Craspedodiscus rhombicus from Monterey, California, USA. Single example on the slide. Dated 1912. Prepared by JA Long. 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. 54 images stacked in Zerene (Pmax). Very ‘3D’ given its small size. Hat shaped with a raised dome area in the middle and flat, rhomboid rim.
Craspedodiscus rhombicus Grunow in Schmidt et al., 1881. Original description: Schmidt, A. (1881). Atlas der Diatomaceen-kunde. Aschersleben, Commissions-Verlag Von Ludwig Siever’s Buchandlung, Series II(Heft 17-18): pls. 65-72. Plate 66, Figure 13.