Taxonomy:
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: Large (ca 6-8 µm across), broadly elliptical Calyculus; rim elevated, broad; central area with grill
Farinacci & Howe catalog pages: I. magnum *
Search data:
LITHS: placolith, elliptical, hollow, CA: ca_disjunct, grill, CROSS-POLARS: rim-unicyclic, V-prominent, |
Lith size: 6->8µm; Data source notes: holotype +/- 1µm |
Geological Range:
Last occurrence (top): within Early Toarcian Substage (177.50-184.20Ma, top in Toarcian stage). Data source: Bown 1987 (original description)
First occurrence (base): within Early Toarcian Substage (177.50-184.20Ma, base in Toarcian stage). Data source: Bown 1987 (original description)
Plot of occurrence data:
Crux, J. A. (1984). Biostratigraphy of Early Jurassic calcareous nannofossils from southwest Germany. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 169: 160-186. gs O Goy, G. (1981). Nannofossiles calcaires des schistes carbon (Toarcien Inferieur) du Bassin de Paris. Doc. de la RCP 459, Nature et genese des facies confines, (Editions du BRGM). 1: 1-86. gs OReferences:
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Calyculus magnus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 21-5-2025
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10189 Go to Archive.is to create a permanent copy of this page - citation notes |
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