Aulacodiscus novazealandicus (various spellings of this, more in a minute) from Oamaru, New Zealand. Single example on the slide, with a process missing. Tipping downwards towards the upper edge. No makers name, but based on the the style and handwriting I think this was prepared by William Allott Firth. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 110 images stacked in Zerene (Pmax).
Aulacodiscus novae-zealandicus (Grove & Sturt) Grunow 1888. Published in: Schmidt, A.[W.F.] (1888). Atlas der Diatomaceen-kunde. Series III: Heft 31-32 [“Heft 27/28”]. pp. pls 121-128. Aschersleben: Verlag von Ludwig Siever. Plate 124, Figure 8. Basionym: Aulacodiscus sollittianus var. novae-zealandicus Grove & Sturt 1887. Published in: Grove, E. & Sturt, G. (1887). On a fossil marine diatomaceous deposit from Oamaru, Otago, New Zealand. Part II . Journal of the Quekett Microscopical Club, Series 2 3(17): 7-12, pls 2-3. Page 9, Plate 3, Figure 10 (as ‘nova-zealandica‘).