Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists, often possessing blunt, fingerlike, lobose pseudopods and tubular mitochondrial cristae. In traditional classification schemes, Amoebozoa is usually ranked as a phylum within either the kingdom Protista or the kingdom Protozoa. In the classification favored by the International Society of Protistologists, it is retained as an unranked "supergroup" within Eukaryota. Molecular genetic analysis supports Amoebozoa as a monophyletic clade. Modern studies of eukaryotic phylogenetic trees identify it as the sister group to Opisthokonta, another major clade which contains both fungi and animals as well as several other clades comprising some 300 species of unicellular eukaryotes. Amoebozoa and Opisthokonta are sometimes grouped together in a high-level taxon, variously named Unikonta, Amorphea or Opimoda.
Naegleria is a free living amoebae protist genus consisting of 47 described species often found in warm aquatic environments as well as soil habitats worldwide. It has three life cycle forms: the amoeboid stage, the cyst stage, and the flagellated stage, and has been routinely studied for its ease in change from amoeboid to flagellated stages. The Naegleria genera became famous when Naegleria fowleri, a human pathogenic strain and the causative agent of primary amoebic meningoencephalitis (PAM), was discovered in 1965. Most species in the genus, however, are nonpathogenic, meaning they do not cause disease.
Chaos is a genus of single-celled amoeboid organisms in the family Amoebidae. The largest and best-known species, the so-called "giant amoeba" Chaos carolinensis, can reach lengths of 5 mm, although most specimens fall between 1 and 3 mm.
Difflugia is the largest genus of Arcellinida, one of several groups of Tubulinea within the eukaryote supergroup Amoebozoa. Arcellinida species produce shells or tests from mineral particles or biogeonic elements and are thus commonly referred to as testate amoebae or shelled amoebae. Difflugia are particularly common in marshes and other freshwater habitats.
Discosea is a class of Amoebozoa, consisting of naked amoebae with a flattened, discoid body shape. Members of the group do not produce tubular or subcylindrical pseudopodia, like amoebae of the class Tubulinea. When a discosean is in motion, a transparent layer called hyaloplasm forms at the leading edge of the cell. In some discoseans, short "subpseudopodia" may be extended from this hyaloplasm, but the granular contents of the cell do not flow into these, as in true pseudopodia. Discosean amoebae lack hard shells, but some, like Cochliopodium and Korotnevella secrete intricate organic scales which may cover the upper (dorsal) surface of the cell. No species have flagella or flagellated stages of life.
The Archamoebae are a group of protists originally thought to have evolved before the acquisition of mitochondria by eukaryotes. They include genera that are internal parasites or commensals of animals. A few species are human pathogens, causing diseases such as amoebic dysentery. The other genera of archamoebae live in freshwater habitats and are unusual among amoebae in possessing flagella. Most have a single nucleus and flagellum, but the giant amoeba Pelomyxa has many of each.
Amoeba is a type of cell or organism which has the ability to alter its shape, primarily by extending and retracting pseudopods.
Polychaos dubium is a freshwater amoeboid and one of the larger species of single-celled eukaryote. Like other amoebozoans, P. dubium moves by means of temporary projections called pseudopods. P. dubium reportedly has one of the largest genome size of any organism known, though the authors of a 2004 study suggest treating that measurement with caution.
Amoeba is a genus of single-celled amoeboids in the family Amoebidae. The type species of the genus is Amoeba proteus, a common freshwater organism, widely studied in classrooms and laboratories.
Leptomyxida is an order of Amoebozoa.
Cochliopodium is a Himatismenida genus.
Rhizamoeba is a small genus of free-living marine naked lobose amoebae in the monotypic family Rhizamoebidae in the order Leptomyxida. It is most closely related to Leptomyxa and Flabellula, and some species have been moved to Leptomyxa due to molecular data.
Polychaos is an amoeboid genus in the Amoebozoa group. Several characters unite the species in this genus. The pseudopods meld at their bases when the organism is moving, and have dorsal, longitudinal ridges. The nucleus is oval or ellipsoid.
The vampyrellids, colloquially known as vampire amoebae, are a group of free-living predatory amoebae classified as part of the lineage Endomyxa. They are distinguished from other groups of amoebae by their irregular cell shape with propensity to fuse and split like plasmodial organisms, and their life cycle with a digestive cyst stage that digests the gathered food. They appear worldwide in marine, brackish, freshwater and soil habitats. They are important predators of an enormous variety of microscopic organisms, from algae to fungi and animals. They are also known as aconchulinid amoebae.
An amoeba, often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods. Amoebae do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals.
Nebela is a diverse genus of testate amoebae of cosmopolitan distribution, belonging to the family Hyalospheniidae. They are "prey agglutinated" or "kleptosquamic" organisms, meaning they take the inorganic plates from their prey to construct their test.
Cryptodifflugiidae is a family of arcellinid testate amoebae.
Vampyrella lateritia is a freshwater species of predatory amoebae that feeds on species of algae and is known for its specialized feeding strategy of removing, digesting, and ingesting the cellular contents of its prey. It is the type species of the genus Vampyrella and has been identified in numerous locations around the world including Brazil, Germany, and the eastern United States. Along with Vampyrella pendula, its genome was sequenced in 2012.
Amoebozoa of the free living genus Acanthamoeba and the social amoeba genus Dictyostelium are single celled eukaryotic organisms that feed on bacteria, fungi, and algae through phagocytosis, with digestion occurring in phagolysosomes. Amoebozoa are present in most terrestrial ecosystems including soil and freshwater. Amoebozoa contain a vast array of symbionts that range from transient to permanent infections, confer a range of effects from mutualistic to pathogenic, and can act as environmental reservoirs for animal pathogenic bacteria. As single celled phagocytic organisms, amoebas simulate the function and environment of immune cells like macrophages, and as such their interactions with bacteria and other microbes are of great importance in understanding functions of the human immune system, as well as understanding how microbiomes can originate in eukaryotic organisms.
Mayorella marianaensis is a species of amoebozoan protist discovered in 2023 in Mariana Trench sediments. It belongs to the order Dermamoebida, a group of naked amoebae with a thick glycocalyx.
