Distinguishing features:
Parent taxon (Rhagodiscus): Loxolith coccoliths with low rim and central-area filled by a granular plate which may be perforate and/or spine-bearing. In xpl the rim is unicyclic moderately bright, the central area is granular, lacking a clear extinction cross.
This taxon: Small to medium-sized (4.5–6 μm) normally elliptical; central area relatively wide with a small spine base, which is bright in XPL. The coccolith is distinctly dark in XPL.
Taxonomy:
Farinacci & Howe catalog pages: R. sicutclipeus *
Distinguishing features:
Parent taxon (Rhagodiscus): Loxolith coccoliths with low rim and central-area filled by a granular plate which may be perforate and/or spine-bearing. In xpl the rim is unicyclic moderately bright, the central area is granular, lacking a clear extinction cross.
This taxon: Small to medium-sized (4.5–6 μm) normally elliptical; central area relatively wide with a small spine base, which is bright in XPL. The coccolith is distinctly dark in XPL.
Morphology:
LITHS: murolith, elliptical, CA: closed, plate, process, CROSS-POLARS: rim-unicyclic, |
Lith size: 4.5->6µm; Data source notes: Aguado et al. 2022 |
Geological Range:
Last occurrence (top): within NC7a subzone (118.27-119.40Ma, top in Aptian stage). Data source: Aguado et al. 2022
First occurrence (base): within NC5e subzone (121.52-121.83Ma, base in Barremian stage). Data source: Aguado et al. 2022
Plot of occurrence data:
Aguado, R., Company, M., O'Dogherty, L., Sandoval, J. & Martinez, M. (2022). New insights into the Barremian–lower Aptian calcareous nannofossils of the Mediterranean Tethys: Chronostratigraphic and paleobiogeographic implications. Marine Micropaleontology. 173: 1-24. gs References:
Rhagodiscus sicutclipeus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 10-12-2024
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=11412 Go to Archive.is to create a permanent copy of this page - citation notes |
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