I think this Azpeitia biradiata, from a strew slide of Oamaru “Per Craigie”, New Zealand, prepared by Mike Samworth. It is missing its rim. Mounted in Naphrax. Slide says ex LNB, No. 613, 01/01. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo NA 1.40 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, brightfield. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 29 images stacked in Zerene (Pmax).