Plagiopyxis angularis Bonnet, 1960

Diagnosis: Shell clear, transparent, elliptical in shape in dorsal view. In lateral view, the dorsal membrane forms, in the posterior part of the test, a right angle with the ventral membrane. This, very slightly sloping over most of its surface, constitutes a particularly clear ventral sole and bends sharply inside the test, leaving a fairly large vestibule. The pseudostome, in a narrow fissure, is located in the anterior third of the test. Shell covered with irregular siliceous elements united by a hyaline cement incorporating, in addition, a few fine particles.

Dimensions: Length 40-48 µm; width 35-40 µm; dorso-ventral (height) 24-26 µm.

Ecology: Soil. Rhizosphere of grasses on mica schists (Eastern Pyrenees).

Remarks: This species is distinguished from Plagiopyxis minuta by the angle of connection of the ventral surface and the dorsal surface, as well as by the pronounced inflection of the ventral lip.