Stauroneis fulmen var. capitata from Ongaroto Valley, New Zealand. Single example on the slide, and I think this is an underside view with the rim upwards towards the coverslip. Prepared by JA Long. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 57 images stacked in Zerene (Pmax).
Stauroneis fulmen var. capitata Heiden in Schmidt et al., 1903. Original description: Schmidt, A. (1903). Atlas der Diatomaceen-kunde. Leipzig. O.R. Reisland, Series VI(Heft 61): pls. 241-244. Plate 241, Figures 6,7.