Cerataulus deflandrei from Kamischev, USSR. Single example on the slide, mounted with the underside upwards towards the coverslip. Metal spacers for the coverslip, visible from the back of the slide. Mounted in Styrax/Aroclor, and dated September 1981. Prepared by Richard Gosden. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 81 images stacked in Zerene (Pmax).
Cerataulus deflandrei Cheneviere, 1934. Published in: Chenevière, E. (1934). Sur un dépôt fossile marin à diatomées situé à Kamischev (Russie centrale). Bulletin de la Société Française de Microscopie, 3(3): 103-107, pls 5-8. Page 105, Plate 3(7), Figure 3.
See also: Patricia A. Sims (2006) A revision of the genus Rattrayella De-Toni including a discussion on related genera, Diatom Research, 21:1, 125-158, DOI:10.1080/0269249X.2006.9705656
From Sims (2006);
“The triangular species identified as Cerataulus deflandrei by Chenevikre (Figs 114-121) from the early Eocene of Kamischev, Russia is also included and clearly does not belong within Cerataulus, a genus with loculate areolae and submarginal rimoportulae extending externally as spines. It too has characters in common with Rattrayella and Auliscus but differs from Rattrayella by having large ocelli, a deep mantle and the absence of dimpling on the valve face and from Auliscus by the lack of a hyaline central area, in having marginal ocelli that lie at a distinct angle to the valve face and most significantly a triangular valve outline. Again, this species is difficult to place in a genus.”