An arrangement of 16 Aulacodiscus sp. from Oamaru, New Zealand. Prepared by Ernest Wainright in May 1942. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, brightfield lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. Image stacks prepared in Zerene (Pmax).
Identifications from ‘Oamaru Diatoms’ by Desikachary and Sreelatha.
Aulacodiscus rattrayii (var. rattrayii). 2 processes. 57 images stacked.
Aulacodiscus barbadensis. 4 processes. 36 images stacked.
Aulacodiscus angulatus var. plana. 9 processes. 11mm spacer removed from the tube the camera to allow it to fit the image. 79 images stacked. Interestingly this is much bigger than the size range given in the book – 100-107.5µm. A. angulatus var. plana also described in Rattray, J. (1888). A Revision of the genus Aulacodiscus Ehrb. Journal of the Royal Microscopical Society, 1888: 337-382, 3 pls. page(s): p. 348 (but no pictures of it in this).