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