Description
Cells armored, elongated, with a pentagonal to pyriform shape in ventral and dorsal views, moderately dorsoventrally compressed, and with slightly convex lateral sides of the epitheca and hypotheca (Figs 2a, b, d–f, and 4a–b). The epitheca is tapering into a robust apical horn, which is slightly shorter than antapical horns (Figs 2a, e–f, and 4a–b). The first apical plate 1’ is symmetrical and orthogonal, with its proximal margins being the longest (Figs 2a–b, e, and 4a). The quadrangular 1a plate is the smallest apical intercalary plate (Figs 2h, and 4b, d). The plate 2a is asymmetrical and pentagonal, slightly shifted to the left (Figs 2d, h, and 4b, d). The pentagonal 3a plate is about triple the area of plate 1a (Figs 2d, h, and 4b, d), and the fourth precingular plate (4”) is trapeziform (Figs 2d, h, and 4b, d). The cingulum is equatorial, displaced, descending by about 0.5–0.75 cingular width (Figs 2a–b, e, and 4a), not excavated, moderately inclined relative to the equatorial plane of the cell, and bears prominent smooth cingular lists (Figs 2e–f). The broad sulcus is shallow and somewhat oblique, bordered by sulcal lists (Figs 2a, e, and 4a). The hypotheca possesses two long antapical horns, slender and slightly divergent (the right one slightly longer than the left) ending in sharp tips (Figs 2a, e–f, and 4a–c). The distance between the tips of the antapical horns is narrower than the cell’s width (Figs 2a, e–f, and 4a–b). The theca is faintly reticulated with incomplete meshes and two kinds of pore sizes (Fig. 2g). Dimensions : length 143 ± 2 µm (min. 140 µm, max. 145 µm, n = 30), width 61 ± 1 µm (min. 60 µm, max. 63 µm, n = 30), and depth 37 ± 2 µm (min. 35 µm, max. 40 µm, n = 30).