The Apusozoa comprise several genera of flagellate protozoa. 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. There are three orders, often treated as separate groups: the apusomonads, ancyromonads, and hemimastigids. Parasitic excavate (Giardia lamblia) Green algae (Chlamydomonas) PROTISTA KINGDOM Flagellates are members of the Protista Kingdom. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ...

The apusomonads include two genera, Apusomonas and Amastigomonas, and the ancyromonads include one, Ancyromonas. They 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 hemimastigids include three genera, Hemimastix, Spironema, and Stereonema. They are also called the spironemids or Hemimastigophora. Each cell has multiple flagella, arranged in rows from the anterior of the cell towards the posterior.

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. On molecular trees, the apusomonads and ancyromonads group together, but their relationship to other eukaryotes is uncertain. Mitochondria are visible as thread-like structures in the light microscope. ... Cristae are the infoldings of the inner membrane of a mitochondrion. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista Eukaryotes (also spelled eucaryotes) are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ...

References

• David J. Patterson (1999). The Diversity of Eukaryotes. American Naturalist 145: S96-S124.
• Cavalier-Smith, T. (2002). The phagotrophic origin of eukaryotes and phylogenetic classification of Protozoa. International Journal of Systematic and Evoluionary Microbiology 52: 297-354.