Nannotax3 - ntax_mesozoic - Rhagodiscus sicutclipeus

Rhagodiscus sicutclipeus


Classification: ntax_mesozoic -> Eiffellithales -> Rhagodiscaceae -> Rhagodiscus -> Rhagodiscus sicutclipeus
Sister taxa: R. achlyostaurion, R. amplus, R. angustus, R. asper, R. cepekii, R. dekaenelii, R. infinitus, R. pseudoangustus, R. splendens ⟩⟨ R. adinfinitus, R. gallagheri, R. indistinctus, R. pancostii, R. plebeius, R. robustus, R. sageri, R. sicutclipeus ⟩⟨ R. eboracensis, R. hamptonii, R. reniformis, R. sp.

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:

Citation: Rhagodiscus sicutclipeus Aguado, in Aguado et al. 2022
Rank: species

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:

This species has an elliptic rim (axial ratio ~ 1.4) and central area that remain relatively dark under XPL. The central area bears a small spine base, which is seen as a bright, solid (not hollow) circle traversed by four sharp extinction gyres. The spine base is rela- tively small (~1.3 μm in diameter), remains isolated in the middle of the central area and does not reach the internal margin of the rim. [Aguado et al. 2022]

Size:

Search data:
LITHS: murolith, elliptical, CA: plate, process, closed, CROSS-POLARS: rim-unicyclic,
Lith size: 4.5->6µm;
Data source notes: Aguado et al. 2022
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NC7a subzone (122.25-123.88Ma, top in Aptian stage). Data source: Aguado et al. 2022
First occurrence (base): within NC5e subzone (126.40-127.31Ma, base in Barremian stage). Data source: Aguado et al. 2022

Plot of occurrence data:

References:

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 V O


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Rhagodiscus sicutclipeus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 7-10-2022

Taxon Search:
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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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