An arrangement of three Cestodiscus superbus from Barbados. Prepared by Clarke and Page. Olympus BHB microscope using 450nm LED light. 20x Nikon Plan Apo NA 0.65 objective. Olympus Aplanat Achromat condenser, brightfield lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 20 images stacked using Zerene (Pmax).
As you will no doubt have noticed this is quite a low resolution image. I had hoped to image it with either my 40x or 63x Leitz Pl Apo objective, but either the coverslip is too thick, or the diatoms were mounted too deeply to allow me to do this. Hence I needed to use the 20x Nikon Plan Apo NA 0.65. They could look nicer with a higher NA, higher magnification objective, if I had one with sufficient working distance.
Right, the name. These do very much look like Cestodiscus to me, and I have seen the name Cestodiscus superbus on other slides. I think it was originally called Coscinodiscus superbus var. novazealandica, which is another name for Cestodiscus pulchella var. novazelandica and which is present in Barbados. However, there’s more. Visually there are more similarities to Cestodiscus fennerae and also Cestodiscus trochus to me than for (for example see “Strelnikova, N.I., Fourtanier, E., Kociolek, J.P. and Barron, J.A. 2001. Ultrastructure studies of Coscinodiscus and Cestodiscus species from the Eocene and Oligocene. In: Jahn, R., Kociolek, J.P., Witkowski, A. & Compère, P. (eds), Lange-Bertalot-Festschrift: Studies on Diatoms. pp. 63-96.). However I will leave it as labelled for now.