Nannotax3 - ntax_mesozoic - Archaeozygodiscus

Archaeozygodiscus


Classification: ntax_mesozoic -> Eiffellithales -> Chiastozygaceae -> Archaeozygodiscus
Sister taxa: Amphizygus, Archaeozygodiscus, Gorkaea, Placozygus, Reinhardtites, Tranolithus, Zeugrhabdotus ⟩⟨ Chiastozygus ⟩⟨ Staurolithites, Diadorhombus, Rhabdophidites ⟩⟨ Ahmuellerella, Bukrylithus, Diloma, Heteromarginatus, Misceomarginatus, Monomarginatus, Vacherauvillius ⟩⟨ Braloweria, Clepsilithus, Crepidolithus, Loxolithus, Neocrepidolithus, Tubirhabdus, C. - unidentified

Distinguishing features:
Parent taxon (Chiastozygaceae): Typical Eiffelithales - rim with well outer/upper clockwise-imbricate V-units and lower/inner R-units. Central area open or spanned by disjunct cross or bar supporting a spine.
This taxon: Bicyclic (LM) murolith with a birefringent, spine-bearing bar. Distal/outer-cycle displays anticlockwise imbrication, unlike all other Mesozoic loxoliths. Triassic genus.


Daughter taxa (time control age-window is: 0-800Ma)
Archaeozygodiscus koessenensis
Small Archaeozygodiscus loxolith coccoliths with spine bearing transverse bar.
Archaeozygodiscus sp.
Specimens not identified to species level

Taxonomy:

Citation: Archaeozygodiscus Bown, 1985
Rank: Genus
Type species: Archaeozygodiscus koesseni Bown 1985

Farinacci & Howe catalog pages: Archaeozygodiscus *

Distinguishing features:
Parent taxon (Chiastozygaceae): Typical Eiffelithales - rim with well outer/upper clockwise-imbricate V-units and lower/inner R-units. Central area open or spanned by disjunct cross or bar supporting a spine.
This taxon: Bicyclic (LM) murolith with a birefringent, spine-bearing bar. Distal/outer-cycle displays anticlockwise imbrication, unlike all other Mesozoic loxoliths. Triassic genus.

Search data:
TagsLITHS: murolith, elliptical, CA: ca_disjunct, process, bar, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
MetricsLith size: 2->4µm;
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): near base of Hettangian Stage (10% up, 201.1Ma, in Hettangian stage). Data source: Total of range of species in this database
First occurrence (base): in mid part of Norian Stage (50% up, 218.9Ma, in Norian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Bown, P. R. (1985). Archaeozygodiscus gen. nov. and other Triassic coccoliths. INA Newsletter. 7: 32-34. gs V O

Bown, P. R. (1998b). Triassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 29-33. gs


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Archaeozygodiscus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 28-11-2021

Taxon Search:
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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10031 Go to Archive.is to create a permanent copy of this page - citation notes



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