An arrangement of three Navicula mexicana (and a sponge spicule) from Tampa Bay, Florida, USA. Two of them look strangely asymmetric to me, but that could be how they are mounted (slightly tilted). Prepared by JA Long. Olympus BHB microscope using 450nm LED light. The middle one was imaged at a higher resolution using a 63x Leitz Pl Apo NA 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oblique lighting, oil immersion. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 49 images stacked in Zerene (Pmax).
Navicula mexicana (Heiden) Mann 1925. Published in: Mann, A. (1925). Marine diatoms of the Philippine Islands. Bulletin United States National Museum 100(6, part 1): 1-182, 39 pls. Page 110. This name is currently regarded as a synonym of Caloneis mexicana Heiden 1906. Published in: Schmidt, A.[W.F.] (1906). Atlas der Diatomaceen-kunde Series VI: Heft [66]. pp. pls 261-264. Bearbeitet von Dr. M. Schmidt. Leipzig: O.R. Reisland. Plate 264, Figures 3,7.