Nannotax Enabling nannofossil research

Description: Species of Calcidiscus producing circular coccoliths with open central-area, 7-10μm.

Remarks: Not always separated from C. leptoporus. Miocene forms often have a bicyclic proximal shield, in Pliocene forms a coarse grill is often visible in central opening. Larger forms (>10µm) are separated as C. macintyrei, possibly evolves into C. quadriperforatus.

Range: NN4 to 19.

Variants;

• C. leptoporus ssp centrovalis (Stradner and Fuchs, 1980) Perch-Nielsen, 1984 - similar to C. tropicus but sub-circular;
• C. carlae (Lehotayova and Priewalder, 1978) Janin, 1992 [Cycloperfolithus] - Paratethyan form, with fine grill in central-area, and bicyclic proximal shield.