Nannotax3 - ntax_cenozoic - Syracosphaeraceae Nannotax3 - ntax_cenozoic - Syracosphaeraceae


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.
SY pulchra gp
SY molischii gp
SY nodosa gp
SY mediterranea group
Syraco - fossil
Syracosphaera sp.

Circum-flagellar coccoliths modified into elongate spines, supported by whorl coccoliths
Calciopappus rigidus
Calciopappus caudatus
Calciopappus curvus
Calciopappus sp.

Coccosphere with apical appendages formed from string of three highly-modified coccoliths, supported by whorl coccoliths
Michaelsarsia adriaticus
Michaelsarsia elegans
Michaelsarsia sp.

Appendages formed from strings of highly modified antapical coccoliths, without whorl coccoliths
Ophiaster macrospinus
Ophiaster formosus
Ophiaster hydroideus
Ophiaster reductus
Ophiaster minimus
Ophiaster formosus var. inversus
Ophiaster sp.


Citation: Syracosphaeraceae Lohmann, 1902
taxonomic 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:
Parent taxon (Syracosphaerales): 2N: Coccoliths with radial lath cycle of T-units, and disjunct, often complex, axial structure, coccospheres often polymorphic, usually motile
N: Form holococcoliths, highly variable

This taxon: 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]


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:
Lith 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 ranges of the species in this database
First occurrence (base): within NP3 zone (63.25-64.81Ma, base in Danian stage). Data source: Total of ranges 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

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

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 1998. 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. 24: 54-71. gs O

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

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

Kleijne, A. (1993b). Morphology, Taxonomy and distribution of extant coccolithophorids (Calcareous nannoplankton). PhD Thesis, Vrije Universiteit Amsterdam. 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 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: 16-7-2024

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