Acanthocystis drakena Zlatogursky, 2016
Diagnosis: Cells are 21.1-30.5 µm (ca. 26.7) in diameter. Cell is covered with oval plate-scales having a margin inflexed to the outer surface. The size of scales is 3.6-8.6 х 2.1-5.0 µm; length/width ratio – 1.1-1.9. Usually scales form a more or less thick and friable layer on the cell surface. Cells passively lay on the substrate or float.
Ecology: An algae-rich ditch. Drakensbergen, Monks Cowl, South Africa.
Remarks: Several species of Raphidiophrys have oval plate-scales: R. intermedia, R. ovalis and R. elegans. R. elegans differs from R. drakena in having curved scales and a tendency for colony-formation. Cells of R. ovalis are twice as large in cell diameter and have much bigger and more elongated scales. The most similar species is R. intermedia, although it has bigger, more elongated scales and larger cell diameter. Also, almost round scales (L/W ratio 1.1) were never observed in R. intermedia, but are present in R. drakena.