A phylogenetic analysis of the Lumbriculidae (Annelida, Oligochaeta)

Abstract

Though the Lumbriculidae is a monotypic taxon including Kurenkovia, there is no support from cladistic analyses for the Kurenkovidae. The unusual nature of the vasa deferentia, which run between the epithelial and muscular layers of the body wall as in some Haplotaxidae and Glossoscolecidae, may affect that decision. The Dorydrilidae is a sister-group to the Lumbriculidae. Lamprodrilus and the Lake Baikal endemic genera are now seen as advanced forms which may have given rise to some Asian and Pacific rim North American taxa. Several of the genera best represented in Europe have the plesiomorphic pattern of the reproductive system, with gonads in GI–GIII but atria limited to GII, so that two pairs of vasa deferentia are associated with them. This pattern is shared with the Branchiobdellida, and whereas median fusion of the atria has happened independently in the two taxa, these two taxa may arise from a common ancestor despite the degree of specialization to an epizooic habit in the branchiobdellidans. Most subgeneric taxa entered into the analyses are grouped at least close to their congeners, with the exception of Neoscolex, which may be more closely related to the pair of Kincaidiana species than to Styloscolex. Rhynchelmis may have an origin distinct from that of Lamprodrilus, Kincaidiana, and Neoscolex, as the loss of the anterior testes may be convergent and not monophyletic as suggested here.