Genus Clypifer Shishkin, 2021

Diagnosis Pterocystid centrohelids with one type of siliceous plate scales composed of a single plate, without septae and hollow chambers inside.
Type species: Clypifer cribrifer Shishkin, 2021

Clypifer cribrifer Shishkin, 2021

Diagnosis: The cell body diameter is around 4–10 μm. Axopodia are more often two to three cell diameters long. The cell body and the bases of the axopodia are covered with plate scales. Scales are elliptical, circular, more rarely ovoid, hourglass-shaped or asymmetric. Scales are around 0.8–2.3 μm long and around 0.6–1.8 μm wide. The majority of scales is fenestrated to some extent with irregular holes. A very short, and usually arcuate, axial rib is located on the proximal surface of scales. The central area around the axial rib is usually less fenestrated than the zone closer to the edges. There is a hole in the central area of the scale, partly covered by the axial rib arc. Often there are four radial folds in the direction of the axial rib. The edges of scales are bent inward and form a marginal rim protruding on the distal side of scales.