Shionodiscus endoseriatus (Hasle & Fryxell) Alverson, Kang & TheriotThalassiosira endoseriata Fryxell and Hasle (1977): 78, pl. 8, figs. 45–49 — Fryxell and Hasle (1980); Rivera Ramírez (1981): 68, figs. 145–157; Mahood et al. (1986): 146, fig. 91; Hasle and Syvertsen (1997): 81, 82, pl. 13; Guiry and Guiry (2025).Shionodiscus endoseriatus — Alverson et al. (2006); Wilks and Armand (2017).DescriptionDiameter 30.0–54.1 (20–60) µm. Valve face flat or slightly convex. Irregular ring of 8–10 (4–14) central fultoportulae. Rimoportula is 7 (6) areolae from the margin towards centre of valve. Areolae usually fasciculate, 8–12 (11–18) in 10 μm at valve centre. MFP 6–8 (5–6) in 10 µm and extending into interior of frustule.NotesSpecimens from the Strait of Georgia conform well with the published data. iNaturalist ID: 259613928 (Fig. 32).