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

ABSTRACT

Historically, 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.

KEYWORDS:

• Hirudinea
• DNA barcoding
• COI variation
• species delimitation
• leech
• North America
• Europe

Acknowledgements

We are very grateful to Danielle de Carle for guidance in DNA extraction and amplification, and Claire Manglicmot and Kristen Choffe for assistance in DNA sequencing. Peter Trontelj provided generous aid with collection efforts in Slovenia, and Alejandro Oceguera-Figueroa, Danielle de Carle, Rafael Iwama, Claire Manglicmot, Madeleine Foote and Kevin Anderson were all instrumental in gathering North American specimens. We thank Michael Tessler for the script used to run TNT. Two anonymous reviewers and the Editor provided helpful comments that greatly improved a previous version of this manuscript. SK was funded by a ROM Peer Review Grant, an NSERC Discovery Grant and an Olle Engkvist Byggmästare Foundation grant.

Data availability statement

The data that support the findings of this study are openly available in GenBank at https://www.ncbi.nlm.nih.gov/, under accession numbers MK479230–MK479280. All specimen vouchers are deposited in the Invertebrate Zoology collection at the Royal Ontario Museum; catalogue numbers are referenced in Table 1.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Stiftelsen Olle Engkvist Byggmästare; and the Natural Sciences and Engineering Research Council of Canada.