Cyclicargolithus

Coccolithus floridanus Roth & Hay in Hay et al., 1967

Optical Properties: All components show inclined extinction lines and length-fast (-) elongation. The extinction angle , measured on the distal side, is typically about 9° on the distal shield and about 77° on the tube cycles.

Strictly circular placoliths exhibit single-tiered distal and proximal shields, a single distinct tube cycle, and a narrow and void central area.

Cyclicargolithus differs from other genera of Noelaerhabdaceae by being circular, having a distinct tube cycle and a narrow void central area.

The species of Cyclicargolithus are distinguished by their size in this study:

• The forms less than 6.0 μm are assigned to Cyclicargolithus floridanus (holotype is 3.6 μm),
• The forms between 6.0 μm and 10.5 μm are assigned to Cyclicargolithus neogammation (holotype is 10.0 μm)
• The forms greater than 10.5 μm are assigned to Cyclicargolithus abisectus (holotype is 10.5 μm).

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

Hay, W. W., Mohler, H. P., Roth, P. H., Schmidt, R. R. & Boudreaux, J. E. 1967. Calcareous nannoplankton zonation of the Cenozoic of the Gulf Coast and Caribbean-Antillean area, and transoceanic correlation. - Transactions of the Gulf-Coast Association of Geological Societies 17: 428-480.