Type Species

Dictyococcites danicus Black, 1967

Diagnosis

Elliptical to circular reiculofenestrid having unicycle distal and proximal shields and a tube cycle. The central area is covered by a plug distally and a central mesh proximally. The entire coccolith is birefringent under polarised light.

Description

The plug may or may not cover the entire central area distally. Under the light microscope, the tube cycle and the plug cannot be distinguished from each other.

Elliptical Groups

Dictyococcites stavensis Group

Plug completely closed the central area

  • Dictyococcites burnsii Varol, in prep.; >14.0µm
  • Dictyococcites stavensis (Levin & Joerger, 1967) Varol, 1989; 10.0 - 14.0µm
  • Dictyococcites bisectus (Hay, Mohler & Wade, 1966) Bukry & Percival, 1971; 8.0 - 10.0µm
  • Dictyococcites scissurus (Hay, Mohler and Wade, 1966) Varol, 2025; 6.0 - 8.0µm
  • Dictyococcites antarcticus Haq, 1976; 4.0 - 6.0µm
  • Dictyococcites productellus (Bukry, 1975) Backman, 1980; <4.0µm

Dictyococcites pseudolockeri Group

Plug partly closed the central area

  • Dictyococcites pseudolockeri (Jurasova, 1974) Varol, n. comb.; 10.0 - 14.0µm
  • Dictyococcites filewiczii (Wise & Wiegand in Wise, 1983) de Kaenel, in de Kaenel & Londeix 2014; 8.0 - 10.0µm

Circular Group

Dictyococcites erbae Group

Plug completely closed the central area

  • Dictyococcites erbae (Fornaciari et al., 2010) Varol, comb. nov.; 4.0 - 10.0µm
Remarks

Dictyococcites differs from Reticulofenestra Hay, Mohler & Wade (1966), Cribrocentrum Perch-Nielsen (1971) and Cyclicargolithus Bukry (1971) by having a distal plug. It is further differentiated from Reticulofenestra and Cyclicargolithus by having a birefringent permanent central mesh. The species of Dicyococcites are primarily identified based on their shape and size. The ratio of pelaga to the central area and complete or incomplete plug are also used for speciations.

References

Bukry, D., (1971): Cenozoic calcareous nannofossils from the Pacific Ocean. - San Diego Society of Natural History Transactions. 16: 303-327.

Hay, W. W., Mohler, H. P. & Wade, M. E., (1966): Calcareous nannofossils from Nal'chik (northwest Caucasus). - Eclogae Geologicae Helvetiae. 59: 379-399.

Levin, H. L. & Joerger, A. P., (1967): Calcareous nannoplankton from the Tertiary of Alabama. - Micropaleontology. 13(2): 163-182.

Perch-Nielsen, K., (1971): Elektronenmikroskopische untersuchungen an Coccolithen und verwandten Formen aus dem Eozan von Danemark. - Biologiske Skrifter, Kongelige Danske Videnskabernes Selskab. 18(3): 1-76.