|Daughter taxa (time control age-window is: 0-800Ma)|
Small, elliptical, with weakly imbricate rim elements, no flanges, robust lath cycle
Small Syracosphaera with moderately flaring wall, lacking flanges, wall elements show distinct clockwise imbrication, central area with single cycle of robust laths.
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
Sub-circular with narrow rim but bright central lath cycle, thickening to form central mound
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.
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
Narrow rimmed coccolith with figure-of-eight outline (indentations on each side).
Small elliptical coccolith with birefringent inner cycle and non-birefringent outer cycle.
Very small (~2 µm) elliptical; rim thick, formed of elements showing a dextral obliquity; central area with distinct radial lath cycle and central boss
Medium sized, with narrow bicyclic rim (bright inner cycle, dark outer cycle) and wide central area.
|Syraco sp. fossil|
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)
|Metrics||Lith size: 0->0µm;|
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:
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