Nannotax3 - ntax_mesozoic - Radiolithus orbiculatus

Radiolithus orbiculatus


Classification: ntax_mesozoic -> Braarudosphaerales -> Polycyclolithaceae -> Radiolithus -> Radiolithus orbiculatus
Sister taxa: R. laingii, R. hollandicus, R. orbiculatus, R. planus, R. undosus, R. sp.

Distinguishing features:
Parent taxon (Radiolithus): Near circular to stellate eprolithids with relatively narrow wall formed from 9-16 brick-like, wall-cycle elements surrounding a wide central area spanned by an amedian diaphragm. The wall is usually lower than those seen in Eprolithus.
This taxon: Radiolithus with 9 wall-elements and high wall.


Taxonomy:

Citation: Radiolithus orbiculatus (Forchheimer, 1972) Varol, 1992
Rank: Species
Basionym: Polycyclolithus orbiculatus Forchheimer, 1972

Farinacci & Howe catalog pages: P. orbiculatus *

Distinguishing features:
Parent taxon (Radiolithus): Near circular to stellate eprolithids with relatively narrow wall formed from 9-16 brick-like, wall-cycle elements surrounding a wide central area spanned by an amedian diaphragm. The wall is usually lower than those seen in Eprolithus.
This taxon: Radiolithus with 9 wall-elements and high wall.


Morphology:

May be a variant of Eprolithus floralis.

Size:

Search data:
LITHS: nannolith-radiate, circular, cylindrical, CA: vacant, closed, CROSS-POLARS: T-prominent,
Lith size: 4->8µm; Segments: 9->9;
Data source notes: illustrated specimens
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within Turonian Stage (89.77-93.90Ma, top in Turonian stage). Data source: PRB nannotax entry
First occurrence (base): within Aptian Stage (112.95-126.30Ma, base in Aptian stage). Data source: PRB nannotax entry

Plot of occurrence data:

References:

Bown, P. R. (2001). Calcareous nannofossils of the Gault, Upper Greensand and Glauconitic Marl (Middle Albian-Lower Cenomanian) from the BGS Selborne boreholes, Hampshire. Proceedings of the Geologists' Association. 112: 223-236. gs

Crux, J. A. (1980). A biostratigraphical study of Upper Cretaceous nannofossils from South-east England and North France. PhD thesis, University College London. -. gs

Forchheimer, S. (1972). Scanning electron microscope studies of Cretaceous coccoliths from the Köpingsberg Borehole No. 1, SE Sweden. Sveriges Geologiska Undersökning, Series C. #668, 65: 1-141. gs O

Gale, A. S. et al. (2011). The uppermost Middle and Upper Albian succession at the Col de Palluel, Hautes-Alpes, France: An integrated study (ammonites, inoceramid bivalves, planktonic foraminifera, nannofossils, geochemistry, stable oxygen and carbon isotopes, cyclostratigraphy). Cretaceous Research. 32: 59-130. gs

Kennedy, W. J. et al. (2000). Integrated stratigraphy across the Aptian-Albian boundary in the Marnes Bleues, at the Col de Pre _-Guittard, Arnayon (Drome), and at Tartonne (Alpes-de-Haute-Provence), France: a candidate Global Boundary Stratotype Section and Boundary Point for the base of the Albian Stage. Cretaceous Research. 21: 591-720. gs

Püttmann, T. & Mutterlose, J. (2019). Calcareous nannofossils from a Late Cretaceous nearshore setting. Journal of Nannoplankton Research. S4: 81-88. gs V O

Varol, O. (1992b). Taxonomic revision of the Polycyclolithaceae and its contribution to Cretaceous biostratigraphy. Newsletters on Stratigraphy. 27(93-127): -. gs


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Radiolithus orbiculatus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 25-9-2022

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10979 Go to Archive.is to create a permanent copy of this page - citation notes



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