Nannotax3 - ntax_cenozoic - Syracosphaera exigua

Syracosphaera exigua

Classification: ntax_cenozoic -> Syracosphaerales -> Syracosphaeraceae -> Syracosphaera -> SY molischii gp -> rotula type -> Syracosphaera exigua
Sister taxa: S. rotula, S. exigua, S. ampliora


Citation: Syracosphaera exigua Okada & McIntyre, 1977
Rank: species

Distinguishing features:
Parent taxon (rotula type): XCs wheel-like, with radial laths well-separated, spoke-like. BCs and XCs both show distinct chirality. CFCs not differentiated.
This taxon: BCs with node-ridge ornament; XCs ornamented elliptical discs can cover coccosphere

Farinacci & Howe catalog pages: S. exigua *


BCs - distal flange narrow, ornamented with nodes on inner margin, sutures clear and show distinct sinistral obliquity; radila laths well-separated; axial structure - irregular central ridge formed by limited upgrowth from laths. (NB Heimdal & Gaarder 1980 illustrate very different BCs as S. exigua - but these are S. dilatata or S. didyma).
XCs - elliptical, slightly asymmetric, vaulted; rim narrow; lath cycle stubby or absent; central field of a few irregular plates with ridge-like sutures. Can form a complete exotheca.

Coccospheres 7-12 µm; BCs 2-4 µm.

Search data:
TagsLITHS: murolith, placolith, SHAPE: elliptical, CA: ca_disjunct, grill, plate,
CSPH: equant, XC, CROSS-POLARS: R-prominent, T-prominent,
MetricsLith size: 1.5->3µm; Coccosphere size: 7->10µm; Liths per sphere: 35->55
Data source notes: csph & lith length (BCs) from OD & illustrated specimens; lith numbers from Yang & Wei 2003, range of estimates
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): Extant. Data source: present in the plankton (Young et al. 2003)
First occurrence (base): within No known fossil record modern (0.00-0.00Ma, base in "Holocene" stage). Data source: [JRY rough estimate]

Plot of occurrence data:


Konno, S. & Jordan, R. W. (2006). Lagoon coccolithophorids from the Republic of Palau, NW Equatorial Pacific. Journal of Nannoplankton Research. 28(2): 95-110. gs O

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

Winter, A., Reiss, Z. & Luz, B. (1979). Distribution of living coccolithophore assemblages in the Gulf of Elat ('Aqaba). Marine Micropaleontology. 4: 197-223. gs

Young, J. R., Geisen, M., Cros, L., Kleijne, A., Probert, I. & Ostergaard, J. B. (2003). A guide to extant coccolithophore taxonomy. Journal of Nannoplankton Research, Special Issue. 1: 1-132. gs V O


Syracosphaera exigua compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-8-2022

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Short stable page link: Go to to create a permanent copy of this page - citation notes

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