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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 6526

Seung Y. Moon, Chang B. Kim, Stuart R. Gelder, and Won Kim; Phylogenetic positions of the aberrant branchiobdellidans and aphanoneurans within the Annelida as derived from 18S ribosomal RNA gene sequences. Hydrobiologia 324(3):229-236, 1996

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Different hypotheses have been proposed on the phylogenetic relationships of branchiobdellidans and aphanoneurans among the Annelida based on the anatomical and embryologial characters. The 18S ribosomal RNA gene sequences have been analyzed from representatives of the three major taxa of the Annelida plus the branchiobdellidans and aphanoneurans to assess their phylogenetic relationships to each other. In this preliminary study, all of the phylogenetic analyses show the branchiobdellidans as a sister group to the leeches, rather than the oligochaetes. The position of the aphanoneurans is stable as an independent taxon that evolved after the polychaetes branched from the evolutionary stem, but before the ancestral oligochaetes emerged.