Distinguishing features:
Parent taxon (Podorhabdales): Placolith (or modified placolith) coccoliths showing little or no imbrication. Typically, V-units form distal shield, R-units form proximal shield.
This taxon: Elevated placoliths, tube tall and proximal shield reduced; central-area with variable proximal cover.
The distal shield is formed from V-units and the proximal shield from R-units. Commonly observed in side view.
Daughter taxa (time control age-window is: 0-800Ma) | Granddaughter taxa | ||||
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. | Calyculus - late Jurassic Calyculus cribrum Calyculus depressus Calyculus noeliae Calyculus hommerili Calyculus serrai Calyculus absolutus Calyculus derivatus Calyculus magnus Calyculus sp. | ||||
Carinolithus Trumpet-shaped coccoliths with small, disc-like proximal shield and high, flaring distal shield. |
Taxonomy:
Farinacci & Howe catalog pages: Calyculaceae + *
Distinguishing features:
Parent taxon (Podorhabdales): Placolith (or modified placolith) coccoliths showing little or no imbrication. Typically, V-units form distal shield, R-units form proximal shield.
This taxon: Elevated placoliths, tube tall and proximal shield reduced; central-area with variable proximal cover.
The distal shield is formed from V-units and the proximal shield from R-units. Commonly observed in side view.
Search data:
: placolith, |
Lith size: 0->0µm; |
Geological Range:
Last occurrence (top): at top of Oxfordian Stage (100% up, 154.8Ma, in Oxfordian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within Late Pliensbachian Substage (184.20-188.00Ma, base in Pliensbachian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Bown, P. R. & Cooper, M. K. E. (1998). Jurassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 34-85. gs O Noël, D. (1973). Nannofossiles calcaires de sédiments jurassiques finement laminés. Bulletin du Muséum National d'Histoire Naturelle, Paris. 75 [1972]: 95-156. gs Young, J. R. & Bown, P. R. (1997). Proposals for a revised classification system for calcareous nannoplankton. Journal of Nannoplankton Research. 19(1): 15-47. gs References:
Calyculaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 14-12-2024
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10182 Go to Archive.is to create a permanent copy of this page - citation notes |
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