Helicosphaera theodoridisii de Kaenel & Boesiger in Boesiger et al. 2017
Helicosphaera cf. H. orientalis Theodoridis, 1984
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.
Theodoridis, S., 1984. Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. Utrecht Micropaleontological Bulletin. 32, 1-271.
Helicosphaera theodoridisii
de Kaenel & Boesiger in Boesiger et al., 2017
Middle Miocene
ODP Leg 154, Site 925C, Ceara Rise, Equatorial Atlantic Ocean