Classification: Coccolithophores -> Coccolithales -> Pleurochrysidaceae
Sister taxa: Coccolithaceae, Calcidiscaceae, Hymenomonadaceae, Pleurochrysidaceae,

Daughter taxa: (blue => in age window 0-800Ma) Granddaughter taxa
Coccoliths elliptical narrow-rimmed placoliths with complex rim structure, open central area


Citation: Pleurochrysidaceae Fresnel & Billard, 1991
Rank: Family
Notes & discussion: At one time species were assigned to either Cricosphaera or Pleurochrysis on the basis of their life-cycles. Following revisions of Jordan et al. (1993) the family is now monogeneric.

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

Farinacci & Howe catalog pages: Pleurochrysidaceae

Morphology remarks: Coccoliths are formed of two cycles of tightly interlocked anvil-shaped crystal-units. V-unit forms distal shield and tube. R-unit forms proximal shield and small element on inside of tube (Marsh 1999). Central area open. Coccoliths with this structure have been termed cricoliths. Coccospheres large with numerous liths, monomorphic.

Evolution & Phylogeny: This family was included in the Coccolithales by Young & Bown (1997) since the rim structure appears to be a simplified version of that of the Coccolithaceae. This is supported by the detailed analysis of coccolith structure of Marsh (1999) and molecular genetic data, (Edvardsen et al., 2000; Fujiwara et al., 2001; Sáez et al. 2004)

Ecology & Biogeography: Neritic

Biology & life-cycles: These species are neritic and easily isolated and maintained in culture., hence taxonomy is based on cultures. Diploid phase is motile and heterococcolith-bearing, haploid phase is non-calcifying, flagellate or benthic.
Key references: Gayral & Fresnel (1983) - life-cycle; van der Wal et al. (1983) - cytology; Fresnel & Billard (1991) - species overview; Marsh (1999) - coccolith ultrastructure.

Search data:
TagsRIM: rim-narrow,
CSPH: spherical, V-UNITS: distal shield, px-tube, R-UNITS: prox shield, tube, DETAILS: isogyres oblique,
MetricsLith size: 1.5->4µm;
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 top of No known fossil record modern (100% up, 0Ma, in stage). Data source: Total of range of species in this database

Plot of occurrence data:


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. gs :: ::

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. gs :: ::

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. gs :: ::

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. gs :: ::

Jordan, R. W., Kleijne, A. & Heimdal, B. R. (1993). Proposed changes to the classification system of coccolithophorids. III. INA Newsletter. 15(1): 18-22. gs :: view :: open

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

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. & Young, J. R. (eds) Coccolithophores - from molecular processes to global impact. Springer, Berlin 251-270. gs :: view :: open

van der Wal, P., de Jong, E. W., Westbroek, P., de Bruijn, W. C. & Mulder-Stapel, A. A. (1983). Ultrastructural polysaccharide localization in calcifying and naked cells of the coccolithophorid Emiliania huxleyi. Protoplasma. 118: 157-168. gs :: ::

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


Pleurochrysidaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-7-2020

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