An arrangement of three diatoms labelled as Coscinodiscus jonesianus from Southampton waters, UK. Mounted in Hyrax and dated 17/9/1994. Prepared by Klaus Kemp. Olympus BHB microscope using 450nm LED light. As well as the arrangement I imaged the lower left one using the 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. 53 images stacked in Zerene (Pmax). Slightly less sharpening than usual for the 63x (4.5 unsharp mask). Approx 98µm diameter measured in ImageJ.
Coscinodiscus jonesianus (Greville) Ostenfeld, 1915. Published in: Ostenfeld, C.H. (1915). A List of Phytoplankton from the Boeton Strait, Celebes. Dansk Botanisk Arkiv 2(4): 1–18, 10 figures. Page 13, Figure 7. This name is currently regarded as a synonym of Coscinodiscopsis jonesiana (Greville) E.A.Sar & I.Sunesen, 2008. Published in: Sar, E.A., Sunesen, I. & Hinz, F. (2008). Fine morphology of Coscinodiscus jonesianus and Coscinodiscus commutatus and their transfer to Coscinodiscopsis gen. nov. Diatom Research 23(2): 401-421. Page 419.
I am however leaving a question mark with this one, as it does not show the obvious large macrorimoporulae characteristic of this species, which puts doubts in my mind.