Calcidiscus tropicus

Cyclococcolithus tropicus Kamptner, 1955

Large [>10.0µm] circular species of Calcidiscus having a relatively wide central opening. The central area is without structure. The proximal shield is strongly birefringent and almost equal to the distal shield in diameter.

Calcidiscus tropicus differs from Calcidiscus premacintyrei Theodoridis (1984) by being circular. It is distinguished from Calcidiscus leptoporus (Murray & Blackman 1898) Loeblich & Tappan (1978) by being large and having an open central area. It is identified from Calcidiscus macintyrei (Bukry & Bramlette, 1969) Loeblich & Tappan (1978) by having about equal diameter shields and a relatively wider central opening.

Bukry, D. & Bramlette, M. N., (1969): Some new and stratigraphically useful calcareous nannofossils of the Cenozoic. - Tulane Studies in Geology. 7: 131-142.

Kamptner, E., (1955). Fossile Coccolithineen-Skelettreste aus Insulinde. Eine mikropaläontologische Untersuchung. - Verhandelingen der Koninklijke Nederlandse Akademie van Wetenschappen, Afdeling Natuurkunde. ser 2, 50: 1-105.

Loeblich, A. R. & Tappan, H., (1978): The coccolithophorid genus Calcidiscus Kamptner and its synonyms. - Journal of Paleontology. 52: 1390-1392.

Murray, G. & Blackman, V. H., (1898): On the nature of the Coccospheres and Rhabdospheres. - Philosophical Transactions of the Royal Society of London B: Biological Sciences. 190(1): 427-441.

Theodoridis, S., (1984): Calcareous nannofossil biostratigraphy of the Miocene and revision of the helicoliths and discoasters. - Utrecht Micropaleontological Bulletin. 32: 1-271.

Varol, O., (1989): Calcareous nannofossil study of the central and western Solomon Islands. - Circum-Pacific Council for Energy and Mineral Resources Earth Sciences. 239-268.