Calculites proscissus


Classification: Mesozoic -> Holococcoliths -> Common genera -> Calculites -> Calculites proscissus
Sister taxa: C. favosus, C. anfractus, C. axosuturalis, C. obscurus, C. ovalis, C. rosalyniae, C. additus, C. cenomanicus, C. cyclops, C. juliae, C. maghredaswampensis, C. paulus, C. percernis, C. proscissus, C. turonicus, C. sarstedtensis, C. suturus, C. sp.,

Distinguishing features: Small (holotype 4µm) species with a long, narrow central perforation.


Taxonomy:

Citation: Calculites proscissus Lees, 2007
Rank: Species

Farinacci & Howe catalog pages: C. proscissus *

Distinguishing features: Small (holotype 4µm) species with a long, narrow central perforation.


Morphology remarks: "A small species of Calculites with an elongated, very narrow central perforation (or slit). At 0 ̊ in XPL, the extinction lines are aligned with the polarising directions. On rotation, the extinction lines join with the central slit to form an H-shape. Differentiation: The central slit distinguishes this from other Calculites species." [Lees 2007]

Size: Holotype dimensions: L = 4.18μm, W = 2.86μm.

Search data:
TagsLITHS: holococcolith, elliptical, CA: ca_conjunct, vacant, CROSS-POLARS: rim-unicyclic, R-prominent,
MetricsLith size: 3->5µm;
Data source notes: holotype +/-1µm
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within Early Turonian Substage (92.90-93.90Ma, top in Turonian stage). Data source: Lees 2007 (original description)
First occurrence (base): within Early Turonian Substage (92.90-93.90Ma, base in Turonian stage). Data source: Lees 2007 (original description)

Plot of occurrence data:

References:

Lees, J. A. (2007). New and rarely reported calcareous nannofossils from the Late Cretaceous of coastal Tanzania: outcrop samples and Tanzania Drilling Project Sites 5, 9 and 15. Journal of Nannoplankton Research. 29(1): 39-65. gs V O


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Calculites proscissus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 29-9-2020

Taxon Search:
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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10176 Go to Archive.is to create a permanent copy of this page - citation notes



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