Nannotax3 - ntax_main - Holococcoliths

Nannotax3 - ntax_main - Holococcoliths Nannotax3 - ntax_main - Holococcoliths

Holococcoliths

Classification: ntax_main -> Holococcoliths
Sister taxa: Isochrysidales, Coccolithales, Zygodiscales, Syracosphaerales, Coccolith families inc sed ⟩⟨ Holococcoliths, Braarudosphaerales, Discoasterales, Nannolith families inc sed ⟩⟨ Mesozoic nannofossils ⟩⟨ other groups, hidden

Daughter taxa (time control age-window is: 0-800Ma)		Granddaughter taxa
	tubeless Holococcoliths without a tube, flat or cap-shaped	Sphaerocalyptra Syracosphaera HOL (Anthosphaera type) fried egg monomorphic flat dimorphic flat (coccolithaceae HOLs) flat trapezoidal tubeless-minute
	convex Holococcoliths with tube, covered distally by a convex cover	Calyptrosphaera sphaeroidea HOL Syracosphaera pulchra HOL oblonga type Syracosphaera pulchra HOL pirus type Syracosphaera pulchra HOL galea type Calyptrolithina divergens Calyptrosphaera lluisae Calyptrosphaera heimdaliae Flosculosphaera Gliscolithus Calyptrosphaera radiata Calyptrosphaera sp. strain RCC1181
	bridged Holococcoliths with tube, spanned distally by a bridge	Corisphaera Helladosphaera Homozygosphaera Poritectolithus Syracosphaera anthos HOL
	flat-topped Holococcoliths with tube, covered distally by a flat cover	Helicosphaera HOL Holococcolithophora -flat S. aurisinae HOL type S. mediterranea HOL type Zygosphaera
	septate Holococcoliths with tube, open distally and subdivided internally by vertical septae	Calcidiscus leptoporus subsp. quadriperforatus HOL Scyphosphaera apsteinii HOL Pontosphaera japonica HOL Syracolithus sp. type A Syracolithus sp. type B Syracolithus bicorium
	open-tube Holococcoliths with tube, open distally (or cover recessed)	Calicasphaera Papposphaera HOL Trigonaspis
	fossil holococcoliths Holococcolith genera only known from the fossil record	Daktylethra Holodiscolithus Lanternithus Multipartis Octolithus Quadrilateris Semihololithus Varolia Youngilithus Zygrhablithus Aubrysphaera Corannulus Orthozygus Peritrachelina Unidentified fossil holococcoliths
	Unidentified extant holococcolith

Taxonomy:

Citation: Holococcoliths sensu Young et al., 2003

Taxonomic rank: informal group of families

Synonyms:

Family Calyptrosphaeraceae Boudreaux & Hay, 1969
Order Zygosphaerales Hay 1977
Order Zygrhablithales Varol 2025

Taxonomic discussion: It used to be conventional to place all holococcoliths in the Famly Calyptrosphaeraceae, however this is manifestly artificial, since it is now known that holococcoliths are formed during the haploid life-cycle stage of species belonging to numerous different families. Moreover, the type species of the Family Calyptrosphaeraceae, Calyptrosphaera oblonga, is now known to be a life-cycle phase of Syracosphaera pulchra, hence the name Calyptrosphaeraceae is a junior synonym of Syracosphaeraceae.
It is still convenient to group the holococcoliths together for identification purposes, but giving this artificial grouping a formal taxonomic name (e.g. Calyptrosphaeraceae, Zygosphaerales, Zygrhablithales) is no longer defensible.
Similarly the generic classification is increasingly anachronistic as more life cycle comobinations are discovered. We do still use traditional names but the groupings used here are based on morphology.

Distinguishing features:
Parent taxon (ntax_main):
This taxon: Haploid life-cycle stages, with liths formed of numerous rhombohedral microcrystals

Farinacci & Howe catalog pages:
Calyptrosphaeraceae, Zygosphaerales, Zygrhablithales *

Morphology:

Holococcoliths are formed of numerous, minute (ca 0.1 µm) rhombohedral calcite crystallites (Young & Henriksen 2003). They are produced during the haploid phase of the life-cycle of a wide range of coccolithophores that bear heterococcoliths in their diploid life-cycle phase.

Intracellular calcification
Holococcolith formation has long been suggested to occur outside the cell (e.g Rowson et al. 1986). However Langer et al. (2021) illustrated intracellular holococcolith formation in Coccolithus and this was confirmed by work of Ben Joseph et al. (2023) and by Meyer & Taylor (2025). Notably Meyer & Taylor (2025) showed well-formed holococcoliths inside C. leptoporus haploid cells.

Search data:

Lith size: 0->0µm;

The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: Although diverse holococcolith assemblages have been described from Cretaceous and Palaeogene assemblages, they are virtually absent from Neogene nannofloras. This is rather surprising, given that modern nannofloras include >60 holococcolithophores (see, e.g., Kleijne, 1991; Jordan & Kleijne, 1994; Young et al. 2003), but most species produce very small holococcoliths (often <2µm) with low preservation potential.
Last occurrence (top): Extant. Data source: Total of ranges of the species in this database
First occurrence (base): within Campanian Stage (72.17-83.65Ma, base in Campanian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
See also: customisable plot Parent: ntax_main

References:

Ben-Joseph, O., et al. (2023). Crystallization of coccolith calcite at different life-cycle phases exhibits distinct degrees of cellular confinement. Small Structures. 4: 1-9. gs

Boudreaux, J. E. & Hay, W. W. (1969). Calcareous nannoplankton and biostratigraphy of the late Pliocene-Pleistocene-Recent sediments in the Submarex cores. Revista Española de Micropaleontología. 1(3): 249-292. gs O

Jordan, R. W. & Kleijne, A. (1994). A classification system for living coccolithophores. In, Winter, A. & Siesser, W. G. (eds) Coccolithophores. Cambridge University Press, Cambridge 83-105. gs

Kleijne, A. (1991). Holococcolithophorids from the Indian Ocean, Red Sea, Mediterranean Sea and North Atlantic Ocean. Marine Micropaleontology. 17: 1-76. gs

Langer, G., et al. (2021). Role of silicon in the development of complex crystal shapes in coccolithophores. New Phytologist. New Phytologist. 1-13. gs

Meyer, E. M. & Taylor, A. R. (2025). A comparison of calcification mechanisms in haploid and diploid cells of the coccolithophore Calcidiscus leptoporus (Murray & Blackman 1898). Journal of Phycology. 1-19. gs

Rowson, J. D., Leadbeater, B. S. C. & Green, J. C. (1986). Calcium carbonate deposition in the motile (Crystallolithus) phase of Coccolithus pelagicus (Prymnesiophyceae). British Phycological Journal. 21: 359-370. gs

Young, J. R. & Henriksen, K. (2003). Biomineralization within vesicles: the calcite of coccoliths. Reviews in Mineralogy and Geochemistry. 54(1): 189-215. gs

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

Holococcoliths compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 21-4-2026

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=714 Go to Archive.is to create a permanent copy of this page - citation notes

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