An arrangement of three Cosmiodiscus elegans from Santa Monica, California, USA. Prepared by William Allott Firth. 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. 60 images stacked in Zerene (Pmax).
Cosmiodiscus elegans Greville 1866. Published in: Greville, R.K. (1866). Descriptions of new and rare diatoms. Series XX [actually XIX]. Transactions of the Microscopical Society, New Series 14: 77-86, pls VIII, IX. Page 79, Plate VIII [8], Figure 13. This name is currently regarded as a synonym of Coscinodiscus perikompsos J.Rattray 1890. Source of Synonymy: Williams, D.M. (2024). Notes on the diatom collection of the Natural History Museum, London (BM) XI: the type specimens of Actinocyclus ingens Rattray and related specimens. Diatom Research 39(3): 149-158. Coscinodiscus perikompsos J.Rattray Published in: Rattray, J. (1890). A revision of the genus Coscinodiscus Ehrb., and some allied genera. Proceedings of the Royal Society of Edinburgh 16: 449-692, pls I-III. Page 576.
Cosmiodiscus elegans Grev. also in Schmidt’s Atlas Plate 229, Figures 10,11, where it says;
“10. 11. Santa Monica, f. m. Cosm. elegans Grev.
I have seen preparations made by Mr. Brun, both of which contain shells of the same frustule; on one (more convex) shell, the non-punctate radial areas are only developed near the margin, or they are completely absent; on the other, they extend to the middle and sometimes appear even more sharply defined than in the specimen illustrated in 11.
100x magnification.”