Acanthocystis olgashelestae  Leonov, 2010

Diagnosis: Cells are 13-16 µm in diameter. Periplast with tangential plate-scales and radial spine-scales. Spine-scales 2.2-5.8 µm long, apex bearing 2 marginal teeth. The shaft, 0.11 μm thick, attaches to a rounded basal plate 0.4 μm in diameter. Lamellar scales are oval or pear-shaped, 1.3-1.8 x 1.0-1.2 µm in size, the surface is ornamented with small randomly arranged granules.

Habitat: Freshwater. Voronezh region, Russia.

Remarks: It is similar in shape and ornamentation of lamellar scales to A. pectinata (Penard 1889), but differs from it in size and shape of the spine-scales. The spine-scales of A. pectinata are divided into long (6.0-10 µm) and numerous short (2-3 µm) spine-scales, characterized by complex ornamentation of the tops.