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: Small elliptical Calyculus; rim low & narrow; central area with axial cross and concentric lozenge.
Taxonomy:
Farinacci & Howe catalog pages: C. depressus *
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: Small elliptical Calyculus; rim low & narrow; central area with axial cross and concentric lozenge.
Size:
LITHS: placolith, elliptical, CA: concentric-ring(s), cross-axial, ca_disjunct, CROSS-POLARS: V-prominent, rim-unicyclic, |
Lith size: 3->4µm; Data source notes: holotype +/- 0.5 µm |
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 Late Pliensbachian Substage (184.20-188.00Ma, base in Pliensbachian stage). Data source: Bown, 1987 (original description)
Plot of occurrence data:
Bown, P. R. (1987a). Taxonomy, evolution, and biostratigraphy of Late Triassic-Early Jurassic calcareous nannofossils. Special Papers in Palaeontology. 38: 1-118. gsReferences:
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Calyculus depressus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 29-4-2025
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10186 Go to Archive.is to create a permanent copy of this page - citation notes |
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