Affinities between Cutifilaria (Nematoda: Filarioidea), parasites of deer, and Mansonella as seen in a new onchocercid, M. (C.) perforata n. sp., from Japan.

A new dermal filarioid nematode, collected from Cervus nippon nippon (sika deer) on Kyushu Island, Japan, showed close affinities between the genera Cutifilaria and Mansonella (Onchocercidae: Onchocercinae): no buccal capsule, esophagus reduced to a thin fibrous tube, and female tail with four lappets. We propose Cutifilaria as a subgenus of Mansonella. Cutifilaria was distinguished from the five other subgenera, Mansonella, Tetrapetalonema, Esslingeria, Sandnema, and Tupainema, in having an area rugosa composed of transverse bands with tiny points, 14-16 papillae around the cloacal aperture, two prominent rhomboidal subterminal papillae, and a thick right spicule with spoon-shaped distal extremity. The host range of Mansonella was extended to ungulates by the addition of Cutifilaria, which appears to be derived from Tupainema, parasitic in Tupaioidea (insectivores), because of the similarity in their right spicules; Cutifilaria seems to have an Asiatic origin. M. (C.) perforata n. sp. was distinct from the sole other related species, M. (C.) wenki, a parasite of Cervus elaphus (red deer) in Europe, having a more complex right spicule with a sturdy terminal point and microfilariae with a bifid posterior end. In addition, almost all females had cuticular pores near the vulva, on the ventral line. The prevalence of microfiloriae and adults of M. (C.) perforata in the skin of sika deer was 38% and 21%, respectively.