phylum of protozoans

The Amoebozoa are a eukaryote phylum of Amoeba-like protozoa.[2] Most move by internal cytoplasmic flow. Their finger-like pseudopodia are characteristic.

Temporal range: 1000–0 Ma[1]
Chaos carolinense.jpg
Chaos carolinensis
Scientific classification e
Domain: Eukaryota
(unranked): Unikonta
Phylum: Amoebozoa
Lühe, 1913 emend. Cavalier-Smith, 1998
Subphyla, infraphyla and classes
  • Eumycetozoa Zopf 1884, emend Olive 1975

They are a major group with about 2,400 described species of amoeboid protists.[3][4][5] In most classification schemes, Amoebozoa is ranked as a phylum in either the kingdom Protista[6] or the kingdom Protozoa.[7] In the classification of the International Society of Protistologists, it is kept as an unranked "supergroup" in the Eukaryota.[4]

Sequence analysis shows Amoebozoa is a monophyletic clade. Most phylogenetic trees identify it as the sister group to Opisthokonta. That is another major clade which contains both Fungi and Animals as well as some 300 species of unicellular protists.[3][8] Amoebozoa and Opisthokonta are sometimes grouped together in a high-level taxon, variously named Unikonta,[7] Amorphea,[4] or Opimoda.[9]

Amoebozoa includes many of the best-known amoeboid organisms, such as Chaos, Entamoeba, Pelomyxa and the genus Amoeba itself.

Most are unicellular, and are common in soils and aquatic habitats. Some are symbionts of other organisms, including several pathogens. The Amoebozoa also include the mycetozoan slime moulds, multinucleate or multicellular forms which produce spores and are usually visible to the unaided eye.[10]

The nutrition is usually by phagocytosis. The cell surrounds food particles, sealing them into vacuoles where they are digested and absorbed. When food is scarce, most species form cysts, which may be carried by air to other places. In slime moulds, these structures are called spores, and form on stalked structures called fruiting bodies or sporangia.

Most Amoebozoa lack flagella and more generally do not form microtubule-supported structures except during mitosis. However, flagella occur among some archamoebae, and many slime moulds produce biflagellate gametes.

A characteristic form is the model organism Dictyostelium discoideum.


  1. Parfrey LW, Lahr DJ, Knoll AH, Katz LA (August 2011). "Estimating the timing of early eukaryotic diversification with multigene molecular clocks". Proceedings of the National Academy of Sciences of the United States of America. 108 (33): 13624–9. doi:10.1073/pnas.1110633108. PMC 3158185. PMID 21810989.
  2. Patterson, David J. 1999. The diversity of eukaryotes. American Naturalist 154 (S4): S96–S124 [1].
  3. 3.0 3.1 Pawlowski J. 2012; et al. "CBOL Protist Working Group: barcoding eukaryotic richness beyond the animal, plant, and fungal kingdoms". PLOS biology 10(11). doi:10.1371/journal.pbio.1001419.
  4. 4.0 4.1 4.2 Adl S.M.; et al. (2012). "The revised classification of eukaryotes". Journal of Eukaryotic Microbiology. doi:10.1111/j.1550-7408.2012.00644.x. PMID 23020233. Retrieved April 7, 2015.
  5. Cavalier-Smith T.; et al. (2015). "Multigene phylogeny resolves deep branching of Amoebozoa". Molecular Phylogenetics and Evolution. doi:10.1016/j.ympev.2014.08.011. Retrieved April 7, 2015.
  6. Corliss, John O. (1984). "The Kingdom Protista and its 45 phyla". BioSystems 17.2 (1984): 87-126. doi:10.1016/0303-2647(84)90003-0. Retrieved April 7, 2015.
  7. 7.0 7.1 Cavalier-Smith, Thomas (2003). "Protist phylogeny and the high-level classification of Protozoa". European Journal of Protistology. doi:10.1078/0932-4739-00002.
  8. Cavalier-Smith; et al. (2015). "Multigene phylogeny resolves deep branching of Amoebozoa". Molecular Phylogenetics and Evolution. doi:10.1016/j.ympev.2014.08.011. Retrieved April 7, 2015.
  9. Derelle; et al. (2015). "Bacterial proteins pinpoint a single eukaryotic root". Proceedings of the National Academy of Sciences. doi:10.1073/pnas.1420657112.
  10. Schilde C. & Schaap P. 2013. The Amoebozoa. Methods Mol. Biol. 983, 1–15. [2]