Zeugrhabdotus streetiae


Classification: ntax_mesozoic -> Eiffellithales -> Chiastozygaceae -> Zeugrhabdotus -> Zeugrhabdotus streetiae
Sister taxa: Z. blowii, Z. burolletii, Z. burwellensis, Z. erectus, Z. fissus, Z. moulladei, Z. noeliae ⟩⟨ Z. bicrescenticus, Z. diplogrammus, Z. fluxus, Z. howei, Z. petrizzoae, Z. reticulatus, Z. scutula ⟩⟨ Z. biperforatus, Z. kerguelenensis, Z. large spine, Z. clubhousensis ⟩⟨ Z. clarus, Z. acanthus, Z. trivectis, Z. xenotus ⟩⟨ Z. angelozziae, Z. cooperi, Z. embergeri, Z. praesigmoides, Z. sigmoides, Z. simplex, Z. streetiae, Z. sp.

Distinguishing features: Bicycle, large; bar complex, appears x-shaped in some views.


Taxonomy:

Citation: Zeugrhabdotus streetiae Bown in Kennedy et al., 2000
Rank: Species
Taxonomic discussion: This species seems very similar to Amphizygus brooksii

Farinacci & Howe catalog pages: Z. streetiae *

Distinguishing features: Bicycle, large; bar complex, appears x-shaped in some views.


Morphology: Large (c. 8.0 µm) Zeugrhabdotus with a broad, bicyclic or diffusely bicyclic rim and a broad, complexely constructed transverse bar. When oriented parallel to the polarising directions, the bar appears granular but weakly birefringent and broadens markedly towards the rim; in this orientation the most birefringent parts of the bar may appear as an acute diagonal cross. When oriented at 45° to the polarising directions, the bar is dark at one focus level and bright protrusions from the inner rim cycle are visible; if the focus level is shifted, the bar becomes birefringent and appears as a bright rectangle crossed by diagonal extinction lines. In PC, the bright inner cycle is only seen clearly at either end of the bar.

Size: Length 7.1-9.0 µm

Search data:
TagsLITHS: murolith, ca_disjunct, process, bar, CROSS-POLARS: rim-bicyclic, V-prominent,
MetricsLith size: 7->9µm;
Data source notes: original description
The morphological data given here can be used on the advanced search page. See also these notes

See also: Amphizygus brooksii - possible senior synonym;

Geological Range:
Last occurrence (top): within Late Albian Substage (100.50-107.59Ma, top in Albian stage). Data source: Kennedy et al., 2000
First occurrence (base): within Late Aptian Substage (112.95-122.98Ma, base in Aptian stage). Data source: Kennedy et al., 2000

Plot of occurrence data:

References:

Bown, P. R. (2001). Calcareous nannofossils of the Gault, Upper Greensand and Glauconitic Marl (Middle Albian-Lower Cenomanian) from the BGS Selborne boreholes, Hampshire. Proceedings of the Geologists' Association. 112: 223-236. gs

Bown, P. R. (2005c). Early to Mid-Cretaceous Calcareous Nannoplankton from the Northwest Pacific Ocean, Leg 198, Shatsky Rise. Proceedings of the Ocean Drilling Program, Scientific Results. 198: 1-82. gs V O

Gale, A. S. et al. (2011). The uppermost Middle and Upper Albian succession at the Col de Palluel, Hautes-Alpes, France: An integrated study (ammonites, inoceramid bivalves, planktonic foraminifera, nannofossils, geochemistry, stable oxygen and carbon isotopes, cyclostratigraphy). Cretaceous Research. 32: 59-130. gs

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


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Zeugrhabdotus streetiae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 19-1-2021

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=11346 Go to Archive.is to create a permanent copy of this page - citation notes



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