American Society of Hirudotherapy

Phylogenetic relationships and species delimitation in Haemopis

Phylogenetics study published in Molecular Phylogenetics and Evolution (2022)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Genomics & ProteomicsKvist S et al. · Molecular phylogenetics and evolution, 2022

Abstract

The Holarctic leech genus Haemopis currently includes 11 species, all of which are macrophagous, as opposed to their more infamous bloodfeeding counterparts among hirudiniform leeches. In spite of their ecological importance as fish food and predators of freshwater invertebrates, there is a paucity of data regarding morphology and genetic variation that might guide future identification efforts for members of the genus. The lack of detailed descriptions of distinguishing morphological features, coupled with the absence of a robust phylogenetic hypothesis for the genus, have conspired to prevent meaningful inferences on the natural history of the group. In an attempt to remedy this, we present new genetic (using COI, 12S rDNA, 28S rDNA and 18S rDNA) data for the majority of the known species diversity within the genus in order to both infer a phylogenetic hypothesis and to introduce authoritative DNA barcodes for the newly collected species. The potential of these barcodes is increased through rigorous morphological investigations of the specimens, with comparisons to the original literature. Our resulting phylogenetic hypothesis is agnostic as to the geographic origin of the genus, with equal probability afforded to both a Nearctic and Palearctic origin. Beyond this, we show that there is a strong tendency towards a barcoding gap within the genus, but that a distinct gap is lacking due to the relatively high genetic variation found within H. marmorata. Taken together, our results shed light on species delimitation within, and evolutionary history of, this often-neglected group of leeches.

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 termsAnimalsLeechesPhylogenyAnnelidaDNA, RibosomalFresh Water

Summary

Multilocus phylogeny resolves species relationships within Haemopis (horse leech genus); recognizes new species and refines biogeographic patterns.

Why This Matters for Hirudotherapy

This study examined phylogenetic relationships and species delimitation within the leech genus Haemopis, a group of macrophagous (non-bloodfeeding) freshwater leeches, using COI, 12S, 28S, and 18S rDNA sequences for the majority of known species. The authors generated a phylogenetic hypothesis and authoritative DNA barcodes, finding equal probability for Nearctic or Palearctic geographic origin, a strong tendency toward a barcoding gap (complicated by high variation in H. marmorata), and providing new morphological comparisons. For ASH, this is primarily taxonomic work on a non-bloodfeeding leech genus, so it has no direct bearing on hirudotherapy, anticoagulants, or leech-derived therapeutics. Its value is limited to contributing to broader leech systematics, which is one step removed from ASH's therapeutic focus.

Citation

Phylogenetic relationships and species delimitation in Haemopis.

Kvist S et al. · Molecular phylogenetics and evolution, 2022

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

This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.