifiable as such, making them de facto
entities with hypothetical properties.
Then what about a branch-based definition? :-)
(It wouldn't get away from the "hypothetical properties", but an
apomorphy-based definition would make just one of those properties known.)
Raphidae is probably not acceptable
Unless you can live with having Raphidae inside Columbidae, that is. It is,
after all, monophyletic.
no matter whether the
Metaves are a homoplastic assemblage by and large
(which I find easier to believe at present given that
they fail to turn up elsewhere)
They have turned up in two different molecular analyses, and those are the
most recent ones... I'm optimistic about them.
erecting paraphyletic taxa (!!!),
As above - something there is no reason to anymore
I suppose they wanted to limit the number of ranks they had to use --
overlooking the fact that, instead of trying in vain to solve it, they could
have eliminated the "problem".