(Manguin ex Kociolek and Reviers) Potapova, Aycock and Bogan 2020
Valves < 7 μm in diameter
Striae cover 50-70% of valve radius
Central rosette present, or absent
Cells are less than 7 μm in diameter. The striae on the valve face extend along 50–70% of the valve radius. A central rosette of alveoli is variable, as it may be present or absent.