Digeneans from deep-sea marine teleosts off the Outer Hebrides, Scotland, including the description of Brachyenteron helicoleni sp. nov. (Zoogonidae)

Fifteen species of digeneans are reported from the waters off the islands of the Outer Hebrides, off north-western Scotland. Trifoliovarium allocytti comb. nov. from Neocyttus helgae is described, figured, and reported for the first time in the northern hemisphere. Brachyenteron helicoleni sp. nov. from Helicolenus dactylopterus is described and considered distinct from other species in the genital pore being at the level of the pharynx, the relatively narrow caeca, the vitellarium being mainly at the level of the ventral sucker and the anterior hindbody, the posteriorly situated, oblique testes, the small amount of post-testicular uterus, the small, delicate cirrus-sac and the large eggs. Derogenes varicus and Lepidapedon arlenae are reported from Caelorhinchus labiatus and Paralepidapedon williamsi is reported from Cottunculus thomsoni for the first time. Steringovermes notacanthi and Prodistomum priedei are reported from off Scotland for the first time. The reports of Derogenes varicus at 1,800 m depth and Zoogonoides viviparus at 1,000 m are deeper records than have previously been published.