Distinguishing features: Medium sized (5-7 µm) with narrow shields / wide central area. In xpl the inner rim cycle is usually slightly narrower than the outer rim cycle
Taxonomy:
Farinacci & Howe catalog pages: T. bellii *
Distinguishing features: Medium sized (5-7 µm) with narrow shields / wide central area. In xpl the inner rim cycle is usually slightly narrower than the outer rim cycle
Morphology: Medium sized (5-7 µm) Tubodiscus with narrow shields and wide, open, central area. The rim image is bicyclic in XPL and the two cycles have contrasting birefringence, the inner cycle being distinctly bright. The inner cycle is usually slightly narrower than the outer.
The shields and individual cycles are narrower than those of other tubodiscids.
Tags | LITHS: placolith, elliptical, CA: vacant, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent, |
Metrics | Lith size: 5->7µm; Data source notes: original description +/-0.5 µm |
Geological Range:
Last occurrence (top): within Berriasian Stage (139.39-145.01Ma, top in Berriasian stage). Data source: Bown 2005
First occurrence (base): within Berriasian Stage (139.39-145.01Ma, base in Berriasian stage). Data source: Bown 2005
Plot of occurrence data:
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Tubodiscus bellii compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 27-1-2021
Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=11273 Go to Archive.is to create a permanent copy of this page - citation notes |