Helicosphaera compacta Bramlette & Wilcoxon, 1967
Helicosphaera disrupta de Kaenel & Bergen in Boesiger et al., 2017 is possibly reworked Helicosphaerella compacta.
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.
Boesiger, T. M., de Kaenel, E., Bergen, J. A., Browning, E., Blair, S. A. , 2017. Oligocene to Pleistocene taxonomy and stratigraphy of the genus Helicosphaera and other placolith taxa in the circum North Atlantic Basin. - Journal of Nannoplankton Research 37(2-3), 145-175.
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.
Helicosphaera compacta
Bramlette & Wilcoxon, 1967
Early Oligocene
Cipero Section, Trinidad