BCs conical with basal flange
BCs flatter than S. quadridentata
BCs taller, more conical than S. quadridentata
Elliptical base supports conical protrusion with a few large perforations
BCs low but sharp cones; ca. 1.5 µm long. CFCs high cones with distinct base 2 crystallites high
BCs narrow-based steep cones with sharp tip; ca. 0.8 µm long, 0.8 µm high. CFCs high cones with distinct base 2 crystallites high.
BCs with basal ring 2 crystallites high; surmounted by open cone of 3-4 robust bars; ca. 1.1 µm long. CFCs similar but with spine rising from the cone.
BCs with basal ring 1 crystallite high; surmounted by open cone of 4-6 delicate bars, with apical spine; ca. 1.7 µm long. CFCs similar but with tall spine.
BCs with curved cover with 2-3 openings; ca. 1.6 µm long. CFCs with conical spine supported by a few bars.
BCs delicate, ?domal (good specimens not seen); ca. 0.8 µm long. CFCs with long straight spine.
Elliptical base supports two arms
Specimens which cannot be assigned to established species
