Mastigamoeba

Amoeboid cells with a flagellated basal body located immediately adjacent to the anterior nucleus. The nucleus may be pulled out anteriorly to have a conical appearance. The connection may be seen with the light microscope. The flagellum is long and directed forward, the pseudopodia are simple, branched, or absent. The cells may swim or glide. Life cycles may include amoeboid organisms, multinucleated cells, or cysts. Electron-microscopical studies have shown that a cone of microtubules connects the short basal body to the nucleus and that there is a ribbon of microtubules extending from the basal body into the cytoplasm. The flagellum has the conventional 9+2 arrangement of microtubules within the axoneme, but variations on the normal organization of the basal body have been reported. The monotypic genus Phreatamoeba was erected by Chavez et al. (1986) for organisms with a complex life cycle. Phreatamoeba cannot be distinguished from Mastigamoeba and thus is a synonym of Mastigamoeba. Dinamoeba mirabilis Leidy, 1874, the type species of that genus, also appears to be an incomplete description of Mastigamoeba aspera (Simpson et al., 1997). With about 40 nominal species, many of which will prove to be incomplete descriptions of other species. Type species: Mastigamoeba aspera Schulze, 1875.