Classification: ntax_cenozoic -> Syracosphaerales -> Syracosphaeraceae
Sister taxa: Calciosoleniaceae, Rhabdosphaeraceae, Syracosphaeraceae

Daughter taxa (time control age-window is: 0-800Ma)Granddaughter taxa
Coccospheres usually dithecate. Exothecal coccoliths (XCs) highly variable. Endothecal coccoliths are muroliths with 1, 2 or 3 flanges, the forms with 2 flanges are often placolith-like.

Circum-flagellar coccoliths modified into elongate spines, supported by whorl coccoliths

Coccosphere with apical appendages formed from string of three highly-modified coccoliths, supported by whorl coccoliths

Appendages formed from strings of highly modified antapical coccoliths, without whorl coccoliths


Citation: Syracosphaeraceae Lohmann, 1902
Rank: Family
Taxonomic discussion: These coccoliths are typically delicate and only rarely preserved. The recent tendency, following Jordan & Young (1990), has been to include most species forms in the single genus Syracosphaera. The main exception is a set of genera with highly modified circum-flagellar and/or antapical coccoliths forming appendages, instead of exothecal coccoliths.
Key references: Okada & McIntyre (1977) - many new spp.; Gaarder & Heimdal (1977) - detailed descriptions of several species; Kleijne (1993) - illustration and notes on most spp. and many undescribed forms; Cros (2000) - analysis of exothecal coccoliths; Cros et al (2000) - holococcolith-heterococcolith combinations; Cros & Fortuño (2002) - detailed description of most species.

Distinguishing features: BCs muroliths or placoliths with radial laths and axial structure, ofen with higlhy modified exothecal coccoliths

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

Morphology: Cells motile, coccospheres typically elaborate, often showing dithecatism (development of distinct inner and outer layers of coccoliths) and/or modified polar coccoliths. The endothecal (inner layer) coccoliths are normally relatively conservative in form, typically muroliths with a well-developed central-area lath-cycle and variable inner central-area (coccoliths with this structure have been termed caneoliths). Exothecal coccoliths are much more variable, including planolith, murolith and dome-shaped forms (the planoliths have been termed cyrtoliths).

Biology & life-cycles: Inouye & Pienaar (1988) give detailed description of S. pulchra cytology and coccolith structure. Coronosphaera mediterranea and several species of Syracosphaera are known to have a holococcolith producing life-cycle stage.

Search data:
MetricsLith size: 0->0µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: The fossil record of the family is poor but extends back into the Paleogene; fossil specimens are normally assigned to Syracosphaera.
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): in lower part of Danian Stage (28% up, 64.8Ma, in Danian stage). Data source: Total of range of species in this database

Plot of occurrence data:


Cros, L. & Fortuño, J. -M. (2002). Atlas of northwestern Mediterranean coccolithophores. Scientia Marina. 66: 1-186. gs V O

Cros, L. (2000). Variety of exothecal coccoliths of Syracosphaera. Journal of Nannoplankton Research. 22(1): 41-51. gs V O

Cros, L., Kleijne, A., Zeltner, A., Billard, C. & Young, J. R. (2000b). New examples of holococcolith-heterococcolith combination coccospheres and their implications for coccolithophorid biology. In, Young, J. R., Thierstein, H. R. & Winter, A. (eds) Nannoplankton ecology and palaeocology, Proceedings of the INA7 conference, Puerto Rico, February 2002. Marine Micropaleontology. 39(1-4): 1-34. gs

Gaarder, K. R. & Heimdal, B. R. (1977). A revision of the genus Syracosphaera Lohmann (Coccolithineae). “Meteor” Forschungsergebnisse, Reihe D, Biologie. 24: 54-71. gs

Inouye, I. & Pienaar, R. N. (1988). Light and electron microscope observations of the type species of Syracosphaera, S. pulchra (Prymnesiophyceae). British Phycological Journal. 23: 205-217. gs V O

Jordan, R. W. & Young, J. R. (1990). Proposed changes to the classification system of living Coccolithophorids. INA Newsletter. 12(1): 15-18. gs V O

Kleijne, A. (1993b). Morphology, Taxonomy and distribution of extant coccolithophorids (Calcareous nannoplankton). Drukkerij FEBO B.V., Katwijk. 1-321. gs

Lohmann, H. (1902). Die Coccolithophoridae, eine Monographie der Coccolithen bildenden Flagellaten, zugleich ein Beitrag zur Kenntnis des Mittelmeerauftriebs. Archiv für Protistenkunde. 1: 89-165. gs V O

Okada, H. & McIntyre, A. (1977). Modern coccolithophores of the Pacific and North Atlantic Oceans. Micropaleontology. 23(1): 1-55. gs


Syracosphaeraceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 13-6-2021

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