The central annulus, or ring, of this diatom has an irregular shape. Rows of areolae, or small openings, are gently curved and run parallel to the side row of the sectors, which are wedge-shaped sections of the valve. Labiate processes, which are lip-like structures, are found at the end of these side rows. A small pseudonodulus, or thickening, is located near the mantle, the edge of the valve.The diameter of these organisms falls within the range of 13-160 micrometers (µm). In a 10 µm span, there are typically 8-18 areolae, and the distance between the marginal processes measures around 7-9 µm.