The Apusozoa are a paraphyleticphylum[1] of flagellateeukaryotes. They are usually around 5–20 μm in size, and occur in soils and aquatic habitats, where they feed on bacteria. They are grouped together based on the presence of an organic shell or theca under the dorsal surface of the cell.
The name derives from the Ancient Greek words for footless (ἄπους) and animal (ζῷον).[2][3]
This phylum is currently defined as containing the Breviata and the Apusomonadida.[4][5] However, it currently usually is viewed as paraphyletic, with the Breviata as more basal. The opisthokonts appear to have emerged as sister of the apusomonadida. It has been suggested that the Mantamonadida be classified in Apusozoa.[6][7]
The apusomonads have two flagella inserted at right angles, near the anterior of the cell. They move by gliding, with one flagellum trailing along the side and one directed to the anterior.
The form of the mitochondria varies between the different orders. Among the apusomonads they have tubular cristae, the ancyromonads flat cristae, and the hemimastigids ambiguous or sacculate cristae. This characteristic was originally considered a good indicator of relationships, but is now known to vary even among close relatives.
^Cavalier-Smith T, Chao EE, Stechmann A, Oates B, Nikolaev S (October 2008). "Planomonadida ord. nov. (Apusozoa): ultrastructural affinity with Micronuclearia podoventralis and deep divergences within Planomonas gen. nov". Protist. 159 (4): 535–62. doi:10.1016/j.protis.2008.06.002. PMID18723395.
^Glücksman E, Snell EA, Berney C, Chao EE, Bass D, Cavalier-Smith T (September 2010). "The Novel Marine Gliding Zooflagellate Genus Mantamonas (Mantamonadida ord. n.: Apusozoa)". Protist. 162 (2): 207–221. doi:10.1016/j.protis.2010.06.004. PMID20884290.
^Orr, Russell J. S.; Zhao, Sen; Klaveness, Dag; Yabuki, Akinori; Ikeda, Keiji; Makoto, Watanabe M.; Shalchian-Tabrizi, Kamran (2017-10-08). "Enigmatic Diphyllatea eukaryotes: Culturing and targeted PacBio RS amplicon sequencing reveals a higher order taxonomic diversity and global distribution". bioRxiv10.1101/199125.
^Cavalier-Smith, Thomas (2003-01-01). "Protist phylogeny and the high-level classification of Protozoa". European Journal of Protistology. 39 (4): 338–348. doi:10.1078/0932-4739-00002. ISSN0932-4739.
^Adl SM, Bass D, Lane CE, Lukeš J, Schoch CL, Smirnov A, Agatha S, Berney C, Brown MW, Burki F, Cárdenas P, Čepička I, Chistyakova L, del Campo J, Dunthorn M, Edvardsen B, Eglit Y, Guillou L, Hampl V, Heiss AA, Hoppenrath M, James TY, Karnkowska A, Karpov S, Kim E, Kolisko M, Kudryavtsev A, Lahr DJG, Lara E, Le Gall L, Lynn DH, Mann DG, Massana R, Mitchell EAD, Morrow C, Park JS, Pawlowski JW, Powell MJ, Richter DJ, Rueckert S, Shadwick L, Shimano S, Spiegel FW, Torruella G, Youssef N, Zlatogursky V, Zhang Q (2019). "Revisions to the Classification, Nomenclature, and Diversity of Eukaryotes". Journal of Eukaryotic Microbiology. 66 (1): 4–119. doi:10.1111/jeu.12691. PMC6492006. PMID30257078.