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

Short diagnosis: Liths with R-unit extending from proximal shield to form upper/inner tube-cyle. Mostly elliptical

Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Eliptical or circular; central area open or with simple bar or weak axial cross

Like Cruciplacolithus but coccoliths small and with large, thin, paddle-like processes.

Like Cruciplacolithus but the coccoliths are longitudinally arched and typically near parallel sided, and so appear oblong in outline

Placolith coccoliths with Coccolithus-type shields and tube, but with disjunct diagonal cross bars spanning the central area.

Rim structure like Coccolithus; perforate plate covers the central area on the distal side

Coccoliths ring-shaped without discrete shields

Placolith coccoliths with a wide central-area typically spanned by multi-element lattice-like grills or imperforate plates.

Coccolith central area spanned by disjunct axial cross that may be rotated by up to 20 degrees.

Coccolithus-like coccoliths that are typically circular and have broad upper tube elements that dominate the distal shield. The dominance of the R-unit cycle results in a bright LM XPL image that is distinct from Coccolithus.

Placolith coccoliths showing low birefringence with central area filled by 2 to 4 plates. Lacks a clearly birefringent distal tube cycle

Placolith coccoliths, typically small (c. 3 microns), with central-area spanned by a finely perforate net. The distal shield is typically bicyclic and the rim structure appears to be coccolithacean.

Rim narrow and central area spanned by an elevated bridge


Citation: Coccolithaceae Poche, 1913 emend. Young & Bown, 1997
Rank: Family

Farinacci & Howe catalog pages:

Short diagnosis: Liths with R-unit extending from proximal shield to form upper/inner tube-cyle. Mostly elliptical

Morphology remarks: Heterococcoliths are placoliths with rim structure similar to Coccolithus: V-unit forms both distal shield and lower cycle of central-area; R-unit forms both proximal shield and upper cycle of central-area. The proximal shield itself is bicyclic with distinct upper and lower layers but these are both formed from the R-unit. The central-area is often spanned by disjunct structures and these are used to define various fossil genera (see e.g. Perch-Nielsen 1985, Young & Bown 1997,Young & Henriksen 2003).

Biology & life-cycles: Modern Coccolithus pelagicus has a holococcolith stage

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:


Perch-Nielsen, K., (1985). Cenozoic calcareous nannofossils. In: Bolli, H.M., Saunders, J.B. and Perch-Nielsen, K. (Editors), Plankton Stratigraphy. Cambridge University Press, Cambridge, pp. 427-555.

Poche, F., (1913). Das System der Protozoa. Archiv für Protistenkunde, 30: 125-321.

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

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

Nannotax3 - Coccolithophores - Coccolithaceae by: Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 24-3-2017

Search term: in module

AphiaID: 178597 Nomenclatural data on WoRMS

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