Fauchald.Kristian at nmnh.si.edu
Thu Oct 28 16:20:33 EST 1999
The Echiura is such a nice compact group so I do not believe they
would ever become scattered all over the Annelida. Thus, if the group is
monophyletic, it is going to stay together no matter what; if it consists of
two recognizable subunits, fine, if it does not, equally fine.
It is actually trivial whether the group is considered a phylum or a
family: Ranks such as these are artificial and represent a major problem if
one starts to take them seriously. The important point is that the group is
clearly monophyletic: There is a branch in any cladogram including these
taxa that can be named Echiura, with all sorts of synapomorphies tied to it.
I have no clear idea of what its sister-taxon would be. I hope that will
become clear as we study them, and the rest of the annelids.
I believe it is important that we understand the artificial nature of the
ranks: Taking them seriously leads to attempts at comparing them across
the animal kingdom, and to all sorts of absurdities, such as naming certain
features as family-level characters, genus-level characters etc.
The three gentlemen are eminent scholars on their groups, and I
believe they should be happy the groups they study are so obviously
monophyletic: For us working in a far messier world, this is one of the first
goals to reach.
<Fauchald.Kristian at NMNH.SI.EDU>
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