Diagnosis: locomotive amoebae usually polypodial, like a dead tree with thick truncate branches; in rapid locomotion monopodial. Polypodial forms 360-600 µm; monopodial forms up to 1300 µm; pseudopodia usually with ridges; uroid morulate; multinucleate, nuclei spherical, discoid, concave or convex shaped, 9.6 - 48.0 µm (mean 22 µm; 2-119 nuclei (mean 27 µm) per amoeba; crystals bipyramidal and plate-like, 2.2 µm, sometimes up to 7.9 µm; cysts observed.
Ecology: fresh water, ponds and rivers, especially in floating debris in early spring. Not rare.
Remarks: I have collected populations of Chaos with both multinucleate and uninucleate specimens!
I have sampled and observed a large number of Chaos-specimens in the Netherlands (several wide spread locations), Sweden (Mörrum-river) and Engeland (Cambridge, pond). All these amoebae had, even within a population, spherical, discoid or convex shaped nuclei, varying in size from 9.6-48.0 µm.