Distinguishing features:
Parent taxon (Polycyclolithaceae): Nannoliths composed of two superposed wall cycles and a central-area which may be closed, open and vacant, or spanned by a diaphragm-like structure. Elements have tangential c-axis orientation.
This taxon: Eprolithids with two cycles of five to seven ray-like, curved, wall-cycle elements surrounding a narrow median diaphragm.
Daughter taxa (time control age-window is: 0-800Ma) | ||||
Lithastrinus quadricuspis Nannolith with two superposed cycles of four ray-like elements with a narrow central diaphragm. One cycle has long narrow rays and the other has much shorter rays. | ||||
Lithastrinus pentabrachius Lithastrinus with five petaloid wall-elements | ||||
Lithastrinus grillii Lithastrinus with six twisting petaloid wall-elements surrounding a narrow central area. | ||||
Lithastrinus septenarius Lithastrinus with seven narrow, curving wall-elements surrounding a narrow central area. | ||||
Lithastrinus sp. Specimens not identified to species level |
Taxonomy:
Farinacci & Howe catalog pages: Lithastrinus + * , Astrionis *
Distinguishing features:
Parent taxon (Polycyclolithaceae): Nannoliths composed of two superposed wall cycles and a central-area which may be closed, open and vacant, or spanned by a diaphragm-like structure. Elements have tangential c-axis orientation.
This taxon: Eprolithids with two cycles of five to seven ray-like, curved, wall-cycle elements surrounding a narrow median diaphragm.
Search data:
LITHS: nannolith-radiate, pentagonal, quadrate, star-shaped, CA: closed, |
Lith size: 5->15µm; Data source notes: size range of included species |
Geological Range:
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Danian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within UC9a subzone (89.95-90.14Ma, base in Turonian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gs O Stradner, H. (1962). Über neue und wenig bekannte Nannofossilien aus Kreide und Alttertiär. Verhandlungen der Geologischen Bundesanstalt (Wien). 2: 363-377. gs References:
Lithastrinus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 12-10-2024
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10569 Go to Archive.is to create a permanent copy of this page - citation notes |
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