Hello Annelida,
I noticed a couple of papers of probable interest in the latest Molecular
Phylogenetics and Evolution. Cites with abstracts below.
http://www.academicpress.com/mpe
Erséus, C., T. Prestegaard, & M. Källersjö. 2000. Phylogenetic Analysis of
Tubificidae (Annelida, Clitellata) Based on 18S rDNA Sequences. -- Molecular
Phylogenetics and Evolution 15(3):381-389.
"Tubificids are aquatic clitellate worms, but recent analyses of
morphological characters suggested that this family, as currently
recognized, is paraphyletic. Sequences of the 18S rDNA gene of 40
protostome worm species (including 13 representatives of the Tubificidae)
and 2 mollusc species were cladistically analyzed to test the monophyly of
the Tubificidae and that of some of its constituent subfamilies. Under all
alignments tested, the same general phylogenetic pattern emerged. The
data support the idea that the Naididae, another clitellate taxon, is
associated with some "rhyacodriline" groups within the Tubificidae. The
data also corroborate the idea that the Tubificinae and the Limnodriloidinae
are monophyletic but indicate that the Rhyacodrilinae and the Phallodrilinae
are not. Bathydrilus does not appear to be closely related to other
"phallodriline" genera.
Martin, P., I. Kaygorodova, D. Y. Sherbakov, & E. Verheyen. 2000.
Rapidly evolving lineages impede the resolution of phylogenetic
relationships among Clitellata (Annelida). -- Molecular Phylogenetics and
Evolution 15(3):355-368.
"The phylogenetic relationships of the Clitellata were investigated using a
data set with published and new complete or partial 18S rRNA and mtCOI
gene sequences of 13 and 49 taxa representing 8 and 14 families,
respectively. Three different alignments were considered for 18S, and the
possible influence of departures from rate constancy among sites was
evaluated by analyses using a model of rate heterogeneity. Maximum-
likelihood estimates of the shape parameter of the distribution were very
low, whatever the alignment or the gene considered, suggesting that
phylogenetic reconstructions taking into account the rate heterogeneity
among sites are likely to be the most reliable. Analyzed separately, the two
genes did not resolve the relationships among the Clitellata, but the
consensus tree was congruent with the morphology-based relationships.
Our data suggest the inclusion of the Euhirudinea, Acanthobdellida, and
Branchiobdellida in the Oligochaeta and suggest the Lumbriculidae as the
link between both assemblages. Although separate analyses of both genes,
as well as different alignments for the 18S rRNA sequences, yielded
conflicting results concerning the phylogenetic position of leeches and
leech-like worms vis-à-vis the Oligochaeta, subsequent analyses using the
model greatly reduced the observed inconsistencies. Our analyses show
that among the Clitellata, the leeches and the leech-like and gutless worms
represent significantly faster evolving lineages. It is suggested that the
observed higher mutation rates may be explained by the fact that these
lineages contain almost exclusively commensal and/or parasitic taxa.
--
Geoff Read <g.read at niwa.cri.nz>
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