Ancestry: Coccolithophores -> Coccolithales
Sister taxa: Isochrysidales, Coccolithales, Zygodiscales, Syracosphaerales, Coccolith families inc sed, Mesozoic Survivors, Holococcoliths, Braarudosphaerales, Discoasterales, Nannolith families inc sed, hidden,

Short diagnosis: Mostly placolith heterococcoliths, with V-unit forming the distal shield; R-unit the proximal shield.

Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Liths with R-unit extending from proximal shield to form upper/inner tube-cyle. Mostly elliptical

Liths with R-unit confined to proximal shield, mostly circular

Neritic. Coccosphere large, monomorphic with many small coccoliths. Coccoliths muroliths with open central-area; proximal and distal flanges variably developed.

Neritic; coccoliths are narrow-rimmed placoliths with obviously interlocking V and R units, open central areas


Citation: Coccolithales Schwarz, 1932
Rank: Order
Notes & discussion: The Family Coccolithaceae has often been used for all placoliths not placed in the Noelaerhabdaceae (e.g. Jordan & Kleijne 1994; Jordan & Green 1994). Young & Bown (1997) noted that two major structural types occurred in this group and divided it into two families, the Coccolithaceae and Calcidiscaceae, which they then included in their revised order Coccosphaerales. Following Jordan et al. (2004), the correct name for this order is Coccolithales. The Family Pleurochrysidaceae was also tentatively included in this order on the grounds of coccolith structure. This grouping has subsequently been supported by molecular genetic studies (Edvardsen et al. 2000; Fujiwara et al. 2001; Sáez et al. 2003, 2004) and further studies of the structure of Pleurochrysis coccoliths (Marsh 1999). In addition, the Hymenomonadaceae were included by Young et al. (2003), since numerous cytological and life-cycle characters indicate that they are closely related to the Pleurochrysidaceae (e.g. Gayral & Fresnel 1971; Gayral & Fresnel 1983; Fresnel & Billard 1991; Fresnel & Probert subm.), even though their coccolith structure is not obviously similar. This placement is also supported by molecular genetics (Sáez et al. 2004).

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

Short diagnosis: Mostly placolith heterococcoliths, with V-unit forming the distal shield; R-unit the proximal shield.

Morphology remarks: Coccoliths: The Coccolithaceae, Calcidiscaceae and Pleurochrysidaceae all form placolith coccoliths, i.e. coccoliths formed of two shields separated by a tube. Common structural features are:
1. Growth occurs downward as well as upward from the proto-coccolith ring, which consequently becomes embedded within the rim. Hence, on intact specimens, there is no obvious belt of alternating V- and R-elements, but such a belt is seen on specimens where the proximal shield has been partially detached (Young et al. 2004).
2. The V-units form the distal shield and most of the tube whilst the R-units form the proximal shield and in some cases part of the tube. In consequence the distal shield is dark in cross-polarised light whilst the proximal shield is bright.
Coccospheres: Monomorphic, this applies even to the motile genera of the Pleurochrysidaceae and Hymenomonadaceae, and to the known holococcolith stages of the Coccolithaceae and Calcidiscaceae.

Biology & life-cycles: Heteromorphic life-cycles have been documented from culture studies of the Coccolithaceae, Pleurochrysidaceae and Hymenomonadaceae and inferred from observations of combination coccospheres of Calcidiscaceae (Parke & Adams 1960; Rowson et al. 1986; Fresnel & Billard 1991; Kleijne 1991; Fresnel 1994; Cortes 2000; Renaud & Klaas 2001; Geisen et al. 2002; Billard & Inouye 2004; Houdan et al. 2004). In the Coccolithaceae and Calcidiscaceae, non-motile diploid heterococcolith-bearing stages alternate with motile haploid holococcolith-bearing stages. In the Pleurochrysidaceae and Hymenomonadaceae, motile diploid heterococcolith-bearing stages alternate with motile and benthic haploid non-calcifying stages.

Search data:
TagsLITHS: placolith, circular, elliptical,
CSPH: spherical, monomorphic, V-UNITS: distal shield, R-UNITS: prox shield, DETAILS: ca_disjunct,
MetricsLith size: 1.5->25µm;
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): within Danian Stage (61.61-66.04Ma, base in Danian stage). Data source: Total of range of species in this database

Plot of occurrence data:


Billard, C. & Inouye, I., (2004). What's new in coccolithophore biology ? In: Thierstein, H.R. and Young, J.R. (Editors), Coccolithophores - From molecular processes to global impact. Springer, pp. 1-30.

Cortés, M.Y., (2000). Further evidence for the heterococcolith-holococcolith combination Calcidiscus leptoporus-Crystallolithus rigidus. Marine Micropaleontology, 39(1-4): 35-37.

Edvardsen, B.; Eikrem, W.; Green, J.C.; Andersen, R.A.; Moon-Van Der Staay, S.Y. & Medlin, L.K., (2000). Phylogenetic reconstructions of the Haptophyta inferred from 18S ribosomal DNA sequences and available morphological data. Phycologia, 39: 19-35.

Fresnel, J. & Billard, C., (1991). Pleurochrysis placolithoides sp. nov. (Prymnesiophiceae), a new marine coccolithophorid with remarks on the status of cricolith-bearing species. British Phycological Journal, 26: 67-80.

Fresnel, J. & Probert, I., (2005). The ultrastructure and life cycle of the coastal coccolithophorid Ochrosphaera neapolitana (Prymnesiophyceae). European Journal of Phycology, 40(1): 105-122.

Fresnel, J., (1994). A heteromorphic life cycle in two coastal coccolithophorids, Hymenomonas lacuna and Hymenomonas coronata (Prymnesiophyceae). Canadian Journal of Botany, 72: 1455-1462.

Fujiwara, S.; Tsuzuki, M.; Kawachi, M.; Minaka, N. & Inouye, I., (2001). Molecular phylogeny of the haptophyta based on the rbcL gene and sequence variation in the spacer region of the RUBISCO operon. Journal of Phycology, 37: 121-129.

Gayral, P. & Fresnel, J., (1983). Description, sexualité et cycle de développment d'une nouvelle coccolithophoracée (Prymnesiophyceae): Pleurochrysis pseudoroscoffensis sp. nov. Protistologica, 19(2): 245-261.

Gayral, P. & Fresnel-Morange, J., (1971). Resultats preliminaires sur la structure et la biologie de la coccolithacee Ochrosphaera neapolitana Schussnig. Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences. Paris. Série D - Sciences Naturelles, 273: 1683-1686.

Geisen, M.; Billard, C.; Broerse, A.T.C.; Cros, L.; Probert, I. & Young, J.R., (2002). Life-cycle associations involving pairs of holococcolithophorid species: intraspecific variation or cryptic speciation? European Journal of Phycology, 37: 531-550.

Houdan, A.; Billard, C.; Marie, D.; Not, F.; Sáez, A.G.; Young, J.R. & Probert, I., (2004). Flow cytometric analysis of relative ploidy levels in holococcolithophore-heterococcolithophore (Haptophyta) life cycles. Systematics and Biodiversity, 1(4): 453-465.

Jordan, R.W. & Green, J.C., (1994). A check-list of the extant haptophyta of the world. Journal of the Marine Biological Association of the United Kingdom, 74: 149-174.

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

Jordan, R.W.; Cros, L. & Young, J.R., (2004). A revised classification scheme for living Haptophytes. Micropaleontology, 50(supplement 1): 55-79.

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

Marsh, M.E., (1999). Coccolith crystals of Pleurochrysis carterae: Crystallographic faces, organisation and development. Protoplasma, 207: 54-66.

Parke, M. & Adams, I., (1960). The motile (Crystallolithus hyalinus Gaarder & Markali) and non-motile phases in the life history of Coccolithus pelagicus (Wallich) Schiller. Journal of the Marine Biological Association of the United Kingdom, 39: 263-274.

Renaud, S. & Klaas, C., (2001). Seasonal variations in the morphology of the coccolithophore Calcidiscus leptoporus off Bermuda (N. Atlantic). Journal of Plankton Research, 23(8): 779-795.

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.

Schwarz, E., (1932). Beiträge zur Entwicklungsgeschichte der Protophyten. IX. Der Formwechsel von Ochrosphaera neapolitana. Archiv für Protistenkunde, 77: 434-462.

Sáez, A.G.; Probert, I.; Geisen, M.; Quinn, P.; Young, J.R. & Medlin, L.K., (2003). Pseudo-cryptic speciation in coccolithophores. Proceedings of the National Academy of Science of the United States of America, 100(12): 7163-7168.

Sáez, A.G.; Probert, I.; Young, J.R.; Edvardsen, B.; Wenche, E. & Medlin, L.K., (2004). A review of the phylogeny of the Haptophyta. In: Thierstein, H.R. and Young, J.R. (Editors), Coccolithophores - from molecular processes to global impact. Springer, pp. 251-270.

Young, J.R. & Bown, P.R., (1997). Cenozoic calcareous nannoplankton classification. Journal of Nannoplankton Research, 19(1): 36-47.

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.

Young, J.R.; Henriksen, K. & Probert, I., (2004). Structure and morphogenesis of the coccoliths of the CODENET species. In: Thierstein, H.R. and Young, J.R. (Editors), Coccolithophores - From molecular processes to global impact. Springer, pp. 191-216.


Coccolithales compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 26-9-2017

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