Greek, acantha = spike, bdella = leech; Latin, peledinus = dark.
Species of blood-sucking leeches of the family Acanthobdellidae, which parasitizes on fish (e.g., salmonids) in freshwater. The individuals of this species reach a length of up to 3.5 cm and are (as the other members of this group) characterized by hooks at the four bristles of the first five segments. This makes them looking like the systematically related polychaetes within the common phylum Annelida. These hooks apparently have similar functions as the anterior sucker, which, however, lacks in this species. While practically all other leeches are subdivided inside in 32 segments, A. pelledina is an exception, since this species possesses only 29 inner segments. However, when seen from the outside, much more ringlike structure becomes visible, since about 2–14 outer rings correspond – depending on the species – to a single inner segment. In the case of A. peledina, however, each segment has strictly 4 bristles.