Nannotax3 - ntax_mesozoic - Rhagodiscaceae

Rhagodiscaceae


Classification: ntax_mesozoic -> Eiffellithales -> Rhagodiscaceae
Sister taxa: Chiastozygaceae, Eiffellithaceae, Rhagodiscaceae

Distinguishing features:
Parent taxon (Eiffellithales): Murolith coccoliths with an upper/outer cycle of clockwise-imbricate V-units and a lower/inner cycle of R-units. 


This taxon: Eiffelithales with V-units forming most of rim (R-units typically thin plates on proximal surface, so LM images are typically unicyclic. Central-areas typically filled by a plate of granular calcite. The central structure may be spine-bearing, perforate or massive.


Daughter taxa (time control age-window is: 0-800Ma)Granddaughter taxa
Percivalia
Loxolith coccoliths with narrow outer cycle and wide central area filled with a granular plate or bridge, multiple concentric cycles seen on proximal face.

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.

Central area filled by mass of small elements
Calcicalathina
Muroliths (loxolith type) with high, narrow rim and wide central-area filled by a large, domed, granular mass.
C. alta
C. clipeus
C. erbae
C. oblongata
C. sp.

Zebrashapka
Solid, truncated-cone-shaped coccolith (possibly a holococcolith), with distinct outer rim and banded core.
Z. vanhintei
Z. sp.

Taxonomy:

Citation: Rhagodiscaceae Hay, 1977
Rank: Family
Type species: Rhagodiscus Reinhardt, 1967.

Farinacci & Howe catalog pages: Rhagodiscaceae [no catalog entry yet]

Distinguishing features:
Parent taxon (Eiffellithales): Murolith coccoliths with an upper/outer cycle of clockwise-imbricate V-units and a lower/inner cycle of R-units. 


This taxon: Eiffelithales with V-units forming most of rim (R-units typically thin plates on proximal surface, so LM images are typically unicyclic. Central-areas typically filled by a plate of granular calcite. The central structure may be spine-bearing, perforate or massive.

Search data:
TagsLITHS: murolith,
MetricsLith size: 0->0┬Ám;
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 Maastrichtian Stage (100% up, 66Ma, in Danian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Tithonian Stage (0% up, 152.1Ma, in Kimmeridgian 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

Hay, W. W. (1977). Calcareous nannofossils. In, Ramsay, A. T. S. (ed.) Oceanic Micropalaentology. Academic Press, London 1055-1200. gs


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Rhagodiscaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-10-2021

Taxon Search:
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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=11011 Go to Archive.is to create a permanent copy of this page - citation notes



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