Distinguishing features:
Parent taxon (Quadrum): Stellate to cubiform nannoliths with walls formed from two cycles of 4-9 elements and no central opening or diaphragm. When cubiform, the elements are joined along sutures that go out to the mid-point of the 'cube' edges.
This taxon: Quadrum with one cycle larger than the other.
Taxonomy:
Farinacci & Howe catalog pages: Q. bengalensis *
Distinguishing features:
Parent taxon (Quadrum): Stellate to cubiform nannoliths with walls formed from two cycles of 4-9 elements and no central opening or diaphragm. When cubiform, the elements are joined along sutures that go out to the mid-point of the 'cube' edges.
This taxon: Quadrum with one cycle larger than the other.
Morphology:
LITHS: nannolith-radiate, asymmetric, quadrate, CA: closed, CROSS-POLARS: T-prominent, |
Lith size: 4->5µm; Segments: 4->4; Data source notes: illustrated specimens |
Geological Range:
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Danian stage). Data source: Lees & Bown 2005 - consistently present to end Cret
First occurrence (base): within Late Maastrichtian Substage (66.04-69.91Ma, base in Maastrichtian stage). Data source: Burnett 1998
Plot of occurrence data:
Burnett, J. A. (1997c). New species and new combinations of Cretaceous nannofossils and a note on the origin of Petrarhabdus (Deflandre) Wise & Wind. Journal of Nannoplankton Research. 19(2): 133-146. gs V O Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gs OReferences:
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Quadrum bengalensis compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 29-3-2023
Short stables page link: https://mikrotax.org/Nannotax3/index.php?id=10967 Go to Archive.is to create a permanent copy of this page - citation notes |
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