Discolithus fenestratus Deflandre & Fert, 1954
The elliptical placolith possesses a single-layer distal shield, a double-layer proximal shield, and a central area covered by a porous plate on the distal side. Under cross polarised light, the tube cycle and the inner layer of the proximal shield are birefringent.
Clausicoccus differs from Coccolithus Schwarz (1894), Cruciplacolithus Hay & Mohler in Hay et al. (1967), and Sullivania Varol (1992) by possessing a porous plate in the central area. Species of Clausicoccus are distinguished based on overall size, the arrangement of pores within complete cycles of rings, the presence or absence of crossbars, and the relative size of the central area.
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.
Prins, B. 1979. Notes on nannology 1. Clausicoccus, a new genus of fossil Coccolithophorids. INA Newsletter 1: N2-N4.
Haeckel, E. 1894. Systematische Phylogenie der Protisten und Pflanzen. Reimer, Berlin.
Varol, O. 1992b. Sullivania a new genus of Palaeogene coccoliths. Journal of Micropalaeontology 11: 141-150.