Two examples of Coscinodiscus lobatus from Barbados. Mounted in Sirax and dated April 1941. Prepared by Samuel Henry Meakin. Olympus BHB microscope using 450nm LED light. As well as the pair I imaged the right hand 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. 23 images stacked in Zerene (Pmax).
Coscinodiscus lobatus Barker & Meakin, 1946. Original description: Barker, J.W. & Meakin, S.H. (1946). New and rare diatoms. Journal of the Quekett Microscopical Club, Series 4, 2(2): 76-79, pls 15, 16. Page 76, Plate 15, Figure 4.
Interestingly this slide predates Meakin’s publication by 5 years. Originally on the slide it was described as ‘Coscinodiscus n. sp.’. Then ‘lobatus’ has been written presumably at a later date to making the slide.
I am working on the assumption that this is the same as Coscinodiscus radiatus var. irregularis as shown here.