Nannotax3 - ntax_mesozoic - Gaarderella

Gaarderella


Classification: ntax_mesozoic -> Podorhabdales -> Biscutaceae -> Gaarderella
Sister taxa: Biscutum, Discorhabdus, Similiscutum ⟩⟨ Boletuvelum, Chiastella, Crucibiscutum, Gaarderella, Gephyrobiscutum, Helicorhabdus, Jimenezberrocosoia, Seribiscutum, Sollasites

Distinguishing features:
Parent taxon (Biscutaceae): Regular placoliths; rim broad, central area relatively narrow, with variable central structures.
The distal shield is formed from V-units and the proximal shield and tube cycle are formed from R-units.

This taxon: Elliptical, large with broad shields; central area wide, spanned by a granular plate.


Daughter taxa (time control age-window is: 0-800Ma)
Gaarderella granulifera
Large placolith with broad shields and wide central area spanned by a granular central-area plate.
Gaarderella sp.
Specimens not identified to species level

Taxonomy:

Citation: Gaarderella Black, 1973
Rank: Genus
Type species: Gaarderella granulifera Black, 1973.

Farinacci & Howe catalog pages: Gaarderella *

Distinguishing features:
Parent taxon (Biscutaceae): Regular placoliths; rim broad, central area relatively narrow, with variable central structures.
The distal shield is formed from V-units and the proximal shield and tube cycle are formed from R-units.

This taxon: Elliptical, large with broad shields; central area wide, spanned by a granular plate.


Morphology:

The nature of the rim is uncertain because the type images are all proximal views, but they appear to by Sollasites-like. The use of the name for LM images is rather variable. Rarely reported.

Size:

Search data:
TagsLITHS: placolith, elliptical, CA: plate, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
MetricsLith size: 8->12µm;
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 Albian Stage (100% up, 100.5Ma, in Albian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Albian Stage (0% up, 113Ma, in Aptian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Black, M. (1973). British Lower Cretaceous Coccoliths. I-Gault Clay (Part 2). Palaeontographical Society Monograph. 127: 49-112. gs

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


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Gaarderella compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 6-7-2022

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10454 Go to Archive.is to create a permanent copy of this page - citation notes



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