Discoaster bordii

Set number: 609

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10µm

Discoaster bordii, Late Paleocene, Santos Basin, Brazil

Set number: 603

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10µm

Discoaster bordii, Thanetian, DSDP Leg 39, Sites 354, Ceará Rise, North Atlantic Ocean

Set number: 604

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10µm

Discoaster bordii, Late Paleocene, DSDP Leg 39, Sites 354, Ceará Rise, North Atlantic Ocean

Final Epithet

Discoaster bordii Varol, 2023

Basionym

Discoaster bordii Varol, 2023

Diagnosis

A large (8.0–13.0 μm) circular species of Discoaster with a non-birefringent lenticular disc and a solid non-birefringent, disjunct proximal structure.

Etymology

In honour of nannofossil specialist Dr D Bord, Ellington Geological Services, Houston, Texas, USA.

Dimensions Of Holotype

The diameter of the disc: 12.11μm, the thickness of the disc: 4.25μm, the diameter of the proximal structure: 4.02μm, the height of the proximal structure: 2.31μm; all measured in phase-contrast.

Description

The number of segments that make up the disc is between 19 and 32, and they are joined along most of their length. In the side view, the relatively narrow proximal structure is often parallel-sided and has a slightly concave proximal end.

Remarks

Discoaster bordii is distinguished from Discoaster multiradiatus by having a solid, discrete proximal structure. Discoaster bordii differs from Candeodiscoaster protomultiradiatus in that it has a solid proximal structure and lacks a tube cycle.

References

Varol, O. 2023. New paleocene calcareous nannofossils: Carlamuelleria, Davidbukrya, Mauriceblackia, Noelia and Senelia. Marine Micropaleontology. 180: 1-41.