Distinguishing features:
Parent taxon (Arkhangelskiella): R-units cover the distal surface, so coccolith appears bright, unicyclic, in LM (although darker towards outer edge); central-area has perforate plate with axial sutures. 4 tiers visible in side view.
This taxon: Small to medium sized (4-8µm), with a <1.5µm thick rim
Taxonomy:
Farinacci & Howe catalog pages: A. confusus * , A. cymbiformis N *
Distinguishing features:
Parent taxon (Arkhangelskiella): R-units cover the distal surface, so coccolith appears bright, unicyclic, in LM (although darker towards outer edge); central-area has perforate plate with axial sutures. 4 tiers visible in side view.
This taxon: Small to medium sized (4-8µm), with a <1.5µm thick rim
Search data:
LITHS: placolith, elliptical, CA: plate, |
Lith size: 0->0µm; |
Geological Range:
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Danian stage). Data source: Lees & Bown 2005 - consistently present to end Cret
First occurrence (base): within Coniacian Stage (85.70-89.39Ma, base in Coniacian stage). Data source: Burnett 1997
Plot of occurrence data:
Burnett, J. A. (1997c). New species and new combinations of Cretaceous nannofossils and a note on the origin of Petrarhabdus (Deflandre) Wise & Wind. Journal of Nannoplankton Research. 19(2): 133-146. gs Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gs O Lees, J. A. & Bown, P. R. (2005). Upper Cretaceous calcareous nannofossil biostratigraphy, ODP Leg 198 (Shatsky Rise, Northwest Pacific Ocean). Proceedings of the Ocean Drilling Program, Scientific Results. 198: 1-60. gs Thibault, N. (2010). Calcareous nannofossils from the boreal Upper Campanian- Maastrichtian chalk of Denmark. Journal of Nannoplankton Research. 31(1): 39-56. gs Varol, O. (1989d). Quantitative analysis of the Arkhangelskiella cymbiformis group and its biostratigraphical usefulness in the North Sea area. Journal of Micropalaeontology. 8: 131-134. gs Missing or ambiguous references: ; ; References:
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Arkhangelskiella confusa compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-5-2025
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10036 Go to Archive.is to create a permanent copy of this page - citation notes |
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Comments (2)
I think it would be great in the future development of nannotax to add for each species information on size like size range, mean, etc with a small indication if it is from a large amount of specimen or not.
Thank you very and congratulations again for this brilliant website.
Baptiste
You are quite right it would be a very useful to have good data on coccolith sizes and this is one of the things we would like to add - but the problem is to find useful compendiums of data. If you have any suggestions for data sources please feel free to make them. .. but thanks anyway for the feedback.
Jeremy