American Society of Hirudotherapy

Genetic variation, pseudocryptic diversity, and phylogeny of Erpobdella (Annelida: Hirudinida: Erpobdelliformes), with emphasis on Canadian species

Phylogenetic study published in Molecular Phylogenetics and Evolution (2019)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Genomics & ProteomicsAnderson K et al. · Molecular Phylogenetics and Evolution, 2019

Abstract

Leeches of the family Erpobdellidae are important members of benthic freshwater environments, where they are voracious predators of other invertebrates and an important source of nutrition for several species of vertebrates. Beset by a lack of reliable diagnostic morphological characters and destructive identification processes, molecular approaches have, in recent years, been employed to illuminate the relationships within this family, and DNA barcoding has been employed for identification purposes. However, an understanding of the levels of genetic variation across the geographic distributions of members of the genus is still lacking. Herein, we sequence the mitochondrial COI locus for 249 newly collected North American individuals, representing 5 species, as well as mitochondrial 12S rDNA, nuclear 18S rDNA, and nuclear 28S rDNA for a select subset of these. Our COI dataset was leveraged to detect potential cryptic species, and to calculate genetic distances as a proxy for the degree of gene flow between populations. Augmented by numerous sequences from GenBank, the multilocus dataset was used to reconstruct a phylogenetic hypothesis for worldwide members of the genus. Beyond corroborating previous overarching phylogenetic frameworks, our results show that an undescribed species that is morphologically and genetically similar to Erpobdella punctata exists in sympatry with this species - the new species has likely been overlooked in previous studies due to its morphological similarity with Erpobdella punctata. Erpobdella bucera is reported from Canada for the first time; and Erpobdella microstoma is newly reported from Saskatchewan and placed in a phylogeny for the first time. Finally, we find evidence for genetic structure in both E. cf. punctata and Erpobdella obscura that is correlated with major river drainage basin boundaries in North America.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal ArticleResearch Support, Non-U.S. Gov't
Indexed MeSH termsAnimalsAnnelidaBiodiversityCanadaElectron Transport Complex IVGenetic VariationHaplotypesMitochondriaPhylogenyRNA, Ribosomal

Summary

249 newly collected Erpobdella leech specimens from North America with multilocus phylogeny revealed cryptic sympatric species, range expansion of Erpobdella bucera into Canada, and structured populations correlated with major river basin boundaries.

Why This Matters for Hirudotherapy

This molecular-systematics study (Anderson et al., Molecular Phylogenetics and Evolution, 2019) sequenced the mitochondrial COI barcode for 249 newly collected North American Erpobdella leeches (representing 5 species), plus 12S rDNA, nuclear 18S and 28S for a subset, and reconstructed a worldwide phylogeny of the genus. It uncovered an undescribed pseudocryptic species living in sympatry with and easily confused for Erpobdella punctata, reported Erpobdella bucera from Canada for the first time, newly reported Erpobdella microstoma from Saskatchewan, and found genetic structure in E. cf. punctata and E. obscura correlated with major river-drainage basins. For hirudotherapy the value is foundational and taxonomic rather than clinical: accurate species identification underpins the field, and this work shows that morphology alone can mask distinct leech species, reinforcing why DNA barcoding matters for correctly identifying and distinguishing leeches in research and sourcing. The honest caveat is that Erpobdella are predatory freshwater leeches, not the blood-feeding medicinal Hirudo species used in therapy, so this paper carries no treatment or efficacy implications; it is relevant to leech biology and identification methodology only.

Citation

Genetic variation, pseudocryptic diversity, and phylogeny of Erpobdella (Annelida: Hirudinida: Erpobdelliformes), with emphasis on Canadian species.

Anderson K et al. · Molecular Phylogenetics and Evolution, 2019

Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026

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