Syracosphaeraceae


Ancestry: Coccolithophores -> Syracosphaerales -> Syracosphaeraceae
Sister taxa: Calciosoleniaceae, Rhabdosphaeraceae, Syracosphaeraceae,

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


Daughter taxa (blue => in age window 0-300Ma) 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.

BCs muroliths with imbricate wall, bipartite axial structure

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

Taxonomy:

Citation: Syracosphaeraceae Lohmann, 1902
Rank: Family
Notes & 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.

Farinacci & Howe catalog pages:

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


Morphology remarks: 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.

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): 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:

References:

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

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

Cros, L.; Kleijne, A.; Zeltner, A.; Billard, C. & Young, J.R., (2000). New examples of holococcolith-heterococcolith combination coccospheres and their implications for coccolithophorid biology. Marine Micropaleontology, 39(1-4): 1-34.

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

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.

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

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

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

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


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Syracosphaeraceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 21-8-2017

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