Distinguishing features:
Parent taxon (Eiffellithales): Murolith coccoliths with an upper/outer cycle of clockwise-imbricate V-units and a lower/inner cycle of R-units.
This taxon: Eiffelithales with V-units forming most of rim (R-units typically thin plates on proximal surface, so LM images are typically unicyclic. Central-areas typically filled by a plate of granular calcite. The central structure may be spine-bearing, perforate or massive.
Daughter taxa (time control age-window is: 0-800Ma)![]() | Granddaughter taxa | ||||
![]() | ![]() | ![]() | ![]() | Percivalia Loxolith coccoliths with narrow outer cycle and wide central area filled with a granular plate or bridge, multiple concentric cycles seen on proximal face. | P. arata P. bullata P. dunkleyjonesii P. fenestrata P. hauxtonensis P. howardii P. imperfossa P. pearsonii P. pontilitha P. porosa P. nebulosa P. sp. |
![]() | ![]() | Rhagodiscus Loxolith coccoliths with low rim and central-area filled by a granular plate which may be perforate and/or spine-bearing. In xpl the rim is unicyclic moderately bright, the central area is granular, lacking a clear extinction cross. | R. achlyostaurion R. amplus R. angustus R. asper R. cepekii R. dekaenelii R. infinitus R. pseudoangustus R. splendens R. adinfinitus R. gallagheri R. indistinctus R. pancostii R. plebeius R. robustus R. sageri R. eboracensis R. hamptonii R. reniformis R. sp. | ||
Central area filled by mass of small elements | |||||
![]() | ![]() | ![]() | ![]() | Calcicalathina Muroliths (loxolith type) with high, narrow rim and wide central-area filled by a large, domed, granular mass. | |
Zebrashapka Solid, truncated-cone-shaped coccolith (possibly a holococcolith), with distinct outer rim and banded core. |
Taxonomy:
Farinacci & Howe catalog pages: Rhagodiscaceae [no catalog entry yet]
Distinguishing features:
Parent taxon (Eiffellithales): Murolith coccoliths with an upper/outer cycle of clockwise-imbricate V-units and a lower/inner cycle of R-units.
This taxon: Eiffelithales with V-units forming most of rim (R-units typically thin plates on proximal surface, so LM images are typically unicyclic. Central-areas typically filled by a plate of granular calcite. The central structure may be spine-bearing, perforate or massive.
Morphology:
Size:
Tags | LITHS: murolith, |
Metrics | Lith size: 0->0µm; |
Geological Range:
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Danian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Tithonian Stage (0% up, 152.1Ma, in Kimmeridgian stage). Data source: Total of range of species in this database
Plot of occurrence data:
Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs Hay, W. W. (1977). Calcareous nannofossils. In, Ramsay, A. T. S. (ed.) Oceanic Micropalaentology. Academic Press, London 1055-1200. gsReferences:
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Rhagodiscaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 23-5-2022
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=11011 Go to Archive.is to create a permanent copy of this page - citation notes |
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