Two examples of Aulacodiscus rellae from Arroyo Hondo, Maria Madre Island, Mexico. Fossil marine material from the Miocene. Mounted in Naphrax and dated August 1969. Described on the slide as ‘small specimens’. Prepared by ECP Bone. Olympus BHB microscope using 450nm LED light. In addition to imaging the arrangement I also imaged them both individually at higher magnification. 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. Image stacks prepared in Zerene (Pmax).
Aulacodiscus rellae G.D.Hanna & Grant 1926. Published in (as A. rellæ): Hanna, G.D. & Grant, W.G. (1926). Expedition to the Revillagigedo Islands, Mexico, in 1925, II. Miocene marine diatoms from Maria Madre Island, Mexico. Proceedings of the California Academy of Sciences, series 4, 15(2): 115-[193]. [in English]. Page 128, Plate 13, Figures 5,6.