O. massinoi Witenberg, 1926

Type host. Unknown species of “wild duck” ( Anseriformes: Anatidae).

Type locality. Turkestan, Russian Federation; specific type locality unknown. Remarks. Considered to be a synonym of O. singularis (Stossich, 1902) by Dubois (1959). No oral or ventral sucker described—Witenberg (1926).