Classification: ntax_cenozoic -> Holococcoliths -> convex
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
not elevated - height < length
Calyptrosphaera sphaeroidea HOL
Tube merges into cover; irregular crystallites

Syracosphaera pulchra HOL oblonga type
Tube merges into cover; hexagonal mesh fabric

Syracosphaera pulchra HOL pirus type
Tube and cover sharply separated; cover with openings at base

Calyptrolithina divergens
Tube sharply separated from cover; cover with perforations

Calyptrosphaera galea
Tube high and well-separated from cover; hexagonal mesh fabric

Calyptrosphaera sp. cf. heimdaliae
Low wall with domal cover, ring of small perforations at base of cover and an apical perforation

elevated - height > length
Calyptrosphaera heimdaliae
Tube and cover sharply separated; cover elevated with openings at base and apex

Calyptrosphaera radiata
Liths tubular with large openings near base and closed distal end. Coccosphere vari-monomorphic (coccolith height varies)

Flaring tube-shaped coccoliths with distal cover - flosculoliths. Monomorphic.

Bulb-shaped coccoliths - gliscoliths. Monomorphic.


Citation: Holococcoliths with convex 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 convex cover

Farinacci & Howe catalog pages: convex [no catalog entry yet]

Search data:
MetricsLith size: 0.9->3.2µm;
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


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

Taxon Search:
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Short stable page link: Go to to create a permanent copy of this page - citation notes

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