Lepidodiscus elegans from Ananino, Simbirsk, Russia. Single example on the slide, and it has moved to the edge of the ring around the diatom. Mounted in Styrax and dated 5/4/1912. Yellowing of the mountant, although not as bad near the middle of the slide. No makers name, but I think it could be by the same person who made this slide. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.40 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. 11mm removed from the tube to the camera to increase the field of view. Monochrome converted Nikon d850 camera. 31 images stacked in Zerene (Pmax).
Lepidodiscus elegans Witt 1886. Published in: Witt, O.N. (1886 ‘1885’). Ueber den Polierschiefer von Archangelsk-Kurojedowo im Gouv. Simbirsk. Verhandlungen der Russisch-kaiserlichen Mineralogischen Gesellschaft zu St. Petersburg, Series II 22: 137-177, pls. VI-XII. Page 163, Plate 7, Figure 6.
Also see: Witkowski, J., Harwood, D.M. (2010). Observations on two species of Lepidodiscus Witt (Bacillariophyta) from Devon Island, Canadian High Arctic. Micropaleontology 56: 587-597.
See for more information: https://diatomimaging.com/lepidodiscus-elegans-arthur-cottam/