Stictodiscus hüttlingerianus from Hayti (Haiti). Single example on the slide. Section missing, and issues with the mountant/adhesive. 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. 24 images stacked in Zerene (Pmax). Note, the issues with the coverslip adhesive have had a benefit here, as it makes the texture on the surface of the frustule more visible in areas where it has not stuck properly.
I recently acquired about 60 slides by this maker, so if you want to see others by them, search for AAAAA in the Search option at the top of the page, and I’ll include this in each of the pages for them.