Distinguishing features: Parent taxon (Arkhangelskiellaceae): Arkhangelskielids with shields predominantly formed of R-units, thus bright in cross-polarised light; V-units often form dark outer rim. This taxon: 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.
Daughter taxa (time control age-window is: 0-800Ma)
Granddaughter taxa
Species with plate
Broinsonia parca Large (>9 µm) central structure perforate plate; rim broad.
Broinsonia matalosa Medium Broinsonia (5.5-8 µm) with broad axial cross bars.
Broinsonia viriosa Large Broinsonia (>8 µm) with broad axial cross bars.
Broinsonia sp. Specimens not identified to species level
Taxonomy:
Citation: Broinsonia Bukry, 1969taxonomic rank: GenusType species: Broinsonia dentata Bukry, 1969Synonyms: Acaenolithus Black, 1973; Aspidolithus Noel, 1969Taxonomic discussion: Black (1973) described the genus Acaenolithus for “coccoliths in most respects resembling Broinsonia Bukry, 1969, but differing in the presence of a knob or spine at the centre of the distal surface”. We consider this genus a junior synonym of Broinsonia - see also discussion by Bown in Kennedy et al. 2000. Aspidolithus Nöel (1969) was published slightly after Broinsonia Bukry (1969) and Nöel (1970) placed the genera in synonymy. Nonetheless, Broinsonia has been used by some authors (e.g. Lauer 1975, Perch-Nielsen 1985) for forms with an axial cross, and Aspidolithus for those with a central plate.
Distinguishing features: Parent taxon (Arkhangelskiellaceae): Arkhangelskielids with shields predominantly formed of R-units, thus bright in cross-polarised light; V-units often form dark outer rim. This taxon: 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.
Morphology: The LM image is typically bicyclic, with a broad, bright inner-cycle and narrow, dark outer-cycle. The central structure typically includes a boss or spine. In the SEM in side view three tiers of elements are visible (vs. four in Arkhangelskiella). In the SEM in distal view two cycles of elements are visible, an outer one usualy with well developed sutures showing weak dextral obliquity, and an inner one with obscured surures and often a fluted surface.
Lith size: 3->15µm; Data source notes: size range of included species
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 ranges of the species in this database First occurrence (base): within Valanginian Stage (132.60-137.70Ma, base in Valanginian stage). Data source: Total of ranges 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
Black, M. (1973). British Lower Cretaceous Coccoliths. I-Gault Clay (Part 2). Palaeontographical Society Monograph. 127: 49-112. gs
Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Lower Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 86-131. gsO
Bukry, D. (1969). Upper Cretaceous coccoliths from Texas and Europe. University of Kansas Paleontological Contributions, Articles. 51 (Protista 2): 1-79. gsO
Kennedy, W. J. et al. (2000). Integrated stratigraphy across the Aptian-Albian boundary in the Marnes Bleues, at the Col de Pre _-Guittard, Arnayon (Drome), and at Tartonne (Alpes-de-Haute-Provence), France: a candidate Global Boundary Stratotype Section and Boundary Point for the base of the Albian Stage. Cretaceous Research. 21: 591-720. gs
Lauer, G. (1975). Evolutionary trends in the Arkhangelskiellaceae (calcareous nannoplankton) of the Upper Cretaceous of Central Oman, SE Arabia. In, Noel. D. & Perch-Nielsen, K. (eds) Report of the consultant group on calcareous nannoplankton, Kiel. Archives des Sciences . 28(317): 259-262. gs
Noël, D. (1969). Arkhangelskiella (coccolithes Crétacés) et formes affines du Bassin de Paris. Revue de Micropaléontologie. 11: 191-204. gs
Noël, D. (1970). Coccolithes Crétacés: La Craie Campanienne du Bassin de Paris. Éditions du Centre National de la Recherche Scientifique, Paris. -. gs
Perch-Nielsen, K. (1985). Mesozoic calcareous nannofossils. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge (1): 329-426. gs
Broinsonia compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 9-10-2024
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