Nannotax3 - ntax_mesozoic - Mitrolithus Nannotax3 - ntax_mesozoic - Mitrolithus

Mitrolithus


Classification: ntax_mesozoic -> Stephanolithiales -> Parhabdolithaceae -> Mitrolithus
Sister taxa: Bucanthus, Calcivascularis, Crucirhabdus, Diductius, Mitrolithus, Parhabdolithus, Timorella, Umbria

Distinguishing features:
Parent taxon (Parhabdolithaceae): Murolith (protolith type) coccoliths with bicylic rims and central-areas spanned by an axial-cross or transverse bar bearing a broad, often long, spine.
This taxon: Protolith coccoliths with high rim with broad proximal/inner rim cycle; central area filled by a massive boss/spine. Often seen in side view


Daughter taxa (time control age-window is: 0-800Ma)
Mitrolithus elegans
Mitrolithus with steeply sloping, high rim with very wide inner cycle on which sits a lens-shaped spine. Bicyclic rim image in XPL with distinctive broad, bright inner cycle and no central opening. Often seen in side view revealing the distinctive lens-shaped spines. Detached spines are circular in plan view (described as Alvearium dorsetense Black, 1965).
Mitrolithus lenticularis
Mitrolithus with a spine that fits neatly into the rim forming a flush, domed upper surface.
Mitrolithus sp.
Specimens not identified to species level

Taxonomy:

Citation: Mitrolithus Deflandre in Deflandre & Fert, 1954
Taxonomic rank: genus
Type species: Mitrolithus elegans Deflandre in Deflandre and Fert, 1954
Synonyms: Alvearium Black 1967

Farinacci & Howe catalog pages: Mitrolithus + * , Alvearium *

Distinguishing features:
Parent taxon (Parhabdolithaceae): Murolith (protolith type) coccoliths with bicylic rims and central-areas spanned by an axial-cross or transverse bar bearing a broad, often long, spine.
This taxon: Protolith coccoliths with high rim with broad proximal/inner rim cycle; central area filled by a massive boss/spine. Often seen in side view


Morphology:

Protolith coccoliths with high rim and broad proximal/inner rim cycle on which sits a massive boss/spine. Bicyclic rim image in XPL, but often seen in side view revealing the distinctive spines.

Search data:
LITHS: murolith, elliptical, cylindrical, CA: process, ca_disjunct, CROSS-POLARS: R-prominent, V-prominent, rim-bicyclic,
Lith size: 4->7µm;
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 NJT7b subzone (100% up, 180.4Ma, in Toarcian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NJ2a subzone (197.26-199.66Ma, base in Hettangian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

References:

Black, M. (1967). New names for some coccolith taxa. Proceedings of the Geological Society of London. 1640: 139-145. gs

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 O

Bown, P. R. & Young, J. R. (1997). Mesozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 21-36. 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


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Mitrolithus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-2-2025

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10692 Go to Archive.is to create a permanent copy of this page - citation notes
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