Type host. Water rail, Rallus aquaticus Linnaeus (Gruiformes: Rallidae).
Type locality. Russian Federation; specific type locality unknown.
Additional hosts. Glossy ibis, Plegadis falcinellus Linnaeus (Pelicaniformes: Threskiornithidae); little ringed plover, Charadrius dubius curonicus Gmelin (Charadriiformes: Charadriidae) (northern subspecies of Charadrius dubius Scopoli)—(Yamaguti 1958, 1971).
Additional locality. Japan; specific locality unknown—Yamaguti (1971).
Previously proposed synonym. Ophthalmophagus massinoi Witenberg, 1926 — Bashkirova (1950).
Remarks. Considered a possible synonym of O. singularis (Stossich, 1902) by Dubois (1959). Joyeux & Baer (1927) considered this to be a species of Spaniometra. No oral or ventral sucker described—Witenberg (1923, 1926).