Leech Diversity in the Maghreb (North Africa): A Checklist and a Case Report of Parasitism on a Berber Toad (Sclerophys mauritanica) in Algeria

Leeches (Hirudinea) are ecologically important annelids that interact with a wide range of aquatic vertebrates, yet their diversity, distribution, and epidemiological relevance remain poorly documented in North Africa. Here, we provide a comprehensive synthesis of freshwater and marine leech species reported from the Maghreb (Algeria, Tunisia, and Morocco), based on an extensive review of the available literature. In total, 21 species belonging to 13 genera and four families (Glossiphoniidae, Erpobdellidae, Hirudinidae, and Piscicolidae) are documented, with updated information on their ecology, host associations, and geographic distribution. In addition to this regional checklist, we report the first confirmed case of Batracobdella algira heavy parasitism on the Berber toad (Sclerophrys mauritanica) in Algeria. A single adult toad was found heavily infested by multiple leeches (n = 17), some of which bore spermatophores attached near the reproductive opercula, suggesting possible in situ mating behavior on the host. The high infestation observed in this single specimen may constitute an outlier, requiring further sampling to assess the effect of leeches on the anuran population in the region. By integrating faunistic data with a novel field observation, this study highlights the overlooked leech biodiversity in the Maghreb and suggests their possible ecological and epidemiological significance. Our findings emphasize the need for further investigations into leech–host interactions, pathogen carriage, and their implications for amphibian conservation and One Health in North Africa.