Rutilaria lanceolata from Oamaru, New Zealand. Single example on the slide. Some of the red dye from the ring has bled into the diatom. Prepared by Thomas Edward Doeg. 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. 19 images stacked in Zerene.
Rutilaria lanceolata Grove & Sturt, 1886. Published in: Grove, E. & Sturt, G. (1886). On a fossil marine Diatomaceous deposit from Oamaru, Otago, New Zealand. Part I. Journal of the Quekett Microscopical Club, Series 2 2(16): 321–330, plates 18–19. Page 324, Plate 18, Figure 6.
This one is 230µm long, which puts it at the long end of the size range – 125-235µm, from: Ross, R. (1995). A revision of Rutilaria Greville (Bacillariophyta). Bulletin of the Natural History Museum, London, Botany 25(1): 1-93, 20 pls. In particular, Pages 40,41, Figures 49,50, Plate XIV.