Nannotax3 - ntax_mesozoic - Crepidolithus

Crepidolithus


Classification: ntax_mesozoic -> Eiffellithales -> Chiastozygaceae -> Crepidolithus
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: Murolith (loxoliths) with a robust, broad, high rim and central area that may be vacant, closed or spanned by bars or grill.


Daughter taxa (time control age-window is: 0-800Ma)
Unicyclic in xpl
Crepidolithus crassus
Large blocky Crepidolithus ; rim broad; central opening narrow, lenticular. Unicyclic in xpl.
Crepidolithus granulatus
Crepidolithus with low rim; central area wide, with granular plate and small spine/spine base. Unicyclic in xpl.
Crepidolithus parvulus
Very small (<4µm) Crepidolithus ; rim broad. Unicyclic in xpl.
Crepidolithus perforatus
Crepidolithus with narrow rim and wide central area spanned by a finely perforate proximal net. Unicyclic in xpl
Crepidolithus pliensbachensis
Crepidolithus with broad, high rim; central area narrow, lenticular almost filled by a low spine. Unicyclic in xpl
Crepidolithus timorensis
Small(<4.5µm) Crepidolithus with broad, very high, rim; central area narrow with a low spine. Unicyclic in xpl.
Bicyclic in xpl
Crepidolithus cantabriensis
Medium-sized Crepidolithus with moderately broad rim; central area open. Bicyclic in xpl
Crepidolithus impontus
Crepidolithus with narrow rim; central area wide with delicate transverse bar. Bicyclic in xpl
Crepidolithus sp.
Specimens not identified to species level

Taxonomy:

Citation: Crepidolithus Noël, 1965
Rank: Genus
Type species: Crepidolithus crassus (Deflandre in Deflandre and Fert, 1954) Noël, 1965.
Synonyms:

Taxonomic discussion:
The speies are arranged inthe table according to whether they have a uncyclic or bicylic rim image in cross-plarised light. This helps to clarify the species-level taxonomy, but is not necessarily a robust basis for dividing the group.

Farinacci & Howe catalog pages: Crepidolithus * , Millbrookia * , Timorhabdus *

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: Murolith (loxoliths) with a robust, broad, high rim and central area that may be vacant, closed or spanned by bars or grill.


Morphology: Typically large blocky coccoliths that appear unicyclic in XPL and are often seen in side view.

Search data:
TagsLITHS: murolith, elliptical, CA: ca_disjunct, grill, vacant, process, bar, closed, CROSS-POLARS: rim-bicyclic, rim-unicyclic,
MetricsLith size: 2->9µm;
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 Tithonian Stage (100% up, 145Ma, in Berriasian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Sinemurian Stage (0% up, 199.3Ma, in Hettangian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Bown, P. R. & Cooper, M. K. E. (1998). Jurassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 34-85. gs

Deflandre, G. & Fert, C. (1954). Observations sur les coccolithophoridés actuels et fossiles en microscopie ordinaire et électronique. Annales de Paléontologie. 40: 115-176. gs

Noël, D. (1965b). Sur les Coccolithes du Jurassique Européen et d'Afrique du Nord. Essai de classification des coccolithes fossiles. Éditions du Centre National de la Recherche Scientifique, Paris. 1-209. gs


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

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10286 Go to Archive.is to create a permanent copy of this page - citation notes



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