Nannotax Enabling nannofossil research

Coccoliths with helical flange, sub-groups can be recognised based on presence/absence of a disjunct bar, bar orientation, flange shape, etc. (see e.g. Theodoridis 1984, Perch-Nielsen 1985b, Aubry 1990, Young 1998).

TYPE: Helicosphaera carteri

SYNONYM: Helicopontosphaera

Neogene species have been classified by Young (1998) into the following groups:

• Helicosphaera carteri group
• Helicosphaera ampliaperta group - with open central area
• Helicosphaera recta group - with inversely oriented bar and flange abruptly terminated
• Helicosphaera walbersdorfensis group - small, with flange extending unusally far round coccolith