Moreneis hexagona is a benthic, pennate diatom found in Korean tidal flats.
From Jinsoon Park et al. 2012
Valves flat, broadly elliptic in outline with protracted, rostrate ends, 22–34 μm long, 11–12 μm wide. Axial area narrowly linear, widening toward the middle of the valve to form a transversely elongated central area. Transapical striae composed of circular areolae, radiate with the occurrence of short areolae in the middle of the valve, 15 in 10 μm. Areolae 18 in 10 μm, along the raphe-sternum somewhat larger and more conspicuous than the remaining areolae. Raphe with a median position in the middle of the valve, slightly eccentric near the apices. Voigt faults distinct, often with the occurrence of a solitary areola. External central raphe endings expanded and grooved, bent in the opposite direction to one another. There is a small dent on the opposite side of each external central raphe ending. Internal central raphe endings straight.