Nannotax3 - ntax_mesozoic

Nannotax3 - ntax_mesozoic - Crucibiscutum Nannotax3 - ntax_mesozoic - Crucibiscutum

Crucibiscutum

Classification: ntax_mesozoic -> Podorhabdales -> Biscutaceae -> Crucibiscutum
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 with prominent, birefringent, axial cross.

Daughter taxa (time control age-window is: 0-800Ma)
				Late Cretaceous species
				Crucibiscutum hayi Medium-sized (ca 5-6 µm)Crucibiscutum with relatively wide central area, relatively narrow rim and slender-armed axial cross.
				Podorhabdus quadriperforatus
				Early Cretaceous species
				Crucibiscutum bastetanum Small (3.5-5.5 µm) with slightly rotated cross, central area narrow, tube cycle (R-units) broader than outer rim
				Crucibiscutum gracile Small (3.5-5 µm) sub-circular or broadly elliptical, central area wide, cross bars slender
				Crucibiscutum neuquenensis Medium-sized (ca 5-7 µm), broadly elliptical Crucibiscutum; central-area relatively wide, with off-axial (slightly-rotated) cross-bars.
				Crucibiscutum pinnatus Small (ca 3-5 µm)Crucibiscutum with central cross that is only weakly birefringent and does not fill the central area, delineating four perforations that are clearly visible in XPL.
				Crucibiscutum ryazanicum Small (4-5 µm) with an asymmetrical central cross.
				Crucibiscutum salebrosum Small (ca 3-5 µm) Crucibiscutum with narrow central area and birefringent cross. The central cross practically fills the narrow central area, and has the same intensity birefringence as the tube cycle (white).
				Crucibiscutum trilensis Medium-sized (ca 5-6 µm), Crucibiscutum; broadly elliptical with a relatively wide central-area .
				Crucibiscutum sp. Specimens not identified to species level

Taxonomy:

Citation: Crucibiscutum Jakubowski, 1986

Rank: Genus

Type species: Cruciplacolithus salebrosus Black, 1971, designated by Jakubowski, 1986.

Farinacci & Howe catalog pages: Crucibiscutum *

Search data:

LITHS: placolith, elliptical, CA: cross-axial, ca_disjunct, process, diagonal cross, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,

Lith size: 3->7µm;
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 Cenomanian Stage (100% up, 93.9Ma, in Cenomanian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Berriasian Stage (0% up, 145Ma, in Berriasian stage). Data source: Total of range of species in this database

Plot of occurrence data:

Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Neptune data: This is a higher taxon page so Neptune data is not plotted. See also: customisable plot Parent: Biscutaceae

References:

Black, M. (1971a). Coccoliths of the Speeton Clay and Sutterby Marl. Proceedings of the Yorkshire Geological Society. 38: 381-424. 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

Jakubowski, M. (1986). New calcareous nannofossil taxa from the Lower Cretaceous of the North Sea. INA Newsletter. 8(1): 38-42. gs V O

Crucibiscutum compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 31-3-2023

Taxon Search:

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AphiaID: not found
Short stables page link: https://mikrotax.org/Nannotax3/index.php?id=10316 Go to Archive.is to create a permanent copy of this page - citation notes

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