Diagnosis: Locomotive form usually between 75 and 500 µm in length. Pseudopodia cylindrical and smooth with clear hyaline zone. Cytoplasm often very granular with bipyramidal or irregular crystals. Nucleus discoid or spherical, filled with granules of nucleolar material. Uroid often typically elongated, U-shaped, papillate or morulate and temporary. No dorsal folds.
Dimensions: monopodium 350-560 µm; nucleus 33-70 µm (mean 42 µm)
Ecology: Freshwater. I have found this species on several locations in the Netherlands (Baarn, Naardermeer, Roden, Diepveen-Dwingeloo) and in Tirol, Austria. It could easily be cultured with “pond” culture.
Remarks: This species is remarkable because of the density of crystals, which gives it usually a dark and black appearance, though some specimens were observed with the same density of crystals as is normal for Amoeba proteus. Its shape can differ strongly. Between cover slip and slide the amoebae are less slender as in culture dishes.
The drawings below were made around 1980 from specimens which I found on several locations in the Netherlands.