Distinguishing features: Parent taxon (Arkhangelskiales): Tiered placoliths with 3-5 closely-appressed shields. This taxon: Arkhangelskielids with shields predominantly formed of R-units, thus bright in cross-polarised light; V-units often form dark outer rim.
Daughter taxa (time control age-window is: 0-800Ma)
Granddaughter taxa
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.
Broinsonia Outer rim of V-units, with slight clockwise obliquity, visible on distal surface and form dark rim in LM; central-area spanned by an axial cross, grill or perforate plate. 3 tiers visible in side view.
Distinguishing features: Parent taxon (Arkhangelskiales): Tiered placoliths with 3-5 closely-appressed shields. This taxon: Arkhangelskielids with shields predominantly formed of R-units, thus bright in cross-polarised light; V-units often form dark outer rim.
Morphology: Tiered placolith coccoliths with central-areas spanned by axial crosses and grills, or filled by a perforate plate divided by axial sutures. The shields are typically bright in cross polarised light (rim dominated by R-unit) but bicyclic images are also observed.
Moshkovitz & Osmond (1989) analyse the birefringence pattern in detail. Size:
Search data:
Tags
LITHS: placolith,
Metrics
Lith size: 0->0µm;
The morphological data given here can be used on the advanced search page. See also these notes
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 Valanginian Stage (0% up, 139.4Ma, in Berriasian stage). Data source: Total of range of species in this database
Plot of occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
Neptune data: this is a higher taxon page so Neptune data is not plotted. For the customisable plot option go to a genus page Parent: Arkhangelskiales
References:
Bown, P. R. & Young, J. R. (1997). Mesozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 21-36. gsVO
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
Bukry, D. (1969). Upper Cretaceous coccoliths from Texas and Europe. University of Kansas Paleontological Contributions, Articles. 51 (Protista 2): 1-79. gsO
Moshkovitz, S. & Osmond, K. (1989). The optical properties and microcrystallography of Arkhangelskiellaceae and some other calcareous nannofossils of the Late Cretaceous. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications: Proceedings of the 2nd INA Conference, London 1987. British Micropalaeontological Society Publication Series. 76-97. gs
Vekshina, V. N. (1959). Coccolithophoridae of the Maastrichtian deposits of the West Siberian lowlands. Trudyi Instituta Geologii i Geogiziki, Sibiriskoe Otlodelenie, Akademiya Nauk SSSR (Nauka) Moscow. 2: 56-81. gs
Arkhangelskiellaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 23-5-2022
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