Distinguishing features: Large, with thickened, dome-like distal shield; central area filled by a plug.
Farinacci & Howe catalog pages: R. magniscutum *
Morphology: Large, elliptical reticulofenestrids with a thickened, dome-like distal shield and central area filled with a plug.
Differentiation: Similar to other species of the Reticulofenestra bisecta group but with an elevated, dome-like distal shield, which is therefore highly birefringent (orange) in XPL and frequently seen in side view (Pl. 2, figs 41–44). [Bown & Newsam 2016]
Size: Holotype L = 8.5μm (Paratype L = 9.0μm). Side view coccolith height ~6.5μm.
|Tags||LITHS: placolith, elliptical, CA: ca_conjunct, grill, |
CSPH: equant, monomorphic, CROSS-POLARS: rim-unicyclic, R-prominent,
|Metrics||Lith size: 8->12µm;|
Notes: We have observed this species from a short stratigraphic interval in the middle Eocene (Subzone NP15a-lower Zone NP16), in an interval that predates the common occurrence of other members of the Reticulofenestra bisecta group by around 6 m.y. The species is very rare and so tracing the relationship between R. magniscutum and R. bisecta has not been possible. [Bown & Newsam 2016]
Last occurrence (top): within NP16 zone (40.40-42.87Ma, top in Bartonian stage). Data source: Bown & Newsam 2016
First occurrence (base): within NP15a subzone (45.49-46.29Ma, base in Lutetian stage). Data source: Bown & Newsam 2016
Plot of occurrence data:
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