Actinoptychus sp. from Oamaru, New Zealand. Single example on the slide. Mounted in Hyrax and dated June 1935. Prepared by Samuel Henry Meakin. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 33 images stacked in Zerene (Pmax).
Not sure as to species. Features similar to a few different ones, but nothing which I can pin down to a specific species. Maybe Actinoptychus splendens var. glabrata based on Päule Heck’s book, Die fossilen Diatomeen Oamarus (Neuseeland) aus den Sammlungen von Bernard Hartley und Nigel Charles. Figure 43, Page 13.