This post contains images from 4 strew slides prepared by Laurence Miles. Three of these are from sites in the USA and the other is from Japan. Olympus BHB microscope using 450nm LED light. For the wide field images of the strews I used a 10x Nikon Plan Apo NA 0.45 objective. Olympus Aplanat Achromat condenser, brightfield lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera.
First, from Richmond, Virginia, USA.
Second, from Rappahannock cliffs (spelt Rappahanock on the slide), Virginia, USA.
Third from Patuxent river, Maryland, USA.
As well as the strew, I took a high resolution stack 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. 100 images stacked in Zerene.
Lower left of the stacked image – chrysophyte cyst (for some nice example SEM images of these types of cysts – although probably a different species – see Siver, P.A. Remarkably preserved cysts of the extinct synurophyte, Mallomonas ampla, uncovered from a 48 Ma freshwater Eocene lake. Sci Rep 10, 5204 (2020). https://doi.org/10.1038/s41598-020-61993-1). Also see Tynan, Eugene J. “The Archaeomonadaceae of the Calvert Formation (Miocene) of Maryland.” Micropaleontology, vol. 6, no. 1, 1960, pp. 33–39. JSTOR, https://doi.org/10.2307/1484315 for examples of cysts from the Calvert formation in Maryland. Maybe Archaeosphaeridium ornatum Deflandre, 1932. Original description: Deflandre, G. (1932). Note sur les Archæomonadacées. Bulletin de la Société Botanique de France, 79(3): 346-355, 38 figures.
Upper right of the stacked image – Eupyxidicula sp.. Perhaps E. turris as this has reported in Maryland diatomite and visually it looks like a pretty good match. Eupyxidicula turris (Greville) S.Blanco & C.E.Wetzel 2016. Published in: Blanco, S. & Wetzel, C.E. (2016). Replacement names for botanical taxa involving algal genera. Phytotaxa 266(3): 195-205. Page 197. Formerly known as Stephanopyxis turris 1861. Published in: Pritchard, A. (1861). A history of infusoria, including the Desmidiaceae and Diatomaceae, British and foreign. Fourth edition enlarged and revised by J. T. Arlidge, M.B., B.A. Lond.; W. Archer, Esq.; J. Ralfs, M.R.C.S.L.; W. C. Williamson, Esq., F.R.S., and the author. pp. [1]-xii, [1]-968, 40 pls [I-XV]. London: Whittaker and Co.. Page 826, Plate 5, Figure 74.
Thanks to Jakub Witkowski for information which helped with naming these.
Finally a strew from Sandai [Sendai], Japan.
As well as the strew, I took a high resolution stack of what looks be Odontella weissflogii 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. 91 images stacked in Zerene. This is tipping down away from the coverslip towards the upper left.
Odontella weissflogii (Grunow) Grunow 1884: 6. Published in: Grunow, A. (1884). Die Diatomeen von Franz Josefs-Land. Denkschriften der Kaiserlichen Akademie der Wissenschaften. Mathematisch-Naturwissenschaftliche Classe, Wien 48 (Abt. 2): 53-112, 5 pls. Page 58, no image. My ID of Odontella weissflogii came from Mary Ann Tiffany’s document on Dunkirk diatoms from here. Interestingly, Mary noted that these do not look like typical Odontella, and could potentially be resting spores.