Thecamoeba similis (Greeff, 1891) Lepşi, 1960

Diagnosis: Surface moderately wrinkled in stationary amoebae, becoming smoother in locomotion, usually with a few peripheral wrinkles, sometimes with a few dorsal folds converging somewhat posteriorly; outline in locomotion usually oval, broad or somewhat elongate, sometimes narrowing toward pyramidally hump-like posterior end; hyaloplasm a rather broad antero-lateral crescent; nucleus usually ovoidal or ellipsoidal with numerous small endosomal, clearly discrete pieces in peripheral zone beneath nuclear membrane; a single contractile vacuole, with diameter to 13 µm.

Dimensions: Page (1977): length ca. 30-80 µm (mean 46-57 µm); length-breadth ratio 0.8-1.8; nucleus 7.7-13.9 µm.

Ecology: Freshwater, soil and mosses. Observed food: bacteria, other amoebae and fungi spores (Page, 1977), diatoms.

Remarks: This species can be confused with T. foliovenanda, T. striata, which has less numerous pieces of nucleolar material, and with T. terricola, which has a more elongated nucleus. This amoeba is typically broader than most other species of Thecamoeba.