Plagiopyxis coiffaiti Bonnet, 1965

Diagnosis: Shell elliptical in dorsal view, with the major axis clearly larger than the minor axis. A border, visible in the anterior third, marks the location of the partition which separates the main body from the visor. In lateral view, the ventral side or sole is perfectly flat. In ventral view, the visor opens, at the level of the sole, by a thin crack whose lips are formed by the fold of the visor downwards (dorsal lip) and the ventral face of the body flattened in sole (ventral lip). The communication between main body and visor is established by means of an aperture pierced on the partition separating these two cavities. The structure is therefore comparable to that of Plagiopyxis callida and particularly to that of the variety pusilla, but in the latter the test is circular and can even stretch in the direction of the width. Shell yellowish or brownish, very smooth, very regular, made up of reworked quartz elements so intimately united that it is difficult to distinguish their limits.

Dimensions: Length 77-80 µm; width 50-55 µm; dorso-ventral (height) 45-50 µm.

Ecology: Soil. Extremely common in all soils rich in organic matter in West-Africa. It seems quite distinctly eurytopic.