Taxonomy:
Distinguishing features:
Parent taxon (Cyclagelosphaera): Circular watznaueriacean placolith coccoliths.
This taxon: Large (8-11 µm) circular to sub-circular, with closed central area
Farinacci & Howe catalog pages: C. colorata *
Diagnosis: Large, circular to subcircular (8–11 μm) watznauaerid with an indistinct but diagnostic low central plug and overall yellow-orange birefringence. Differentiation: Distinguished from other species of Cyclagelosphaera (and Watznaueria) by its large size, yellow-orange birefringence colours, and unusual central plug structure. [Bown et al 2023]
Morphology:
NB Most specimens have distinctly elliptical central areas and resemble a large W. barnesiae with a wide rim, but, although W.barnesiae is very abundant in the Cretaceous, it is rarely larger than about 9µm (see Gollain et al 2019) [my interpretation - JRY 2024]
Ecology & Biogeography
LITHS: placolith, elliptical, circular, CA: closed, CSPH: monomorphic, CROSS-POLARS: R-prominent, |
Lith size: 8->11µm; Data source notes: Bown et al. 2023 |
Geological Range:
Notes: This species has a short stratigraphic range in the Danian (Zone NP1–2; +112 to +843 kyr after the K/Pg boundary) and is likely a descendant of Cyclagelosphaera reinhardtii. [Bown et al. 2023]
Last occurrence (top): within NP2 zone (64.81-65.47Ma, top in Danian stage). Data source: Bown et al. 2023
First occurrence (base): within NP1 zone (65.47-66.04Ma, base in Danian stage). Data source: Bown et al. 2023
Plot of occurrence data:
Bown, P. R., Kim, H. & Gibbs, S. J. (2023). Danian calcareous nannofossil evolution and taxonomy with focus on sites from the North Atlantic Ocean (IODP Expedition 342, Sites U1403 and U1407). Journal of Nannoplankton Research. 41(2): 110-157. gs O Gollain, B., Mattioli, E., Kenjo, S., Bartolini, A. & Reboulet, S. (2019). Size patterns of the coccolith Watznaueria barnesiae in the lower Cretaceous: Biotic versus abiotic forcing. Marine Micropaleontology. 152: 1-11. gsReferences:
Cyclagelosphaera colorata compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 5-12-2024
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1808 Go to Archive.is to create a permanent copy of this page - citation notes |
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