Nannotax3 - ntax_mesozoic - Rhagodiscus gallagheri

Rhagodiscus gallagheri


Classification: ntax_mesozoic -> Eiffellithales -> Rhagodiscaceae -> Rhagodiscus -> Rhagodiscus gallagheri
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 (<5µm), elliptical Rhagodiscus with a length/width ratio of <2.5, straight or slightly convex longer sides, and a central area filled with a granular plate which supports a hollow spine base.


Taxonomy:

Citation: Rhagodiscus gallagheri Rutledge & Bown, 1996
Rank: Species
Taxonomic discussion: Like R. angustus but smaller and more elliptical. [see original description]

Farinacci & Howe catalog pages: R. gallagheri *

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 (<5µm), elliptical Rhagodiscus with a length/width ratio of <2.5, straight or slightly convex longer sides, and a central area filled with a granular plate which supports a hollow spine base.


Morphology:


Size:


Ecology & Biogeography


Biology & life-cycles

Phylogenetic relations

Search data:
LITHS: murolith, elliptical, quadrate, CA: plate, process, CROSS-POLARS: rim-unicyclic, R-prominent,
Lith size: 3.5->5µm;
Data source notes: original description & 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 Cenomanian Stage (93.90-100.50Ma, top in Cenomanian stage). Data source: Bown et al. 1998
First occurrence (base): at base of BC18 zone (0% up, 126.3Ma, in Aptian stage). Data source: Bown et al. 1998 - zonal marker

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

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

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

Kanungo, S., Bown, P. R. & Gale, A. S. (2020). Cretaceous (Albian-Turonian) calcareous nannofossil biostratigraphy of the onshore Cauvery Basin, southeastern India. Cretaceous Research. 118 [2021]: 1-22. 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

Rutledge, D. & Bown, P. R. (1996). New names for old: taxonomic clarification of some Early Cretaceous nannofossil marker-species. Journal of Nannoplankton Research. 18(2): 53-59. gs V O


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Rhagodiscus gallagheri compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 3-12-2022

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=11021 Go to Archive.is to create a permanent copy of this page - citation notes



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