I have been following the Echiura debate with some interest and I just
wanted to add some comments. I think that a comparison of the Echiura to
the pogonophorans makes Kristian's point all the more relevant. Taxonomic
ranks are purely man made and have no meaning in nature. Meredith
Jones (and Ivanov to some degree) was the one who was pushing for the
"phylum" status of both perviate pogonophorans and vestimentiferans
based on (what I consider) minor body plan differences. Several genes (I
am drawing both on published and unpublished data) show very little
diversity with the vestimentifera and limited diversity in the perviates. A
rankless taxonomic scheme based on monophyletic groups would avoid
these problems - diversity and differences of opinion on importance of
certain features...as well as the abundance of names for the same
monophyletic clade as is the case with pogonophorans.
In the 1998 paper quoted by Geoff Read (Cah. Biol. Mar. 39:355-358 ),
we did agree with McHugh's use of the term Siboglinidae (p357).
Ken Halanych
Biology Dept. MS 33
Woods Hole Oceanographic Institution
Woods Hole, MA 02543
<halanych at metazoan.whoi.edu>
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