Classification: ntax_cenozoic -> Holococcoliths -> flat-topped
Sister taxa: tubeless, convex, bridged, flat-topped, septate, open-tube, fossil holococcoliths, U. extant holococcolith

Daughter taxa (time control age-window is: 0-800Ma)Granddaughter taxa
Calyptrosphaera -flat
Monomorphic - cavate
Coccoliths with broad rim and recessed distal cover without boss

Helicosphaera HOL
Monomorphic; liths solid - formed of layers of crystallites in rhomboid array
Coccolith distal surface with central boss and varying number of depressions.

Dimorphic - liths cavate
BCs flat topped with large openings in tube and variable openings in distal surface; tiered wall fabric; low transverse ridge.
CFCs helladoliths - ridge of BCs is extended into prominent leaf, no openings in tube.

S. mediterranea HOL type
Dimorphic - usually cavate
BCs with flat distal cover with or without openings; central boss
CFCs; with irregular bridge or distal cover arched upwards

Dimorphic; liths semi-solid - formed of concentric rings of crystallites.
BCs flat topped with node or ridge on distal surface, rather than a true bridge.
CFCs similar with transverse bridge or leaf.


Citation: Holococcoliths with flat cover over the tube - informal grouping proposed by Young et al., 2003
Rank: informal group of genera

Distinguishing features: Holococcoliths with tube, covered distally by a flat cover

Farinacci & Howe catalog pages: flat-topped [no catalog entry yet]

Search data:
MetricsLith size: 1.6->3.3µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): at base of Gelasian Stage (0% up, 2.6Ma, in Gelasian stage). Data source: Total of range of species in this database

Plot of occurrence data:


Young, J. R., Geisen, M., Cros, L., Kleijne, A., Probert, I. & Ostergaard, J. B. (2003). A guide to extant coccolithophore taxonomy. Journal of Nannoplankton Research, Special Issue. 1: 1-132. gs V O


flat-topped compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 13-6-2021

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=581 Go to Archive.is to create a permanent copy of this page - citation notes

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