Broinsonia


Classification: Mesozoic -> Arkhangelskiales -> Arkhangelskiellaceae -> Broinsonia
Sister taxa: Arkhangelskiella, Broinsonia, Thiersteinia

Distinguishing features: 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: (blue => in age window 0-800Ma) Granddaughter taxa
Species with plate
Broinsonia parca
Large (>9 µm) central structure perforate plate; rim broad.

Broinsonia enormis
Medium-sized (<9 µm); central structure imperforate plate; rim broad

Broinsonia furtiva
Axial cross with rows of closely spaced pores parallel to cross bars forming elongate perforations

Broinsonia gammation
small (<5µm) species with perforate plate surrounding central cross

Species with lateral bars
Broinsonia verecundia
small (<6µm) elongate species with lozenge-like central body and lateral bars

Broinsonia dentata
axial cross with lateral bars

Broinsonia cenomanica
axial cross with lateral bars, supporting low spine

Species with fine grill
Broinsonia ethmoquadrata
axial cross and fine grill

Species open quadrants
Broinsonia signata
axial cross with open quadrants

Broinsonia galloisii
Small Broinsonia (<5.5µm) with broad axial cross bars.

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, 1969
Rank: Genus
Type species: Broinsonia dentata Bukry, 1969
Synonyms: Acaenolithus Black, 1973; Aspidolithus Noel, 1969
Taxonomic 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. Perch-Nielsen 1985) for forms with an axial cross, and Aspidolithus for those with a central plate.

Farinacci & Howe catalog pages: Broinsonia * , Acaenolithus * , Aspidolithus *

Distinguishing features: 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.

Search data:
TagsLITHS: placolith, elliptical, CA: cross-axial, grill, plate, pores, process, closed, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
MetricsLith 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 Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Valanginian Stage (0% up, 139.4Ma, in Valanginian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

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). 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. gs V O

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

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. (1985b). Mesozoic calcareous nannofossils. In, Bolli, H. M. , Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 329-426. gs


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Broinsonia compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 24-11-2020

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10118 Go to Archive.is to create a permanent copy of this page - citation notes



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