Application of 16S, 18S rDNA and COI sequences in the molecular systematics of the earthworm family Lumbricidae (Annelida, Oligochaeta)

An overview of the results of our attempts in using the tools of molecular taxonomy of lumbricid earthworms, namely partitioned and combined 16S, 18S rDNA and COI sequences is presented. Clear and consistent conclusions were formulated regarding the validity of the genera Octodrilus, Octolasion and Dendrobaena, where the patterns of the cladograms fit the species groupings by means of morphological and anatomical characters. It is also true for the species attributed to the genus Aporrectodea indicating that the separation of Aporrectodea from Allolobophora might be phylogenetically correct. Of the three investigated genes, only the 16S rDNA gene produced reliable results when analyzed separately. These partitioned trees show the same topology as the combined trees, only the bootstrap supports being somewhat different. It is especially prominent in case of some problematic clades such as Aporrectodea and Eisenia. Methodical improvements and new gene approaches are required because there are species (especially ubiquitous or peregrine ones) which cannot be properly analyzed by actual techniques.