Nannotax3 - ntax_mesozoic - Rhagodiscus pseudoangustus Nannotax3 - ntax_mesozoic - Rhagodiscus pseudoangustus

Rhagodiscus pseudoangustus


Classification: ntax_mesozoic -> Eiffellithales -> Rhagodiscaceae -> Rhagodiscus -> Rhagodiscus pseudoangustus
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-medium, sub-rectangular with parallel sides, rounded ends and a narrow central area spanned by a large hollow spine base. The rim may be irregularly thickened. Often seen in side view.


Taxonomy:

Citation: Rhagodiscus pseudoangustus Crux, 1987
taxonomic rank: Species
Synonyms:

Farinacci & Howe catalog pages: R. pseudoangustus * , Z. pseudoangustus *

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-medium, sub-rectangular with parallel sides, rounded ends and a narrow central area spanned by a large hollow spine base. The rim may be irregularly thickened. Often seen in side view.

Search data:
LITHS: murolith, quadrate, hollow, CA: process, CROSS-POLARS: rim-unicyclic, R-prominent,
Lith size: 4->7µm;
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:
Notes: This is an Early Cretaceous species which does not overlap in range with R. angustus
Last occurrence (top): at top of BC13 zone (100% up, 125.3Ma, in Barremian stage). Data source: Bown et al. 1998 - zonal marker
First occurrence (base): within Hauterivian Stage (126.50-132.60Ma, base in Hauterivian stage). Data source: Bown et al. 1998

Plot of occurrence data:

References:

Applegate, J. L. & Bergen, J. A. (1988). Cretaceous calcareous nannofossil biostratigraphy of sediments recovered from the Galicia Margin, ODP Leg 103. Proceedings of the Ocean Drilling Program, Scientific Results. 103: 293-348. gs O

Bown, P. R. (2005c). Early to Mid-Cretaceous Calcareous Nannoplankton from the Northwest Pacific Ocean, Leg 198, Shatsky Rise. Proceedings of the Ocean Drilling Program, Scientific Results. 198: 1-82. gs 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

Covington, J. M. & Wise, S. W. (1987). Calcareous nannofossil biostratigraphy of a Lower Cretaceous deep-sea fan complex: Deep Sea Drilling Project Leg 93 Site 603, lower continental rise off Cape Hatteras. Initial Reports of the Deep Sea Drilling Project. 93: 617-660. gs O

Crux, J. A. (1987c). Six new species of calcareous nannofossils from the Lower Cretaceous strata of England and Germany. INA Newsletter. 9(1): 30-35. gs

Crux, J. A. (1989). Biostratigraphy and palaeogeographical applications of Lower Cretaceous nannofossils from north-western Europe. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications: Proceedings of the 2nd INA Conference, London 1987. British Micropalaeontological Society Publication Series . 143-211. gs

de Kaenel, E. & Bergen, J. A. (1996b). Mesozoic calcareous nannofossil biostratigraphy from sites 897, 899, and 901, Iberia Abyssal Plain: New biostratigraphic evidence. Proceedings of the Ocean Drilling Program, Scientific Results. 149: 27-59. gs O


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Rhagodiscus pseudoangustus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 17-7-2024

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