Strew slide from Ananino, Russia. Fossil marine material. Good range of species present. Mounted in Styraclor and dated July 1995. Prepared by Bernard Hartley. Olympus BHB microscope using 450nm LED light. As well as the strew, I imaged an Actinoptychus sp. using a 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).
As for species, I did initially think it might be Actinoptychus ananinensis. Original description: Pantocsek, J. (1889). Beiträge zur Kenntnis der Fossilen Bacillarien Ungarns. Teil II. Brackwasser Bacillarien. Anhang: Analyse de marine Depots von Bory, Bremia, Nagy-Kurtos in Ungarn; Ananino und Kusnetzk in Russland. Nagy-Tapolcsány, Buchdrucherei von Julius Platzko, 123 pp., 30 pls. Page 106, Plate 12, Figure 209.
Translation of the entry for it:
“Actinoptychus ananinensis n. s. tab. 12, fig. 209. — Valves rounded-hexagonal; segments 6, three primary ones elevated, appendiculated and with a distinct groove running along the central area of the dilated bare hexagon; three secondary ones depressed, separated from the 6 primary segments by robust radiating lines; structure obscurely maculose and punctate, punctae 12—14 in 10 µm. arranged in straight and oblique-decussate lines. — Diamet. Valve 116 µm.
Location: Ananino.”
At first glance this looked like a good match, however the apices for the each point on the hexagon are out of sync with mine. So I’m not sure now, and will leave it as Actinoptychus sp.