Helicosphaera pteriga

Set number: 1274

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10µm

Helicosphaera pteryga, Middle Pleistocene, DSDP Leg 23 Site 229A, Red Sea

Final Epithet

Helicosphaera pteriga Varol, 2025

Basionym

Helicosphaera pteriga Varol, 2025

Diagnosis

A helicolith characterised by a Type III (Helicosphaera carteri type) blanket and a wing-like, expanded flange termination that extends nearly the entire length of the sinistral side of the helicolith. The proximal plate is featureless.

Etymology

Derived from the Greek pteryga, meaning “wing,” referring to the wing that extends nearly the entire length of the sinistral side of the helicolith

Description

Optical Properties: Helicosphaera pteryga exhibits inclined extinction angles of approximately 55° on the blanket on the distal side and displays length-fast (−) elongation

Remarks

Helicosphaera pteryga is distinguished from Helicosphaera burkei by its wing-like expanded flange termination, which extends almost the entire length of the sinistral side of the helicolith. In contrast, in Helicosphaera burkei, the wing is confined to the anterior end. Helicosphaera pteryga differs from Helicosphaeroides magnifica by its Type III blanket (Helicosphaera carteri type), in contrast to the Type I blanket (Helicosphaeroides ampliaperta type) found in the latter.

References

Varol, O. 2025. A practical guide to optical studies of calcareous nannofossils. Grzybowski Foundation Special Publication. 29: 1-222