Variant: Discoaster astellaris is regarded here as a variant of Discoaster bellus.
I.e. It is a subjective junior synonym, but some workers many find it useful for some studies (e.g. experienced biostratigraphers working with abundant, well preserved material), but for most purposes differentiating it is not reccomended. Please do use the comments section at the bottom of this page if you wish to discuss this interpretation
Taxonomy:
Distinguishing features:
Parent taxon (Discoaster bellus): Symmetric 5-rayed species with simple ray tips
This taxon: Like D. bellus but asymmetric
Farinacci & Howe catalog pages: D. astellaris *
Morphology:
LITHS: nannolith-radiate, star-shaped, CROSS-POLARS: 1ou, V-prominent, |
Lith size: 0->0µm; Segments: 5->5; |
Geological Range:
Notes: Range similar to that of regular D. bellus. Blair et al. (2017) report that it is too rare in the early part of its range to be of any use but that it becomes consistently present in upper NN10 and that its LAD in lower NN11 is useful.
Last occurrence (top): in lower part of NN11 zone (20% up, 7.8Ma, in Tortonian stage). Data source: Blair et al 2017
First occurrence (base): within NN8 zone (10.55-10.89Ma, base in Tortonian stage). Data source: Blair et al 2017
Plot of occurrence data:
Blair, S. A., Bergen, J. A., de Kaenel, E., Browning, E. & Boesiger, T. M. (2017). Upper Miocene-Lower Pliocene taxonomy and stratigraphy in the circum North Atlantic Basin: radiation and extinction of Amauroliths, Ceratoliths and the D. quinqueramus lineage. Journal of Nannoplankton Research. 37(2-3): 113-144. gs OReferences:
Discoaster astellaris compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 11-9-2024
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1589 Go to Archive.is to create a permanent copy of this page - citation notes |
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