Stictodiscus truani from Hayti (Haiti). Single example on the slide. Unknown maker. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece (11mm of spacer to the camera removed – this is a big diatom). Monochrome converted Nikon d850 camera. 54 images stacked in Zerene (Pmax).
Published in: Truan y Luard, A. & Witt, O.N. (1888). Die Diatomaceen der Polycystinenkreide von Jérémie in Hayti Westindien. pp. [1]–38, incl. 7 pls [I-VII]. Berlin: Verlag von R. Friedländer & Sohn. Page 19 and Plate IV, figures 23 and 24. This slide has some issues, and these are most obvious in the 12-4 o’clock part of the diatom. There is no makers name, but I have a few by this maker (for example here). Like that one, this is quite high contast and has a very specific look about it.