Genus Lecythium Hertwig & lesser, 1874 emend. Dumack et al., 2016
Diagnosis: Filose, radially symmetric amoebae. Cells bear a colourless, thin and organic test (theca), carried in an upright position, with one basal opening from which branching and anastomosing filopodia arise. Filopodia may show small granules. Nucleus at the apical end of the cell. Cells with numerous contractile vacuoles and granules. Might form floating or swimming stages (single cells and aggregates) with straight, non-branched and non-anastomosing filopodia. Aggregates with fused filopodia or fused vacuolated cytoplasm occur. Cysts are built within the theca that then remains as a loose envelope around the cyst wall. No flagellated cells observed. Species feed on eukaryotic prey (i.e. algae); ingestion of bacteria not observed. Division: longitudinal, binary. Sexual reproduction unknown.
Type species: L. hyalinum
Dimensions: mostly small species.
Ecology: common in different types of water; feeding on algae and bacteria.
Remarks: Nucleus and pseudostome are difficult to observe, the latter is usually a small hole between folds.