Cyclopyxis lithostoma Bonnet, 1974
Diagnosis: Test large, more or less dark brownish, in dorsal view circular. In side view, ventral sole very individualized. Height approximately 2/3 of shell diameter. Transition between dome and sole arc-shaped, not angular. In ventral view, pseudostome at the end of a shallow conical depression. Aperture very irregular, lined with large siliceous elements arranged without order on the ventral sole. These elements sometimes narrow the aperture almost completely.
In some individuals, the depression has only small elements embedded in a brownish chitinoid cement. Test covered with a mixture of elements, partly exogenous (quartz fragments) and partly endogenous (amorphous siliceous particles reworked into irregular shaped platelets). Within the test, the periphery of the ventral sole comprises in some individuals an annular chitinoid dark brown reinforcement, sometimes inconspicuous.
Dimensions: Bonnet: Ø average: 152 µm; SD: 6 µm. (n=20).
Ecology: Common species in upland savanna soils in the grass root zone (Loudetia, Hyparrhenia).