Crepidolithus


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

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


Daughter taxa: (blue => in age window 0-800Ma)
Unicyclic in xpl
Large blocky Crepidolithus ; rim broad; central opening narrow, lenticular. Unicyclic in xpl.
Crepidolithus with low rim; central area wide, with granular plate and small spine/spine base. Unicyclic in xpl.
Very small (<4µm) Crepidolithus ; rim broad. Unicyclic in xpl.
Crepidolithus with narrow rim and wide central area spanned by a finely perforate proximal net. Unicyclic in xpl
Crepidolithus with broad, high rim; central area narrow, lenticular almost filled by a low spine. Unicyclic in xpl
Small(<4.5µm) Crepidolithus with broad very high rim; central area narrow with a low spine. Unicyclic in xpl.
Bicyclic in xpl
Medium-sized Crepidolithus with moderately broad rim; central area open. Bicyclic in xpl
Crepidolithus with moderately broad rim; central area with axial cross
Crepidolithus with narrow rim; central area wide with delicate transverse bar. Bicyclic in xpl
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: Millbrookia Medd 1979 (the type species M.perforata is now placed in Crepidolithus)
Notes & 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 *

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


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

Geological Range:
Last occurrence (top): at top of Tithonian Stage (100% up, 145Ma, in Tithonian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Sinemurian Stage (0% up, 199.3Ma, in Sinemurian 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. (1965). Sur les Coccolithes du Jurassique Européen et d'Afrique du Nord. Éditions du Centre National de la Recherche Scientifique, Paris. -. gs


nannotaxlogo400px

Crepidolithus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-12-2019

Taxon Search:
Advanced Search

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



Comments (0)

No comments yet. Be the first!

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics