Nannotax3 - ntax_mesozoic - Tubodiscus frankiae Nannotax3 - ntax_mesozoic - Tubodiscus frankiae

Tubodiscus frankiae


Classification: ntax_mesozoic -> Podorhabdales -> Tubodiscaceae -> Tubodiscus -> Tubodiscus frankiae
Sister taxa: T. bellii, T. burnettiae, T. frankiae, T. jurapelagicus, T. verenae, T. sp.

Distinguishing features:
Parent taxon (Tubodiscus): Tubodiscids with high and birefringent proximal collar cycle and wide central-area. Rim image is clearly bicyclic in XPL.
This taxon: Medium sized (5-7 µm) with relatively broad shields/relatively narrow central area; in xpl inner rim cycle significantly narrower than the outer rim cycle.


Taxonomy:

Citation: Tubodiscus frankiae Bown, 2005
taxonomic rank: Species

Farinacci & Howe catalog pages: T. frankiae *

Distinguishing features:
Parent taxon (Tubodiscus): Tubodiscids with high and birefringent proximal collar cycle and wide central-area. Rim image is clearly bicyclic in XPL.
This taxon: Medium sized (5-7 µm) with relatively broad shields/relatively narrow central area; in xpl inner rim cycle significantly narrower than the outer rim cycle.


Morphology:

Bicyclic placolith with relatively broad shields and open central area. In LM XPL the two cycles have contrasting width and birefringence, the inner cycle being distinctly bright and narrow, the outer being broad and dark. The central area is usually slightly broader than the shield width.

The width contrast between the two rim cycles is greater than that seen in other tubodiscids. The shield morphology and LM appearance are similar to Sollasites coccoliths, but no central area structures have been observed.

Size:
5.5-6.5 µm

Search data:
LITHS: placolith, elliptical, CA: vacant, CROSS-POLARS: R-prominent, V-prominent, rim-bicyclic,
Lith size: 5->7µm;
Data source notes: original description +/-0.5 µm
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NC4 zone (128.82-133.09Ma, top in Hauterivian stage). Data source: Bown 2005
First occurrence (base): within NC2 zone (137.41-141.12Ma, base in Berriasian stage). Data source: Bown 2005

Plot of occurrence data:

References:

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


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Tubodiscus frankiae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-12-2024

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=11275 Go to Archive.is to create a permanent copy of this page - citation notes
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