Dientamoeba

Small binucleate amoebae (3.5-22 µm) in arrested telophase predominant in populations. Mononucleate individuals with neither flagella nor axostyle throughout the life cycle. V-shaped parabasal body close to the nucleus. Paradesmose stretched between the two polar centres or origin of the parabasal fibres. Ultrastructural studies demonstrated the trichomonad affinities: presence of a parabasal apparatus, a paradesmose as part of an extranuclear spindle originating from atractophores, hydrogenosomes. Basal bodies and axostyle are lacking. The only species known, D. fragilis, is a harmless amoeba, common in the human colon but less numerous than other intestinal amoebae. It forms small spherical cysts. Light microscopy by Dobell (1940) and Wenrich (1944a), diagnosis and ultrastructure in Camp et al. (1974), Honigberg and Brugerolle (1990). Type species: Dientamoeba fragilis.