Ilselithina fusa

Set number: 454

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10µm

Ilselithina fusa, Late Oligocene, DSDP Leg 25, Site 242, Mozambique Channel (Davie Ridge), Indian Ocean

Set number: 455

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10µm

Ilselithina fusa, Late Oligocene, DSDP Leg 25, Site 242, Mozambique Channel (Davie Ridge), Indian Ocean

Set number: 1656

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10µm

DSDP Leg 25, Site 242, Mozambique Channel (Davie Ridge), Indian Ocean

Final Epithet

Ilselithina fusa Roth, 1970

Basionym

Ilselithina fusa Roth, 1970

Description

The single-cycle shield is made up of about 16 segments which are non-birefringent on a plan view in polarised light. The inner ends of every other segment produce tulip-like about 8 distal processes. Distal processes are distended at the base and birefringent in plan view in polarised light. The entire coccolith is birefringent on a side view.

Remarks

Ilselithina fusa is distinguished from Ilselithina iris Stradner in Stradner and Adamiker (1966) by lacking slits between the shield segments.

References

Roth, P. H., (1970): Oligocene calcareous nannoplankton biostratigraphy. - Eclogae Geologicae Helvetiae. 63: 799-881.

Stradner, H. & Adamiker, D., (1966): Nannofossilien aus Bohrkernen und ihre elektronenmikroskopische Bearbeitung. - Erdoel-Erdgas Zeitschrift. 82: 330-341.

Taxonomy

Ilselithina

Ilselithina fusa

Biostratigraphy

Stratigraphic Range

Chattian - Aquitanian

Age (Ma)

27.25 - 21.90

Holotype

Ilselithina fusa Roth, 1970

Oligocene

The Lone Star Cement Company Quarry, St. Stephens, Alabama, U.S.A