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Nannotax3 - ntax_mesozoic - Calyculus - late Jurassic Nannotax3 - ntax_mesozoic - Calyculus - late Jurassic

Calyculus - late Jurassic


Classification: ntax_mesozoic -> Podorhabdales -> Calyculaceae -> Calyculus -> Calyculus - late Jurassic
Sister taxa: C. - late Jurassic ⟩⟨ C. cribrum, C. depressus ⟩⟨ C. noeliae ⟩⟨ C. hommerili, C. serrai ⟩⟨ C. absolutus, C. derivatus, C. magnus, C. sp.

Distinguishing features:
Parent taxon (Calyculus): High, broad, flaring distal-shield composed of radial, non-imbricating elements, and a proximal-shield which is often reduced to a simple, narrow cycle of elements; central-area structures are highly variable, including numerous bars, concentric structures, nets and grills.
This taxon: Broadly elliptical, with 8-10 radial bars in central area.


Taxonomy:

Citation: Calyculus subcircularis Grun & Zweili 1980
Taxonomic rank: species
Synonyms:
Taxonomic discussion: Late Jurassic species of Calyculus have occasionally been described, under various names. There are enough good images to establish these are genuine occurences, not reworking, and the central structure seen in some of 8-10 radial bars in not know from Toarcian Calyculus. Since the taxonomy has not been clarified all images are presented together here.
The three described species appear very similar, so it probably is not useful to separate them, given this the senior synonym is Proculithus charlottei but this should be recombined into Calyculus. [my interpretation - JRY 2021]
NB The correct spelling of the name is charlottei, with one i, - see also discussion on the catalog page.

Farinacci & Howe catalog pages: C. subcircularis * , C. elongatus * , P. charlotteii *

Distinguishing features:
Parent taxon (Calyculus): High, broad, flaring distal-shield composed of radial, non-imbricating elements, and a proximal-shield which is often reduced to a simple, narrow cycle of elements; central-area structures are highly variable, including numerous bars, concentric structures, nets and grills.
This taxon: Broadly elliptical, with 8-10 radial bars in central area.

Search data:
LITHS: placolith, elliptical, CA: grill,
CSPH: equant,
Lith size: 0->0µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within Oxfordian Stage (154.78-161.50Ma, top in Oxfordian stage). Data source: Grun & Zweili 1980
First occurrence (base): within Oxfordian Stage (154.78-161.50Ma, base in Oxfordian stage). Data source: Grun & Zweili 1980

Plot of occurrence data:

References:

Grün, W. & Zweili, F. (1980). Das kalkige Nannoplankton der Dogger-Malm-Grenze im Berner Jura bei Liesberg (Schweiz). Jahrbuch der Geologischen Bundesanstalt. 123: 231-341. gs

Medd, A. W. (1979). The Upper Jurassic coccoliths from the Haddenham and Gamlingay boreholes (Cambridgeshire, England). Eclogae Geologicae Helvetiae. 72: 19-109. gs O

Zweili, F. (1989). Fossile Coccolithophoriden aus dem Weissensteingebiet. Mitteilungen / Naturforschende Gesellschaft des Kantons Solothurn. 34: 199-213. gs O


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Calyculus - late Jurassic compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 25-3-2025

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=11405 Go to Archive.is to create a permanent copy of this page - citation notes
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