Phylogenetic analysis of Tubificidae (Annelida, Clitellata) based on 18S rDNA sequences

Tubificids are aquatic clitellate worms, but recent analyses of morphologic al characters suggested that this family, as currently recognized, is parap hyletic. Sequences of the 188 rDNA gene of 40 protostome worm species (incl uding 13 representatives of the Tubificidae) and 2 mollusc species were cla distically analyzed to test the monophyly of the Tubificidae and that of so me of its constituent subfamilies. Under all alignments tested, the same ge neral phylogenetic pattern emerged. The data support the idea that the Naid idae, another clitellate taxon, is associated with some "rhyacodriline" gro ups within the Tubificidae. The data also corroborate the idea that the Tub ificinae and the Limnodriloidinae are monophyletic but indicate that the Rh yacodrilinae and the Phallodrilinae are not, Bathydrilus does not appear to be closely related to other "phallodriline" genera. (C) 2000 Academic Pres s.