Actinodiscus sp. (I think this might be A. corolla) from Forrester’s Hill, Oamaru, New Zealand. Single example on the slide. Fossil marine material. Prepared in Naphrax and dated 14/10/[19]70. Prepared by Richard Gosden. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 36 images stacked in Zerene (Pmax).
Actinodiscus corolla (J. Brun) R. Ross & P.A. Sims, 2000. Original name: Craspedoporus corolla Brun in Brun & Tempère, 1889. Original description: (of Craspedoporus corolla Brun in Brun & Tempère, 1889) Brun, J. & Tempère, J. (1889). Diatomées Fossiles du Japon. Espèces marines et nouvelles des calcaires argileux de Sendaï et de Yedo. Mémoires de la Société de Physique et d’Histoire Naturelle de Genève, 30(9): 75 pp., 9 pls. Page 34, Plate 4, Figure 4.
See also: Ross, R. & Sims, P.A. (2000). A revision of Actinodiscus Greville, Craspedoporus Greville and related genera (Eupodiscaceae). Diatom Research, 15(2): 285-347. Pages 298-302. This is what I used to settle on A. corolla.