Cells may be found individually or in short chains, connected by spines originating from the valve surface. These spines are relatively long and differ from O. regia and O. sinensis by being closer to the valve’s center. When viewed from above, the cells have an elliptical to elliptical-lanceolate shape, while in girdle view, they appear roughly rectangular with a broad girdle. The valve’s corners extend into long, straight tubular processes, which are typically shorter than the spines located in the raised valve center. These tubular processes point outward and have blunt, rounded tips, which remain consistently wide. Healthy cells contain numerous granular, plate-like chloroplasts. The valves are only mildly silicified and often break when mounted permanently. The valve’s fine areolation consists of 14-16 areolae in a 10 µm area. In broad girdle view, the centrally positioned nucleus is usually visible.