Rotosphaerida Rainer, 1968
Diagnosis: Aciliate predominantly spherical or flattened amoebae from which elongated actin-based filopodia extend; with flat discoid mitochondrial cristae; uninucleate or polynucleate (with few nuclei); free-living phagotrophs that feed on bacteria, cyanobacteria and algae.
Some sorocarpic, e.g. F. alba; some have symbionts, e.g. N. thermophila, Fonticula, Nuclearia, Parvularia.
Incertae sedis Rotosphaerida: Pompholyxophrys, Lithocolla, Vampyrellidium, Pinaciophora, Rabdiophrys, Rabdiaster.