Type Species

Discoaster brouweri Tan Sin Hok, 1927


Eu-discoaster Tan Sin Hok, 1927

Helio-discoaster Tan Sin Hok, 1927

Hemi-discoaster, Tan Sin Hok, 1927

Asterolithes Sujowski, 1931

Gyrodiscoaster Stradner, 1961

Agalmatoaster (Gemminiodicoaster) Prins, 1971

Radiodiscoaster (Curvidiscoaster) Prins, 1971

Truncodiscoaster Prins, 1971

Turbodiscoaster Prins, 1971


Stellate, rosette shape or discoidal nannolith often concave-convex.

The segments are non-birefringent in plan view.

The inner end of the segments may form distal and proximal processes.

The segments entirely or partly join each other.

The termination of segments can be simple, bifurcated or twisted.

The ridges and depression or other ornamentations may be present on the segments.

The two major groups can be identified [each group can be further subdivided]:

Rosette-shaped discoasters, having segments joined each other almost entirely their length.

Stellate discoasters, having segments only partly joined each other, leaving a distinct free length of segments.


The species of Discoaster are identified based on the following main criteria:

The number of segments, length of the segment, termination of segments and the presence or absence of nodes.

The diameter of the central area, the central area ornamentation

The ratio of the central area to free length of segments.

The shape of inter-segments areas.


Prins, B., (1971): Speculations on relations, evolution and stratigraphic distribution of discoasters. In, Farinacci, A. (ed.) - Proceedings of the Second Planktonic Conference Roma 1970. Edizioni Tecnoscienza, Rome 2: 1017-1037.

Stradner, H., (1961): Vorkommen von Nannofossilien im Mesozoikum und Alttertiär. - Erdoel-Zeitschrift. 77(3): 77-88.

Sujkowski, Z., (1931): Étude pétrographique de Crétacé de Pologne. - Sprawozdania Polskiego instytutu geologicznego. 6: 485-628.

Tan Sin Hok, (1927): Discoasteridae incertae sedis. - Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen. Sect Sci, 30: 411-419.