Daughter taxa (time control age-window is: 0-800Ma) | ||||
Cyclagelosphaera alta Cyclagelosphaera with central-plug-forming inner tube cycle that forms a raised conical structure. | ||||
Cyclagelosphaera colorata Large (8-11 µm) circular to sub-circular, with closed central area | ||||
Cyclagelosphaera margerelii Cyclagelosphaera with closed central area. | ||||
Cyclagelosphaera reinhardtii Cyclagelosphaera with central-plug-forming inner tube cycle that is raised above shield level, forming a raised conical structure. | ||||
Cyclagelosphaera rotaclypeata Cyclagelosphaera with relatively wide central area filled with radial elements. | ||||
Cyclagelosphaera sp. Specimens which cannot be assigned to any established species |
Taxonomy:
Distinguishing features:
Parent taxon (Watznaueriaceae): Placoliths or modified placoliths with R-unit well developed, forming proximal and distal shield elements with opposite senses of imbrication; the V-unit typically forms a narrow distal cycle near the inner edge of the shield. Central-area structures are typically disjunct. Birefringent LM image, in which the V-unit cycle appears only as a thin, dark line.
This taxon: Circular watznaueriacean placolith coccoliths.
Farinacci & Howe catalog pages: Cyclagelosphaera *
Search data:
LITHS: placolith, circular, CA: ca_conjunct, CSPH: equant, monomorphic, CROSS-POLARS: R-prominent, rim-unicyclic, |
Lith size: 4->8µm; Liths per sphere: 11->13 |
Geological Range:
Notes: Cyclagelosphaera is a common genus in the Late Jurassic and Early Cretaceous, rarer in the Late Cretaceous.
Last occurrence (top): at top of NP10 zone (100% up, 54.2Ma, in Ypresian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NJ11 zone (165.71-168.69Ma, base in Bajocian 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. (1965). Sur les Coccolithes du Jurassique Européen et d'Afrique du Nord. Essai de classification des coccolithes fossiles. Éditions du Centre National de la Recherche Scientifique, Paris. 1-209. gsReferences:
Cyclagelosphaera compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 10-12-2024
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=402 Go to Archive.is to create a permanent copy of this page - citation notes |
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