world of amoeboid organisms

Chaos carolinense
A polypodial form; B monopodial form; C crystals (drawing Ferry Siemensma)

Chaos spec.

Diagnosis: locomotive amoebae usually polypodial; in rapid locomotion monopodial; pseudopodia usually with ridges and wings; floating form irregular rounded with some long lobopodia; uroid morulate; multinucleate, with up to 120 nuclei; nuclei spherical, ovoid, biconcave or biconvex disks, with granular nucleolar material; cytoplasm usually with bipyramidal crystals, or mixed with plate-shaped crystals; cysts observed.

Dimensions: monopodium 700-1600 µm; nuclei 9.6-48 µm (mean 22 µm); crystals ca. 2.2 µm, sometimes up to 7.9 µm.

Ecology: often abundant in floating debris from ditches and ponds. In early spring debris from the bottom can float by activity of blue algae which form gas bubbles.

Remarks: I have found many specimens in the Netherlands (around Kortenhoef and in Dwingelo) and some in England (Cambridge, pond) and Sweden (Mörrum, river). A very rich population was present in a ditch between Kortenhoef and Loosdrecht in May 1985. I got some specimens in cultures on maize grains, which survived for many years. In older cultures cysts showed up.

I’m not sure if all the observed specimens belong to one species.

The number of nuclei and their size and shape can be very different. There might be a correlation between number and size. Usually specimens with few nuclei have larger ones than species with numerous nuclei. For example: in a specimen with three nuclei their size was 36 µm, in a specimen with 119 nuclei the size was 9.6 µm. Larger nuclei tend to be discoid and smaller nuclei are usually spherical.

I have seen a lot of specimens of this Chaos species, but the number of nuclei never exceeded 120.

Chaos carolinense
C heavily disturbed amoeba; D Cyst. (drawing Ferry Siemensma)
Chaos carolinense nuclei
Nuclei: several shapes and structures (drawing Ferry Siemensma)
Dutch chaos amoeba
Two discoid nuclei in lateral view. The nucleolar material is peripherally arranged.
Chaos-amoeba with concave discoid nuclei.
chaos grafiek nuclei
Distribution of nuclei in 338 specimens of the Dutch Chaos spec. in one culture
Dutch chaos amoeba
Variation in size within 169 nuclei from several amoebae of the Dutch Chaos spec. in one sample
Dutch chaos amoeba
Examples of the many shapes of Chaos spec.
Dutch chaos amoeba
Chaos in polypodial locomotion with ca. 8 nuclei visible.
Dutch chaos amoeba
Chaos amoeba in monopodial locomotion.
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