Helicosphaera acuta Theodoridis 1984
Elongated helicolith having a Type III (Helicosphaera carteri type) blanket, truncated flange termination and a central area with two inversely aligned pores.
Helicosphaera acuta differs from Helicosphaera burkei, Helicosphaera wallichii, Helicosphaera sellii and Helicosphaera inversa by having truncated flange termination and elongated shape.
Theodoridis, S., (1984): Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. - Utrecht Micropaleontological Bulletin. 32: 1-271.
DSDP Leg 47, Site 397, Contitental Slope off Cape Bojador, Spanish Sahara