Set number: 347

  • Helicosphaera africanus 2386 1
  • Helicosphaera africanus 2387 2
  • Helicosphaera bowmanii 2390 3
  • Helicosphaera bowmanii 2388 4
    10µm
Helicosphaeroides africanus, Late Oligocene, Angola, West Africa

Set number: 348

  • Helicosphaera bowmanii 2405 1
  • Helicosphaera bowmanii 2404 2
  • Helicosphaera bowmanii 2402 3
  • Helicosphaera bowmanii 2403 4
    10µm
Helicosphaeroides africanus, Late Oligocene, Angola, West Africa

Set number: 351

  • Helicosphaera bowmanii 2439 1
  • Helicosphaera bowmanii 2438 2
  • Helicosphaera bowmanii 2436 3
  • Helicosphaera bowmanii 2437 4
    10µm
Helicosphaeroides africanus, Late Oligocene, Angola, West Africa
Final Epithet
Helicosphaeroides africanus Varol, in prep.
Basionym

Helicosphaeroides africanus Varol, in prep.

Diagnosis

Species of Helicosphaeroides has a symmetrical blanket confined to the central area (not extending to the periphery of the flange) (Type I, Helicosphaeroides ampliaperta Type) blanket, a flush flange termination and a relatively large central opening spanned by the delicate conjunct inverse bar.

Etymology

After African continent

Description

Helicolith has a Type I (Helicosphaeroides ampliaperta type) blanket, a flush flange termination and a relatively large central opening spanned by the delicate conjunct inverse bar with a split in the middle.

Remarks

Helicosphaeroides africanus differs from Helicosphaeroides vedderi (Bukry,1981) Varol, n. comb. by having an inverse conjunct bar with a split in the middle whereas the latter has an oblique conjunct bar without a split. Moreover, the oblique bar of Helicosphaera vedderi is non-birefringent at 0° under polarised light.

References

Bukry, D., 1981b. Pacific coast coccolith stratigraphy between Point Conception and Cabo Orientes, Deep Sea Drilling Project Leg 63. Initial Reports of the Deep Sea Drilling Project 63, 445-471.