Phylum Amoebozoa Lühe, 1913, emend. Cavalier-Smith, 1998
Amoebozoa is a major group of protists which move and feed by means of lobose pseudopodia and which contain mitochondria with tubular cristae. Cells can be naked, covered with a membrane or a loose coat of scales, called tectum, or protected by a more or less rigid test, also called shell or theca. Some species possess cilia (flagella). Tests may be secreted from of organic materials or built up from collected particles as sandgrains and diatom shells cemented together. Most species can form cysts, which may be carried aerially and introduce them to new environments. In slime moulds, these structures are called spores, and form on stalked structures called fruiting bodies or sporangia.
The majority of amoebozoan protists are unicellular, uninucleate, binucleate or multinucleate, and vary in size from about 2 μm to several millimeters in diameter. Slime molds are amoeboid cells which aggregate into multicellular organism which in some species can cover an area of several square meters.
Free-living species are widespread and common in salt, brackish and freshwater, as well as in soil, moss and leaf litter. Some amoebozoa are parasites or live as symbiotes of other organisms. Some are known to cause disease in humans and other organisms.
Amoebozoa form a sister group to animals and fungi.