Genus Polychaos Schaeffer, 1926
Diagnosis: during active locomotion usually polypodial, palmate, with several tubular pseudopodia, more or less equal and with no one dominant, proceeding anteriorly and anterior-laterally from common posterior mass; posterior of cell often with a bundle of fused, remnant pseudopodia; pseudopodia sometimes flattened and broadening towards ends; monopodial in rapid locomotion with a bulbous uroid; no dorsal ridges; nucleus granular or with other arrangements of nucleolar material; crystals irregular or plate-like to bi-pyramidal, some as paired bodies or clusters.
Key to the species:
| 1 | Nucleus with a ring- or belt-shaped nucleolus | 2 |
| – | Nucleus granular | 3 |
| 2 | Nucleolar material in few narrow peripheral lobes, sometimes in a single curved band, twisting inside the nucleus. | P. fasciculatum |
| – | Nucleolar material forming a perforated sphere inside the nucleus. | |
| 3 | Nucleus discoid, spheroid or ovoid | P. dubium |
| – | Nucleus shallowly to deeply cup-shaped | P. nitidubium |
Polychaos fasciculatum