Pyxidicula gigantea  Decloitre, 1965

Diagnosis: Species characterized by its very large size (360–400 µm in diameter) and nearly circular outline. The central region is dark yellow, surrounded by a lighter yellow zone, itself enclosed by a nearly transparent outer portion. The dark yellow area corresponds to the endoplasm, while the transparent region represents the ectoplasm. The nucleus is nearly central, approximately 70 µm in diameter, with two large nucleoli. The membrane is composed of very fine, irregularly hexagonal areoles. In apical view, the pseudostome nearly coincides with the boundary of the ectoplasm. The central part of the test appears to lack areoles. Where the membrane is bare, it is highly transparent and devoid of coloration.

Dimensions: According to Decloitre (1965): shell diameter 360—400 µm.

Ecology: Freshwater, oligotrophic.

Geographical distribution: Iceland, 1933.