Distinguishing features: Elliptical and often polygonal; rims low but broad, bicyclic; central-area spanned by one to eight bars; prominent spines protrude from the rim
Daughter taxa (time control age-window is: 0-800Ma)![]() | Granddaughter taxa | ||||
![]() | ![]() | ![]() | ![]() | Stephanolithion atmetos Narrowly elliptical, near-parallel sided, with transverse bar | |
![]() | ![]() | ![]() | Stephanolithion bigotii Broadly elliptical or hexagonal, with long rim spines, and diagonal cross bars. | ||
![]() | ![]() | ![]() | ![]() | Stephanolithion brevispinus Elliptical, with very short rim spines, and diagonal cross bars. | |
![]() | ![]() | ![]() | Stephanolithion hexum Elliptical, with multiple rim spines and six cross bars. | ||
![]() | ![]() | ![]() | ![]() | Stephanolithion speciosum Elliptical with multiple short rim spines and eight cross bars. | |
Stephanolithion sp. Specimens not identified to species level |
Taxonomy:
Farinacci & Howe catalog pages: Stephanolithion * , Paractinozygus + *
Distinguishing features: Elliptical and often polygonal; rims low but broad, bicyclic; central-area spanned by one to eight bars; prominent spines protrude from the rim
Morphology: Elliptical and often polygonal murolith (protolith) coccoliths with spines that protrude from the rim. The rims are low but relatively broad, have weakly-developed proximal/inner-cycles, and a central-area spanned by one to eight bars, supporting a central spine. LM image is usually bicyclic but the outer dark cycle of V-units is better developed than the inner cycle of R-units and the central structure non-birefringent, so they are best viewed in phase contrast. The rim spines are formed by outwrd growth of single V-units from the rim.
Tags | LITHS: murolith, elliptical, CA: ca_disjunct, process, diagonal cross, CROSS-POLARS: rim-bicyclic, V-prominent, |
Metrics | Lith size: 4->9µm; Data source notes: size range of included species |
Geological Range:
Last occurrence (top): in mid part of Tithonian Stage (53% up, 148.3Ma, in Tithonian stage). Data source: Total of range of species in this database
First occurrence (base): in lower part of Bajocian Stage (31% up, 169.7Ma, in Bajocian stage). Data source: Total of range 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 Deflandre, G. (1939). Les stéphanolithes, représentants d'un type nouveau de coccolithes Jurassique supérieur. Comptes Rendus Hebdomadaires des Séances de l'Académie des Sciences, Paris. 208: 1331-1333. gs V O Missing or ambiguous references: Cooper 1987; References:
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Stephanolithion compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 28-1-2021
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