An arrangement of Auliscus radiatus (fossil marine) from Maryland, USA. Prepared by Eduard Thum, but with labels from C Baker, London, who was Thum’s UK distributor in the early 1900s (see his entry on Microscopist.net here). One of them has gone on a big walkabout, as can be seen in the 4x objective image. The remaining ones look fine, and a couple of them are in very good condition, better than my other slides of this species. I image two at higher magnification. 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. 32 images stacked in Zerene (Pmax).
This is also known as Pseudauliscus radiatus. P. radiatus is currently regarded as a synonym of Mastodiscus radiatus (Bailey) A.K.S.Prasad & Nienow. Published in: Sims, P.A., Williams, D.M. and Ashworth, M. (2018) Examination of type specimens for the genera Odontella and Zygoceros (Bacillariophyceae) with evidence for the new family Odontellaceae and a description of three new genera. Phytotaxa 382: 1-56.