Syraco - fossil

Classification: ntax_cenozoic -> Syracosphaerales -> Syracosphaeraceae -> Syracosphaera -> Syraco - fossil
Sister taxa: SY pulchra gp, SY molischii gp, SY nodosa gp, SY mediterranea group, Syraco - fossil, S. sp.

Daughter taxa (time control age-window is: 0-800Ma)
Nodosella franzii
Small, elliptical, with weakly imbricate rim elements, no flanges, robust lath cycle
Syracosphaera clathrata
Small Syracosphaera with moderately flaring wall, lacking flanges, wall elements show distinct clockwise imbrication, central area with single cycle of robust laths.
Syracosphaera croatica
small Syracosphaera with flaring rim formed of clockwise-imbricate elements, low basal cycle forms proximal flange; central area with well-spaced lath cycle; low central spine sometimes present
Syracosphaera fragilis
Sub-circular with narrow rim but bright central lath cycle, thickening to form central mound
Syracosphaera horvati
Small (ca 2µm) delicate species of Syracosphaera; narrow vertical wall; central area with two cycles of radial laths and low central spine on some specimens.
Syracosphaera monechiae
Small (3–4 µm), elliptical; rim narrow formed of sub-vertical elements with a distinct proximal flange; central-area wide spanned by a well-developed fragile lath cycle and a low central spine
Syracosphaera octiforma
Narrow rimmed coccolith with figure-of-eight outline (indentations on each side).
Syracosphaera oneillii
Small elliptical coccolith with birefringent inner cycle and non-birefringent outer cycle.
Syracosphaera raffiae
Very small (~2 µm) elliptical; rim thick, formed of elements showing a dextral obliquity; central area with distinct radial lath cycle and central boss
Syracosphaera tanzanensis
Medium sized, with narrow bicyclic rim (bright inner cycle, dark outer cycle) and wide central area.
Syraco sp. fossil


Citation: Syracosphaera - fossil species
Rank: species group
Taxonomic discussion: Syracosphaera does not have an extensive fossil record and many of the modern species are so small that have very low preservation potential and would be very difficult to identify if they were preserved. Nonetheless fossil speciemens do occur, especially in well-preserved shelf sediments. For convenience all species which have been decribed from the fossil record are grouped here.
Danian species of ?Nodosella described by Perch-Nielsen 1981 may be early Syracosphaera species

Distinguishing features: FossilSyracosphaera coccoliths

Farinacci & Howe catalog pages: Syraco - fossil [no catalog entry yet]

Morphology: Some species (S. clathrata, S. croatica),  show distinct clockwise imbrication of the elements (in contrast to anticlockwise imbrication shown by Coronosphaera)

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: Most decribed fossil Syracosphaera species are from the Late Eocene but the genus probbly was preent throughout the Cenozoic since some very similar Mesozoic forms occur. Altrntively Syracosphaera may have evolved from Calciosolenia in the Palaeogene.
Last occurrence (top): in upper part of Tortonian Stage (76% up, 8.3Ma, in Tortonian stage). 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:


Perch-Nielsen, K. (1981b). New Maastrichtian and Paleocene calcareous nannofossils from Africa, Denmark, and USA and the Atlantic, and some Paleocene lineages. Eclogae Geologicae Helvetiae. 74(3): 831-863. gs V O


Syraco - fossil compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-5-2021

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