A strew from Toco, Chile. Fossil freshwater material. Mainly Campylodiscus sp. and Surirella sp.. Diatomite sample from H Jay Margolis. Diatom sample from the collection of Colonel William D Fleming, US Army, MD FRMS. Mounted in Pleurax and dated 29/5/2026. Prepared by Michel Haak. Olympus BHB microscope using 450nm LED light. As well as the wider view I imaged a couple of diatoms 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. Images stacked in Zerene (Pmax).
One has the look of an Anomoeoneis sp. Seems to be similar to Anomoeoneis costata (Kützing) Hustedt 1959. Published in: Hustedt, F. (1959). Die Kieselalgen Deutschlands, Österreichs und der Schweiz unter Berücksichtigung der übrigen Länder Europas sowie der angrenzenden Meeresgebiete. Bd. VII: Teil 2: Liefrung 6. In: Rabenhorst’s Kryptogamen Flora von Deutschland, Österreich und der Schweiz. (Anon. Eds), pp. 737-845. Leipzig: Akademische Verlagsgesellschaft m.b.h. Page 744, Figure 1111.
Reported as Anomoeoneis costata (Kützing) Hustedt: S. America: Argentina (Vouilloud, A. (2003). Catálogo de las diatomeas continentales y marinas de Argentina. pp. 1-304. Argentina: Asociación Argentina de Ficología.).
Homotypic synonyms; Navicula costata Kützing 1844, Anomoeoneis sphaerophora f. costata (Kützing) A.-M.Schmid 1977. Heterotypic synonyms; Navicula bohemica Ehrenberg 1854, Frustulia bohemica (Ehrenberg) Rabenhorst 1864, Navicula sculpta var. bohemica (Ehrenberg) Cleve & Möller 1879, Navicula bohemica var. fossilis (Ehrenberg) Grunow 1882, Anomoeoneis bohemica (Ehrenberg) Reinhard 1913.
I think the other is Surirella sella Hustedt 1925. Published in: Schmidt, A.[W.F.] (1925). Atlas der Diatomaceen-kunde. Series VIII: Heft 91. pp. pls 361-364. Leipzig: O.R. Reisland. Plate 363, Figure 7. Nice detailed species, but a challenge to image due to the shape (162 images were stacked). Dot spacing 368nm.