Improved geographic sampling provides further evidence for the separation of Glossiphonia complanata and Glossiphonia elegans (Annelida: Clitellata: Glossiphoniidae)

Abstract

ABSTRACTHistorically, there has been much confusion surrounding the identity and separation of European and North American species of Glossiphonia (Annelida: Clitellata: Glossiphoniidae). Using cytochrome c oxidase subunit I (COI) sequences from newly collected specimens of Glossiphonia complanata and Glossiphonia elegans from a broad geographic range covering southern Canada, parts of the US, Slovenia and Croatia, we confirm that G. complanata is likely confined to Europe. The species is phylogenetically distinct from G. elegans, which seems to exclusively inhabit North America. Parsimony and maximum likelihood of the COI locus show the European samples placing as the sister group to an unidentified species of Glossiphonia from Russia, while the North American samples are the sister group to all other Glossiphonia species. We also investigate the consistency of number of crop cecae for separating these species and contrary to previous reports, this character shows no differences between our specimens of the two species. Additionally, the trees show evidence of subdivisions within both G. complanata and G. elegans, with some sequences separated by high ‘intraspecific’ distances. Forces might be shaping population structure and/or potential incipient speciation within these species, emphasizing the need for future research into the biogeography and population genetics of Glossiphonia.