Rattrayella simbirskiana from Simbirsk, Russia. Single example on the slide, mounted with the rim upwards towards the coverslip (underside view). 8 ocelli. Prepared by William Allott Firth. 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. 59 images stacked in Zerene (Pmax).
Rattrayella simbirskiana (presumably). Rattrayella simbirskiana (Grunow) Hanna 1934. Published in: Hanna, G.D. (1934). Additional notes on diatoms from the Cretaceous of California. Journal of Paleontology 8: 352-355. Page 335. See also Sims, P.A. (2006). A revision of the genus Rattrayella De-Toni including a discussion on related genera. Diatom Research 21(1): 125-158. Homotypic synonyms; Eupodiscus simbirskianus Grunow 1887, Glyphodiscus simbirskianus (Grunow) Grunow 1888.