Two examples of Triceratium crenulatum from Oamaru, New Zealand. Cracked coverslip. Very orange mountant. Prepared by JA Long. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo NA 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 66 images stacked in Zerene (Pmax). Full disclosure, the larger one on the left had moved from its original position, as seen by lines in some of the individual frames for the stack. I have re-positioned it for this image.
Triceratium crenulatum Grove & Sturt 1887. Published in: Grove, E. & Sturt, G. (1887). On a fossil marine diatomaceous deposit from Oamaru, Otago, New Zealand. Part II. Journal of the Quekett Microscopical Club, Series 2, 3 (17). Journal of the Quekett Microscopical Club, Series 2 3(17): 7-12, 2 pls. Page 7, Plate II, Figure 3. This name is currently regarded as a synonym of Sheshukovia crenulata (Grove & Sturt) Glezer 1984. Published in: Glezer, Z.I. (1984). Znachenie issledovanij po sistematike diatomovych vodoroslej dlia biostrtigrafii i paleogeographii [The importance of research about systematics of diatom algae for biostratigraphy and paleogeography]. Ezhegodnik Vsesoyuznogo Paleontologicheskogo Obshchestva 27: 284-298, 1 figure, 1 table. [in Russian]. Page 293.