Schoenbornia humicola (Schönborn, 1964)
Diagnosis: Test small, not compressed, hyaline, with Nebela-like irregular siliceous plates and sometimes with quartz particles. Pseudostome circular and without lip or collar. Protoplasm with Euglypha-like layers. Nucleus large, with central nucleolus. Pseudopodia reticulobose.
Dimensions: Length 27-30 µm; width 18 µm, pseudostome 7.5 µm.
Ecology: Numerous in soil of birch forests. Europe.
Remarks: The origin of the plates is not known, though Schönborn assumed that they are idiosomes.