Trinema complanatum Penard, 1890
Diagnosis: shell broad elliptical, nearly rectangular with rounded corners; compressed, broad elliptical in transverse section. Shell composed of circular to broad elliptical platelets, hardly visible. Aperture normally broad elliptical, invaginated. Nucleus with a central nucleolus.
Dimensions: length 39-49 µm (Penard, 1902); 43-60 µm (Hoogenraad & De Groot, 1940)
Ecology: mosses, Sphagnum, aquatic vegetation, moistened soils.
Remarks: typical specimens are clear to distinguish from Trinema enchelys and Trinema lineare.