Helicosphaera seminulum recta Haq, 1966
Coccolith has a helical flange, proximal plate and asymmetrical blanket ( Type II, Helicosphaerella recta type), which is birefringent under polarized light and partly covers the distal surface of the flange.
Blanket Type of Helicosphaerella: Asymmetrical blanket does not cover the entire distal surface of the flange (Type II, Helicosphaera recta type blanket).
Bar: a structure spanning the central opening
The orientation of the bar:
Aubry, M. -P., Bord, D., 2009. Reshuffling the cards in the photic zone at the Eocene/Oligocene boundary. In: Koeberl, C., Montanari, A. (eds), The Late Eocene Earth-Hothouse, Icehouse, and Impacts. Geological Society of America, Special Papers 452, 279-301.