Stictodiscus serpentinus from Joe’s River, Barbados. Single example on the slide, mounted upside down (with the rim facing the coverslip). Prepared by JA Long and mounted in Hyrax. 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. 37 images stacked in Zerene (Pmax).
Synonymised names: Cladogramma serpentinum (Truan & Witt) Kuntze, 1898 · uncertain > unassessed. Original description: Truan y Luard, A. & Witt, O.N. (1888). Die Diatomaceen der Polycystinenkreide von Jeremie in Hayti, Westindien. Friedlander et Sohn, Berlin., 24 pp., 7 pls. page(s): p. 21; pl. 6, fig. 1, 4.
Stictodiscus serpentinus also appears in Schmidt’s Atlas, Plate 449, Figures 2 and 3. I did find one other image online labelled as S. serpentinus, but it did not match this one (or have the characteristic ‘serpent like’ structures in the central portion), so I will stick with confirmation of the ID from Schmidt’s Atlas for now.