Helicosphaera seminulum recta Haq, 1966
Helicosphaera recta (Haq, 1966) Jafar & Martini, 1975
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.
Helicosphaera seminulum recta
Haq, 1966
Late Eocene
Tabqua, Raqqa, NW Syria [borehole]