Acta Societatis Scienctiarum Fennicae, Nova Series B, 2 (6): 17 (Grönblad 1945).
DISTRIBUTION. — North and South America. Amazon Basin: Thomasson (1971); Thérézien (1986); Cadima (2013). Western Amazonia (lowlands): Krieger & Scott (1957).
Cells 196.2-212.0 µm long, 126.0-127.0 µm wide, isthmus 40-42 µm; cells 1.5-1.7 times longer than wide. Cell wall denticulate throughout each semicell, with denticles almost always pointing towards apices; central part of semicells with spines and granules (Fig. 2E). Semicells triangular, with rounded basal angles, straight to slightly convex lateral margins, converging towards the apex of each semicell, and slightly convex to subtruncate apical margins.