Helicosphaerella recta

Helicosphaera seminulum recta Haq, 1966

Sub-rectangular helicolith has an asymmetrical blanket (Type II, Helicosphaerella recta type), truncated flange termination and a central area with traverse conjunct bar with relatively small pores at both sides.

Helicosphaerella recta is distinguished from Helicosphaerella truncata (Bramlette & Wilcoxon,1967) Aubry, Liu, de Vargas, & Probert in Aubry & Bord (2009) by having smaller central pores.

Helicosphaerella recta is distinguished from Helicosphaerella robinsoniae (Bown & Dunkley Jones, 2012) Varol, n. comb. by having a conjunct bar rather than a disjunct bar.

Helicosphaerella recta was described from Upper Eocene sediments but considered to be caved in here from Oligocene to Early Miocene sediments.

Bown, P. R., Dunkley Jones, T., 2012. Calcareous nannofossils from the Paleogene equatorial Pacific (IODP Expedition 320 Sites U1331-1334). Journal of Nannoplankton Research 32(2), 3-51.

Bramlette, M. N., Wilcoxon, J. A., 1967. Middle Tertiary calcareous nannoplankton of the Cipero section, Trinidad, W.I. Tulane Studies in Geology and Paleontology 5, 93-131.

Haq, B. U., 1966. Electron microscope studies on some upper Eocene calcareous nannoplankton from Syria. Stockholm Contributions in Geology 15, 23-37.

Jafar, S. A., Martini, E., 1975, On the validity of the calcareous nannoplankton genus Helicosphaera. Senckenbergiana Lethaea 56, 381-397.