A strew slide labelled as Cyclotella meneghiniana from Seville, Spain. Fossil freshwater material. Look to be various different species on the slide. Prepared by Eduard Thum, and sold by C Baker. Olympus BHB microscope using 450nm LED light. As well as the strew I imaged one using the 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. 17 images stacked in Zerene (Pmax).
Cyclotella meneghiniana Kützing, 1844. Published in: Kützing, F.T. (1844). Die Kieselschaligen Bacillarien oder Diatomeen. pp. [i-vii], [1]-152, pls 1-30. Nordhausen: zu finden bei W. Köhne. Page 50, Plate 30, Figure 68. This name is currently regarded as a synonym of Stephanocyclus meneghinianus (Kützing) Kulikovskiy, Genkal & Kociolek, 2022. Published in: Kulikovskiy, M., Genkal, S., Maltsev, Y., Glushchenko, A., Kuznetsova, I., Kapustin, D., Gusev, E., Martynenko, N. & Kociolek, J.P. (2022). Resurrection of the diatom genus Stephanocyclus (Coscinodiscophyceae: Stephanodiscaceae) on the basis of an integrated molecular and morphological approach. Fottea 22(2): 181-191. Page 189 (as ‘meneghiniana‘).
However this one does not look particularly like the images I have seen for C. meneghiniana, so I will leave it as Cyclotella sp. for now.