Percivalia


Classification: Mesozoic -> Eiffellithales -> Rhagodiscaceae -> Percivalia
Sister taxa: Calcicalathina, Percivalia, Rhagodiscus, Zebrashapka,

Distinguishing features: Loxolith coccoliths with narrow outer cycle and wide central area filled with a granular plate or bridge.


Daughter taxa: (blue => in age window 0-800Ma)


Central area filled by indistinct cross transverse bar of which apears as "bright buttons"
Loxolith coccoliths with narrow outer cycle and wide central area filled with a granular plate. The plate is distinctly smooth and birefringent in XPL and crossed by curving extinction lines.



Central area filled by dark axial cross


Specimens not identified to species level

Taxonomy:

Citation: Percivalia Bukry, 1969
Rank: Genus
Type species: Percivalia porosa Bukry, 1969

Farinacci & Howe catalog pages: Percivalia *

Distinguishing features: Loxolith coccoliths with narrow outer cycle and wide central area filled with a granular plate or bridge.


Morphology remarks: Rather poorly constrained and applied genus. Nature of the type species, described from EM, is uncertain.

Geological Range:
Last occurrence (top): within Maastrichtian Stage (66.04-72.05Ma, top in Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): within Tithonian Stage (145.01-152.06Ma, base in Tithonian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Bown, P.R.; Rutledge, D.C.; Crux, J.A. & Gallagher, L.T., (1998). Early Cretaceous. In: Bown, P.R. (Editor), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publication Series. Chapman & Hall, pp. 86-131. GS

Bukry, D. (1969). Upper Cretaceous coccoliths from Texas and Europe. The University of Kansas Paleontological Contributions, Article 51 (Protista 2): 1-79. GS

Burnett, J.A., (1998). Upper Cretaceous. In: Bown, P.R. (Editor), Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publications Series. Chapman & Hall, London, pp. 132-199. GS


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Percivalia compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 25-5-2019

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10870 Go to Archive.is to create a permanent copy of this page - citation notes



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