Nannotax Enabling nannofossil research

Description: This genus was described from the Eocene, but many authors, have ascribed Neogene specimens to it. Backman (1980) described them as coccoliths with a single shield composed of two cycles; a lower cycle of numerous steeply imbricate elements and an upper cycle of fewer tabular elements. In the LM these specimens have a Reticulofenestra-type extinction cross, but with a bright outer rim (in Reticulofenestra the shields are darker than the inner parts of the coccolith, since they are thinner). However, reticulofenestrid coccoliths which have lost most of their shields, leave central cores identical to “Pyrocyclus”. Also, “Pyrocyclus” coccoliths always occur with reticulofenestrids with central-areas of similar size, and shape. This suggests that the “Pyrocyclus” specimens are relict reticulofenestrid cores, or in some cases proto-coccolith rings.

Described “species” of Pyrocyclus:

• Pyrocyclus inversus Hay and Towe, 1962,
• Pyrocyclus hermosus Roth and Hay, 1967;
• Pyrocyclus orangensis (Bukry, 1971) Backman, 1980.

There is no obvious justification or value in using any of these species

Remarks: