Plagiopyxis barrosi  Bonnet, 1960

Diagnosis: Shell dark yellow to beige, circular in shape in dorsal view. In lateral view, the ventral side, strongly sloping, folds up to almost come into contact with the dorsal side, leaving a relatively wide vestibule communicating with the body through a semi-elliptical internal opening. The suture between visor and ventral side is reinforced laterally by two brownish chitinoid thickenings visible in apical view and sometimes in ventral view. The dorsal lip of the visor is extended by a kind of median tongue narrowing the opening of the pseudostome. Shell wall made up of irregular, exogenous siliceous elements, embedded by a yellowish chitinoid cement which also incorporates some blackish particles of various sizes.

Dimensions: Shell diameter 55-60 µm; dorso-ventral (height): 32-36 µm.

Ecology: Soil. Angola, Africa.

Remarks: The dorsal view is quite similar to that of Plagiopyxis callida Pénard. The apical view and the structure of the pseudostome make it easy to differentiate the two species.