Nannotax3 - ntax_mesozoic - Radiolithus

Radiolithus


Classification: ntax_mesozoic -> Braarudosphaerales -> Polycyclolithaceae -> Radiolithus
Sister taxa: Eprolithus, Radiolithus, Farhania, Lithastrinus, Uniplanarius, Quadrum, Micula, Palaeomicula

Distinguishing features:
Parent taxon (Polycyclolithaceae): Nannoliths composed of two superposed wall cycles and a central-area which may be closed, open and vacant, or spanned by a diaphragm-like structure. Elements have tangential c-axis orientation.
This taxon: 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.


Daughter taxa (time control age-window is: 0-800Ma)
Radiolithus laingii
Radiolithus with 10-16 wall-elements and high wall.
Radiolithus hollandicus
Radiolithus 10-16 wall-elements and low wall
Radiolithus orbiculatus
Radiolithus with 9 wall-elements and high wall.
Radiolithus planus
Radiolithus with 9 wall-elements and low wall
Radiolithus undosus
Radiolithus 9 wall-elements, low wall and outline star-like
Radiolithus sp.
Specimens not identified to species level

Taxonomy:

Citation: Radiolithus Stover, 1966
Rank: Genus
Type species: Radiolithus planus Stover, 1966.
Synonyms: Rhombogyrus Black 1973 (type species R. caliciformis is a j synonym of R. planus)

Farinacci & Howe catalog pages: Radiolithus + * , Rhombogyrus *

Distinguishing features:
Parent taxon (Polycyclolithaceae): Nannoliths composed of two superposed wall cycles and a central-area which may be closed, open and vacant, or spanned by a diaphragm-like structure. Elements have tangential c-axis orientation.
This taxon: 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.


Morphology: Varol (1992) differentiated Radiolithus from Eprolithus based on the brick-like wall elements and amedian diaphragm, and included both high- (>4µm) and low-walled (<4µm) forms.

Search data:
TagsLITHS: nannolith-radiate, circular, cylindrical, CA: vacant, closed, CROSS-POLARS: T-prominent,
MetricsLith size: 4->8µm;
Data source notes: size range of included species
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of Turonian Stage (100% up, 89.8Ma, in Turonian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Aptian Stage (0% up, 126.3Ma, in Aptian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs

Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 132-199. gs V O

Stover, L. E. (1966). Cretaceous coccoliths and associated nannofossils from France and the Netherlands. Micropaleontology. 12(2): 133-167. gs

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 compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 29-1-2022

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10976 Go to Archive.is to create a permanent copy of this page - citation notes



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