Genus Parachaos Willumsen, Siemensma & Suhr-Jessen, 1987

Diagnosis: Locomotive form commonly polypodial, 100 to 500 µm, or monopodial up to 900 µm in length. Multinucleate with 8 to 50 spherical, or slightly oval, nuclei per cell. Nucleolar material parietal as single layer or irregular fragments or a central nucleolus. Cytoplasm rich in bipiramidal or plate-like crystals and zoochlorellae in many isolates. Usually with villous-bulb uroid. No dorsal or lateral ridges.

Type species. Parachaos zoochlorellae (Willumsen, 1982)

Habitat: Freshwater.

Remarks: Similar to Chaos but dorsal and lateral ridges are absent and at the ultrastructural level Parachaos can be distinguished by an amorphous cell coat without filaments and nuclei with no internal laminae.