Using 18S rDNA, mitochondrial cytochrome c oxidase subunit I and morphological characters, the Branchiobdellidae (Annelida, Clitellata) were shown to form a monophyletic group distinct from the leeches using two distant ‘oligochaetes’ as outgroups. The study used 20 branchiobdellid species from 14 genera in four subfamilies with these representing each of the taxon’s three distributional regions in the Holarctic realm. No mono...

The spermatozoa of six species belonging to the branchiobdellidan family Branchiobdellidae (i.e. Xironogiton victoriensis , Cirrodrilus kawamurai , Ankyrodrilus legaeus , Xironodrilus formosus , Branchiobdella kobayashii , Branchiobdella orientalis ) were studied and compared to the other sperma‐tozoa already described in the group. A parsimony analysis was performed on the spermatozoal data of the species examined, as well as...