Apusozoa

Apusozoa is a group of single-celled flagellate eukaryotes that Wikipedia describes as a paraphyletic phylum. Its members are small, usually around 5 to 20 micrometres across, and live in soils and aquatic habitats, where they feed on bacteria. What binds them together is an organic shell, or theca, under the dorsal surface of the cell. The name comes from the Ancient Greek words for footless and animal. As traditionally defined the phylum holds two classes, Thecomonadea (the apusomonad flagellates) and Breviatea (the breviate amoebae), each monophyletic, and both sit near the base of the branch that leads to animals and fungi: the opisthokonts appear to have emerged as sister to the apusomonads, and the whole assemblage forms part of the larger clade Obazoa. The apusomonads carry two flagella inserted at right angles near the front of the cell and glide along surfaces with one flagellum trailing. Mitochondrial cristae differ between the orders, which shows that this feature is a poor guide to relationships. The hemimastigotes, once placed here by some classifications, were shown in 2018 research to form their own supra-kingdom.