Distinguishing features:
Parent taxon (Lithastrinus): Eprolithids with two cycles of five to seven ray-like, curved, wall-cycle elements surrounding a narrow median diaphragm.
This taxon: 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.
Taxonomy:
Farinacci & Howe catalog pages: L. quadricuspis + *
Distinguishing features:
Parent taxon (Lithastrinus): Eprolithids with two cycles of five to seven ray-like, curved, wall-cycle elements surrounding a narrow median diaphragm.
This taxon: 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.
Most likely ancestor: Lithastrinus pentabrachius - at confidence level 2 (out of 5). Data source: Varol 1992.
Search data:LITHS: nannolith-radiate, quadrate, star-shaped, CA: closed, CROSS-POLARS: T-prominent, |
Lith size: 7->12µm; Segments: 4->4; Data source notes: original description +/-1µm |
Geological Range:
Last occurrence (top): within Maastrichtian Stage (66.04-72.17Ma, top in Maastrichtian stage). Data source: Burnett 1998
First occurrence (base): within UC15b subzone (77.56-79.13Ma, base in Campanian stage). Data source: Burnett 1998
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 Farhan, A. (1987). Evolutionary Trend of the Genus Lithastrinus to the Genus Uniplanarius. Abhandlungen der Geologischen Bundesanstalt. 39: 57-65. gs Lees, J. A. & Bown, P. R. (2005). Upper Cretaceous calcareous nannofossil biostratigraphy, ODP Leg 198 (Shatsky Rise, Northwest Pacific Ocean). Proceedings of the Ocean Drilling Program, Scientific Results. 198: 1-60. gs References:
Lithastrinus quadricuspis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 8-9-2024
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10572 Go to Archive.is to create a permanent copy of this page - citation notes |
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