Distinguishing features: Narrowly-elliptical, central area with numerous (18–22) radiating bars
Farinacci & Howe catalog pages: N. radiatus *
Morphology: Narrowly-elliptical murolith coccolith with a low birefringence, unicyclic rim image and central area with numerous (around 18–22) radiating bars.
Description: The rim shows relatively low birefringence in XPL as do the central area bars. Some specimens have outlines approaching rhomboidal.
Remarks: The rhomboidal outline and stratigraphic position close to the extinction of Neococcolithes dubius and first appearance of Isthmolithus recurvus suggest that this may be a transitional species between the two genera.
Differentiation: Distinguished from most other species of Neococcolithes, which have diagonal crossbars, by the more numerous central area bars. [Bown & Newsam 2017]
Size: Holotype L = 7.6μm (Paratype L = 6.4μm).
|Tags||LITHS: murolith, elliptical, CA: ca_disjunct, grill, CROSS-POLARS: rim-unicyclic, V-prominent,|
|Metrics||Lith size: 5->8µm; |
Data source notes: lith size from OD and slightly extended
Last occurrence (top): within NP17 zone (37.32-40.40Ma, top in Priabonian stage). Data source: Bown & Newsam 2017
First occurrence (base): within NP17 zone (37.32-40.40Ma, base in Bartonian stage). Data source: Bown & Newsam 2017
Plot of occurrence data:
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