Calculites cenomanicus

Classification: Mesozoic -> Holococcoliths -> Common genera -> Calculites -> Calculites cenomanicus
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 with irregular elongate central opening


Citation: Calculites cenomanicus Lees, 2007
Rank: Species

Farinacci & Howe catalog pages: Calculites cenomanicus *

Distinguishing features: Small with irregular elongate central opening

Morphology remarks: "A small species of Calculites with an irregular-looking, elongated central perforation. At 0 ̊ in XPL, the extinction lines are aligned with the polarising directions. On rotation, the extinction lines form v-shapes at the ends of the lith that are truncated by the ends of the perforation. The central perforation appears to contain a structure (Pl.10, figs 37, 38), but this is not resolvable. Differentiation: The elongated, irregular-looking central perforation and vague central structure distinguish this from other Calculites species." [Lees 2007]

Size: Holotype dimensions: L = 4.40μm, W = 2.64μm.

Search data:
TagsLITHS: holococcolith, elliptical, hollow, CA: vacant, process, R-UNITS: R-prominent, DETAILS: ca_conjunct, rim-unicyclic,
MetricsLith size: 4->5µm;
Sources: holotype +/-0.5µm
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within Cenomanian Stage (93.90-100.50Ma, top in Cenomanian stage). Data source: Lees 2007 (original description)
First occurrence (base): within Cenomanian Stage (93.90-100.50Ma, base in Cenomanian stage). Data source: Lees 2007 (original description)

Plot of occurrence data:

  • (NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Calculites


    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 :: view :: open


    Calculites cenomanicus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 9-7-2020

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    Short stable page link: Go to to create a permanent copy of this page - citation notes

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