Davidbukrya clemencesalleyae

Varol, 2023 Apr 22, 2023

Set number: 3883

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10µm

Davidbukrya clemencesalleyae, Late Paleocene, DSDP Leg 25, Site 245, Mozambique Channel (Davie Ridge), Indian Ocean

Holotype, in the mobile mount.

Set number: 3884

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10µm

Davidbukrya clemencesalleyae, Late Paleocene, DSDP Leg 25, Site 245, Mozambique Channel (Davie Ridge), Indian Ocean

Set number: 3882

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10µm

Davidbukrya clemencesalleyae, Late Paleocene, DSDP Leg 25, Site 245, Mozambique Channel (Davie Ridge), Indian Ocean

Set number: 3881

1
2
3
4
5
6
7
8

10µm

Davidbukrya clemencesalleyae, Late Paleocene, DSDP Leg 25, Site 245, Mozambique Channel (Davie Ridge), Indian Ocean

Final Epithet

Davidbukrya clemencesalleyae Varol, 2023

Basionym

Davidbukrya clemencesalleyae Varol, 2023

Diagnosis

Gigantic (14.0–17.0 μm) species of Davidbukrya comprising a non-birefringent disc bulging around the solid birefringent tube cycle.

Etymology

In honour of my granddaughter, Clémence Salley, Qatar.

Dimensions Of Holotype

The diameter of the disc: 15.30 μm (measured in cross-polarised light), the thickness of the disc: 6.23 μm, the diameter of the tube cycle: 2.12 μm (measured in plan view)

Description

The sutures between segments are not visible where the disc bulges around the narrow tube cycle. A shallow depression is present at the proximal end of the narrow canal (at the less convex sides). The number of segments constructing the disc is between 26 and 40, and they are joined along almost their entire length.

Optical Properties

The disc is birefringent in the side view in cross-polarised light, producing a yellowish interference colour. The extinction lines are complicated to distinguish confidently. The inclined extinction lines on the disc are dextrogyre on the distal side but laevogyre on the proximal side. In contrast, the extinction lines on the tube cycle are laevogyre on the distal side but dextrogyre on the proximal side. When using a gypsum plate, the blue interference colours correspond to the horizontal axis on the distal side (Plate 22, Figs. 5,13 in Varol, 2023). In contrast, the blue interference colours correspond to the vertical axis on the proximal side (Plate 22, Figs. 6,14 in Varol, 2023).

Remarks

Davidbukrya clemencesalleyae is easily distinguished from Davidbukrya claracirculus by having a solid tube cycle, whereas the latter species has a hollow tube cycle. Davidbukrya clemencesalleyae is distinguished from Candeodiscoaster protomultiradiatus by lacking a disjunct hollow proximal structure around the tube cycle. Davidbukrya clemencesalleyae differs from Davidbukrya perchnielseniae by having a disc bulging around the tube cycle and a size >14.0 μm.

References

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