Mallomonas multisetigera Durrschmidt

Mallomonas multisetigera Dürrschmidt Figs 1 C, D, 3 Description. Cells ellipsoidal, 8.6–13.5 × 3.7–7.9 μm, covered by scales with bristles. Body scales oval, 2.3–3.5 × 1.2–1.7 µm, tripartite. Shield with regularly arranged papillae and scattered minute base plate pores (0.01–0.03 μm). Sometimes larger pores can be observed on the shield. The dome is shallow, broadly oval, set back from the anterior margin, and covered with papillae. The V-rib is conspicuous, acute, and hooded. The posterior rim is narrow, encircles less than a half of the scale perimeter. The posterior flange is wide, with two rows of large base plate pores (0.03–0.08 μm). The anterior flange with two or three rows of papillae and often with a few large base plate pores continuing from the posterior flange. Anterior scales are asymmetric, widened in the distal part, with elongated dome and have the same basic structure as body scales. Bristles are 2.6–5.0 µm. The foot of the bristle is flattened, turned at an angle of approximately 45 degrees or less relative to the shaft, the margins of the bristles are rolled to form an open U-shaped groove, the distal tip is bifurcated, with spines of unequal length. Cysts were not observed. Observations. Mallomonas multisetigera was found at wide ranges of environmental parameters: pH from 4.7 to 7.2, specific conductance from 25 to 2730 µS cm - 1, and temperature 29–39 ° C (Table 1, and see Gusev et al. 2023 b).