Nannotax3 - ntax_cenozoic - Syracosphaeraceae

Citation: Syracosphaeraceae Lohmann, 1902

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

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).

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 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

References:

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

Daughter taxa (time control age-window is: 0-800Ma)		Granddaughter taxa
	Syracosphaera 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.
	Calciopappus Circum-flagellar coccoliths modified into elongate spines, supported by whorl coccoliths	Calciopappus rigidus Calciopappus caudatus Calciopappus curvus Calciopappus sp.
	Michaelsarsia Coccosphere with apical appendages formed from string of three highly-modified coccoliths, supported by whorl coccoliths	Michaelsarsia adriaticus Michaelsarsia elegans Michaelsarsia sp.
	Ophiaster 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.