Amphora copulata

Valves are semi-lanceolate to semi-elliptical. The dorsal margin is smoothly arched and the ventral margin is concave. Valve ends are narrowly rounded. The axial area is narrow. The raphe is arched and positioned toward the ventral margin. The proximal and distal ends of the raphe are both dorsally deflected. Dorsal fascia are distinct and round to elliptical. The dorsal fascia are typically “closed” to the axial area and dorsal margin by a row of short striae. The ventral fascia are typically longer (in the apical axis) than dorsal fascia. The ventral fascia extend to the ventral margin. Dorsal striae are weakly radiate in the central area, becoming more radiate at the apices. The dorsal striae are interrupted by intercostal ribs. A thickened, hyaline bar is often visible on the dorsal margin separating valve face and mantle. The ventral striae are uninterrupted. The ventral striae are radiate in the middle, convergent toward the apices, and consist of a single areola.