Nannotax3 - ntax_mesozoic - Mitrolithus elegans

Mitrolithus elegans


Classification: ntax_mesozoic -> Stephanolithiales -> Parhabdolithaceae -> Mitrolithus -> Mitrolithus elegans
Sister taxa: M. elegans, M. lenticularis, M. sp.

Distinguishing features:
Parent taxon (Mitrolithus): Protolith coccoliths with high rim with broad proximal/inner rim cycle; central area filled by a massive boss/spine. Often seen in side view
This taxon: 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).


Taxonomy:

Citation: Mitrolithus elegans Deflandre in Deflandre & Fert, 1954
Rank: Species
Synonyms: Alvearium dorsetense Black, 1965
Variants: Mattioli in Abdi et al. 2022, has described three new species of Mitrolithus from the Late Sinemurian of Iran - these are similar to M. elegans but with expanded spines.

Farinacci & Howe catalog pages: M. elegans * , A. dorsetense * , M. montgolfieri * , M. pseudonannoconus * , M. tethysiensis *

Distinguishing features:
Parent taxon (Mitrolithus): Protolith coccoliths with high rim with broad proximal/inner rim cycle; central area filled by a massive boss/spine. Often seen in side view
This taxon: 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).


Morphology:


Size:


Ecology & Biogeography


Biology & life-cycles

Phylogenetic relations

Search data:
LITHS: murolith, circular, elliptical, cylindrical, CA: ca_disjunct, process, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,
Lith size: 4->7µm;
Data source notes: Bown 1987
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within Late Pliensbachian Substage (182.70-187.56Ma, top in Pliensbachian stage). Data source: Bown & Cooper 1998
First occurrence (base): at base of NJ2a subzone (0% up, 199.5Ma, in Hettangian stage). Data source: Bown & Cooper 1998 (fig. 4) - secondary events; Mattioli & Erba 1999

Plot of occurrence data:

References:

Abdi, A., Mattioli, E. & Bádenas, B. (2022). A new calcareous nannofossil record from the Lower Jurassic of Kermanshah, Western Iran: implications for biostratigraphy and evolutionary reconstructions. Geosciences. 12(59): 1-17. gs V O

Black, M. (1965). Coccoliths. Endeavour. 24: 131-137. 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. (1987a). Taxonomy, evolution, and biostratigraphy of Late Triassic-Early Jurassic calcareous nannofossils. Special Papers in Palaeontology. 38: 1-118. gs

Bown, P. R. (1987b). The structural development of Early Mesozoic coccoliths and its evolutionary and taxonomic significance. Abhandlungen der Geologischen Bundesanstalt. 39: 33-49. gs V O

Crux, J. A. (1987b). Early Jurassic calcareous nannofossil biostratigraphic events. Newsletters on Stratigraphy. 17: 79-100. gs V O

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

Kristan-Tollmann, E. (1988b). Coccolithen aus den Älteren Allgäuschichten (Alpiner Lias, Sinemur) von Timor, Indonesien. Geologisch-Paläontologische Mitteilungen Innsbruck. 15: 71-83. gs V O

Mattioli, E. & Erba, E. (1999). Synthesis of calcareous nannofossil events in Tethyan lower and middle Jurassic successions. Rivista Italiana di Paleontologia e Stratigrafia. 105(3): 343-376. gs V O

Prins, B. (1969). Evolution and stratigraphy of cocolithinids from the Lower and Middle Lias. In, Bronnimann, P. & Renz, H. H. (eds) Proceedings of the First International Conference on Planktonic Microfossils, Geneva 1967. E. J. Brill, Leiden 547-558. gs

Rood, A. P., Hay, W. W. & Barnard, T. (1973). Electron microscope studies of Lower and Middle Jurassic coccoliths. Eclogae Geologicae Helvetiae. 66: 365-382. gs O


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Mitrolithus elegans compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 3-12-2022

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10693 Go to Archive.is to create a permanent copy of this page - citation notes



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