Cyclopyxis impressa (Daday, 1905) Da Cunha, 1913
Difflugia lobostoma var. impressa Daday, 1905

Diagnosis. Shell in dorsal view circular, in side view it resembles a somewhat flattened hemisphere; the dorsal side is a bit bulbous; the ventral side is flat with a funnel-like invagination with the aperture. At the outer edge of the funnel is a more or less horizontal brim whose width is 1/3 or 1/4 of the whole shell diameter. The aperture is surrounded with 6-8 pointed chitinous teeth, dark brown or blackish gray, separated from each other by curves. Shell embedded with mineral grains and particles.

Dimensions: According to Daday (1905): Shell diameter 300—450 µm; height 100—150 µm; diameter of the funnel 150—190 µm.

Ecology: Freshwater.Sediment.

Geographical distribution: South-America (Asuncion, Lagoon (Pasito), inundations of the Paraguay River; Sapucay, Arroyo Pona, inundations of a stream; Tebicuay, pond.)