Choanocystis punctata  Gerasimova, 2022

Diagnosis: Centrohelids with plate scales and short and long spine scales. Spine scales with hollow and cylindrical shaft tapering to the pointed apex. Short spine scales are 3.6–9.9 μm long, 0.1–0.2 μm thick, eccentrically located at the heart-shaped basal plates (1.0–2.3 μm in diameter), or located almost centrally at the rounded (1.5–2.0 μm in diameter) basal plates. Shafts of the short spine scales can form a curl or small bent hook. Long spine scales are 10.0–18.5 μm long, 0.18–0.3 μm thick, eccentrically located at the heart-shaped basal plates that are 1.0–2.2 μm in diameter. Basal plates of both long and short spine scales are flat, ornamented with numerous granules and marginal rim. In some cases, marginal rim forms two short membranous extensions along the shaft and can form almost triangular membranes. Plate scales are from oval (2.9–4.7 × 1.5–3.2 μm, with axial ridge) to roundish (2.7–4.0 μm in diameter, with well expressed central depression), ornamented with numerous granules and thin marginal rim.

Habitat: Brackish water. Type locality. Bottom sediment from the Tuzlukkol River, salinity 0.6 ppt, South-East of the European part of Russia, N 51°17’3″ E 56°36’21”.