Cyclopyxis machadoi Bonnet, 1965
Diagnosis: Test large, clear, circular in ventral view; in side view more than hemispherical: about 2/3 circular. Pseudostome abrupt, quite strongly invaginated. The ventral side of the pseudostome has a tubular section, inwardly forming 2-4 large, usually 3, vertical ribs, which in ventral view, appear lobes.
Covering strongly refractive, formed by large hyaline lenticular scales, sometimes corroded, and obviously modified. The appearance of the covering is reminiscent of Heleopera sylvatica Penard, but the elements of Cyclopyxis machadoi are stacked on two or three thicknesses. The scales are more regular on the ventral side; the dorsal part has irregular platelets, but still more or less reworked, and sometimes vermiculated as with Lesquereusia spiralis.
Dimensions: Bonnet: diameter 180 to 220 µm; height: 165-180 µm. Diameter of the pseudostomal tube about 1/5 of test diameter. Height of pseudostomal tube: about 1/4 of the height of the test.
Ecology: This species is common in all soils rich in organic matter of Angola (gallery forest, grass), the Republic of Congo (savannah on quartz sandstone, forest soil on limestone, on feldspathic sandstone), Gabon (floors various forest).