Trigonopyxis microstoma Hoogenraad and De Groot, 1948
Diagnosis: Shell relatively large, circular in dorsal view, sometimes elliptical. The ventral side of the shell is flat and only in the center there is a small depression with the aperture which is small and irregularly-shaped, surrounded by a more or less organic lip.
Dimensions: Shell diameter 80-130 μm, height 52-60 μm, diameter of the aperture 10-17 μm.
Ecology: Sphagnum, moist mosses. Patagonia.