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Amoeba proteus
Amoeba proteus

Amoeba proteus (Pallas, 1766) Leidy, 1878

Diagnosis: Locomotive cells, often 220 to 760 µm in length; usually polypodial with one dominant pseudopodium, usually with dorsal and lateral folds or ridges; resting or well fed, cells irregularly rounded; floating forms wit h long radiating pseudopodia; cytoplasm granular in appearance, often with truncated bipyramidal or plate-shaped crystals; posterior uroid morulate; nucleus discoid or ovoid, sometimes with peripheral granules; nucleolar material often scattered.

Dimensions: 220-760 µm (mean 425 µm); nucleus 22-62 µm (mean 38-47 µm), discoid, often biconcave.

Ecology: freshwater and wet Sphagnum, in different types of water. Not rare.

Remarks: Though this amoeba has been described as uninucleate, I have often seen multinucleate specimens. In one sample there were amoebae with one nucleus and specimens with several nuclei (see the graph below.)

Amoeba proteus
Amoeba proteus, polytactic form 400 µm – quaking bog, Bert Bospad
Amoeba proteus, monotactic form, with two nuclei
Amoeba proteus, c. 830 µm long
Amoeba proteus
Amoeba proteus
Nucleus c. 42 µm, and the same nucleus in lateral view
Amoeba proteus
Amoeba proteus
Nucleus, lateral view
Amoeba proteus
Amoeba proteus
Nucleus, lateral view
Amoeba proteus
Amoeba proteis
Nucleus, irregular outline
Amoeba proteus
Amoeba proteus
Nucleus, lateral view, 40 µm, nucleus, lateral view, 42 µm
Amoeba proteus

 

Amoeba proteusA-C polypodial locomotion; D monopodial locomotion; E amoeba in preparation for division; bipyramidal crystal; G plate-shaped crystal; clustered crystals.
Amoeba proteus
floating form; B amoeba changing from floating form to Cnumber of nuclei per amoeba; E-N different shapes of nuclei: G-N lateral view.
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