Archamoebae Cavalier-Smith 1983

Diagnosis: Amoebozoa distinguished by the absence of mitochondria, which are converted to non-aerobic organelles. Archamoebae are closely related to the slime moulds.

Two groups can be distinguished:

Entamoebids are internal parasites or commensals of animals (Entamoeba and Endolimax). A few species are human pathogens, causing diseases such as amoebic dysentery.

Pelobionts inhabit freshwater and are unusual among amoebae in possessing cilia. Some have a single nucleus and cilium, but Pelomyxa species can have many of each.

Pelobiontida Page, 1976

Pelomyxa Greeff, 1874

Diagnosis: Multiple cilia; anaerobic; polymorphic life cycle with multinucleate stages; with symbionts.

Mastigamoebaea Frenzel, 1892

Diagnosis: Amoeboid with several pseudopodia; sometimes body without amoeboid motion, depending on conditions; single cilium directed forward, with vibrating beat; single kinetosome with cone of microtubules extending to nucleus; uninucleate, but some species multinucleate; large nucleoli persist through division with intranuclear spindle; stages without cilium occur; cysts; occurring in micro-aerophilic to anaerobic habitats rich in dissolved nutrients.
I30ertae sedis Mastigamoebaea: Endolimax, Mastigina.

Entamoebidae Chatton, 1925, emend. Cavalier-Smith, 1993

Diagnosis: Cilium and centrioles absent; with mitosomes instead of classical mitochondria; peroxisomes absent; mitosis closed with endonuclear centrosome and spindle; reduced Golgi dictyosome. Note that this diverse genus could potentially be subdivided into other genera. Entamoeba.