Nannotax3 - ntax_main - convex Nannotax3 - ntax_main - convex

convex


Classification: ntax_main -> 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

Syracosphaera pulchra HOL galea type
Tube high and well-separated from cover; hexagonal mesh fabric

Calyptrolithina divergens
Tube sharply separated from cover; cover with perforations

Calyptrosphaera lluisae
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 large openings at base and an apical perforation

Flosculosphaera
Flaring tube-shaped coccoliths with distal cover - flosculoliths. Monomorphic.
Flosculosphaera calceolariopsis
Flosculosphaera sacculus

Gliscolithus
Bulb-shaped coccoliths with many openings in the bulb - gliscoliths. Monomorphic.
Gliscolithus amitakareniae

small forms only known from cultures
Calyptrosphaera radiata
Liths tubular with large openings near base and closed distal end. Coccosphere vari-monomorphic (coccolith height varies)

Calyptrosphaera sp. strain RCC1181
holococcoliths small (1-1.5 µm) with bulbous protrusion on a flat base, no openings, monomorphic

Taxonomy:

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

Distinguishing features:
Parent taxon (Holococcoliths): Haploid life-cycle stages, with liths formed of numerous rhombohedral microcrystals
This taxon: Holococcoliths with tube, covered distally by a convex cover

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

Search data:
Lith 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 ranges of the species in this database
First occurrence (base): within Quaternary Period (0.00-2.59Ma, base in Gelasian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:

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. S1: 1-132. gs


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convex compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 11-7-2025

Taxon Search:
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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=344 Go to Archive.is to create a permanent copy of this page - citation notes



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