Kobayasiella okadae

Valves are linear-lanceolate with short, capitate apices. Apices are about one-half the width of the valve. The axial area is narrow and nearly linear, the narrowest point being where the valve margins constrict to form the apices. From this narrow point the axial area flares abruptly towards the valve apex, and, in the other direction, very gradually towards the central area. The central area is small, barely wider than the axial area, and elliptical in shape. The raphe is filiform. A section of each external raphe branch becomes indistinct about mid way between the valve center and the apex. Proximal raphe ends are straight and lie in spathulate depressions, which make them appear expanded in LM. Distal raphe ends are strongly curved towards the secondary side, where prominent Voigt discontinuities are evident in SEM. Striae are radiate, becoming convergent and more closely spaced near the apices. Striae are interrupted by longitudinal hyaline lines, the pair of which form a lanceolate shape within the valve. These hyaline lines terminate near the valve apices, where the striae are not interrupted. The striae also stop short of the valve mantle, where another hyaline line completely encircles the valve along the margins.