Genus Nuclearia Cienkowsky, 1865
Diagnosis: Cell amoeboid, normally spherical to subspherical, with sharply pointed fine radiating pseudopodia; actively moving form varies in shape; cell readily adopt a flattened form without severe compression being applied; branching of pseudopodia occurs; with or without a mucous envelop; with one or many nuclei.
Ecology: Fresh water. Feeding by either ingestion of food particles or penetration of eukaryotic algal filaments.
Key to the species:
Note: the weak point of this key is that it is very difficult to detect any nucleus in a Nuclearia-species.