Discoaster bergenii


Ancestry: Coccolithophores -> Discoasterales -> Discoasteraceae -> Discoaster -> D. quinqueramus group -> Discoaster bergenii
Sister taxa: D. quinqueramus, D. berggrenii, D. bergenii,

Short diagnosis: Like D. berggrenii but central-area very wide (>2x free ray length)/rays stubby.


Taxonomy:

Citation: Discoaster bergenii Knuttel, Russell and Firth, 1989
Rank: Species

Farinacci & Howe catalog pages: Discoaster bergenii *

Short diagnosis: Like D. berggrenii but central-area very wide (>2x free ray length)/rays stubby.


Morphology remarks: Like D. quinqueramus but central-area very wide (>2x free ray length).

Search data:
TagsLITHS: nannolith-radiate, star-shaped, RIM: free-rays-short, PROCESS: boss, boss-proximal, distal-star,
CSPH: not known, V-UNITS: all, R-UNITS: none, DETAILS: 1ou,
MetricsLith size: 5->10┬Ám; Segments: 5->5;
Sources: size from OD & illustrated specs
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Notes: D. bergenii, D. bergrennii and D. quinqueramus apparently form an anagenetic lineage, with central area size deceasing and free ray length increasing. Distinguishing them is useful for determining position within the early part of zone NN11.
Last occurrence (top): within NN11a subzone (7.42-8.29Ma, top in Tortonian stage). Data source: Young 1998
First occurrence (base): at base of NN11 zone (0% up, 8.3Ma, in Tortonian stage). Data source: Young 1998

Plot of occurrence data:

References:

Knuttel, S.; Russell, M.D. & Firth, J.V., (1989). Neogene calcareous nannofossils from Leg 105: Implications for Pleistocene paleoceanographic trends. Proceedings of the Ocean Drilling Program. Scientific Results, 105: 245-262.

Young, J.R., (1998). Neogene. In: Bown, P.R. (Editor), Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publications Series. Chapman & Hall, London, pp. 225-265.


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Discoaster bergenii compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 19-10-2017

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Mike Styzen (Noble Energy, US)
Discoaster quinqueramus/berggrenii plexus: I posted a document with some sketches from the original Gulf Coast Taxonomic Equivalency Project of this group in the forum.
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