Eukaryota platyrhethus

Set number: 2916

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Eukaryota platyrhethus, Late Aptian, Onshore Texas, USA

Set number: 2915

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Eukaryota platyrhethus, Late Aptian, Onshore Texas, USA

Set number: 2914

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Eukaryota platyrhethus, Early Cenomanian, Folkestone, England

Set number: 2913

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Eukaryota platyrhethus, Early Cenomanian, Folkestone, England

Set number: 2912

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Eukaryota platyrhethus, Early Cenomanian, Vergons, SE France

Set number: 2911

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Eukaryota platyrhethus, Early Cenomanian, Vergons, SE France

Set number: 2910

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Eukaryota platyrhethus, Late Aptian, Gargas, SE France

Set number: 2917

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Eukaryota platyrhethus, Late Cenomanian, Olini Creek, Colombia

Final Epithet

Eukaryota platyrhethus Hill, 1976

Basionym

Chiastozygus platyrhethus Hill, 1976

Optical Properties

In plan view under crossed polars, the walls remain in constant extinction, reflecting the orientation of the optic axis (c‑axis) perpendicular to the microscope stage. In contrast, the diagonal cross displays first‑order white interference colours, highlighting its differing crystallographic orientation.

Remarks

Species of Chiastozygus are constructed with a double wall enclosing a symmetrical diagonal cross that supports a distal process. Each arm of the diagonal cross is divided into two distinct halves, contributing to the characteristic internal architecture of the genus.

References

Hill, M. E. 1976. Lower Cretaceous calcareous nannofossils from Texas and Oklahoma. Palaeontographica Abteilung B Palaeophytologie. 156: 103-179.