All:
Ed Cutler's comments on the Rouse & Fauchald "articulation" paper do, I
believe, convey the sort of reaction one would want to see to such an
analysis. Namely, to stimulate positive thinking about some very fundamental
issues. Whether Rouse & Fauchald were mistaken in some of their
interpretations or did not read every piece of literature for every taxon in
each phylum is of no relevance. I dare say my own interpretations of
characters as part of my research on sabellids changes with my mood. While I
take Cutler's comments to be constructive, it would have been more
illuminating had he incorporated this information into the Rouse & Fauchald
data set and discussed the results. Science is powered by our
interpretations of what we percieve around us, but Science only grows when
interpretations are synthesized into the more complete framework of
explanatory hypothesis formation.
The controversy over phylum relationships will not die down any time soon
for one very big reason: our understanding of relationships at most levels
within phyla are not much better than meagre. To (theoretically) have a more
complete understanding of, say, plesiomorphic states for the taxon
Polychaeta (assuming monophyly) would necessitate having patterns of
relationship among families (assuming monophyly), which would necessitate
patterns of relationship among genera (ditto), etc., etc. Such simply is not
the case. Phylogenetic research programs for invertebrates are pitifully
lacking. As such, I'm generally critical of those who attempt phylum-level
analyses; which seems to be the growing trend with the advent of the
misguided and grossly naive notion that molecular sequence data will tell us
how phyla are related. I do, however, applaud Rouse & Fauchald for their
efforts because their explicit intent is to work down to less general levels
for the purpose of then going back up. This is a classic case of reciprocal
illumination. Yet, rather than colleagues engaging in disputes about what
phylum is related to another based on piecemeal evidence, our collective
efforts really need to focus on expanding phylogenetic research within
polychaete families, and for the most part genera and species. It is truely
astounding how few polychaete families and genera can be considered
monophyletic - a fact which should be the most compelling reason not to
worry so much about phylum relationships.
Rather than focusing our efforts on showing how Rouse & Fauchald are wrong,
I do hope that invertebrate systematists will seek to improve the knowledge
base of within-phylum relationships such that analyses among phyla can go
beyond the anectdotal.
Regards,
Kirk Fitzhugh
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Kirk Fitzhugh
Associate Curator of Polychaetes
Research & Collections Branch
Los Angeles County Museum of Natural History
900 Exposition Blvd
Los Angeles CA 90007
Phone: (213) 744-3233
FAX: (213) 746-2999
e-mail: fitzhugh at bcf.usc.edu
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