Synura tiksiensis Bessudova & Gabyshev & Likhoshway 2022, sp. nov.

Synura tiksiensis sp. nov. Bessudova, Gabyshev & Likhoshway (Figs. 6–14)

Description: Shape and dimensions of the colonies are unknown. Body scales are oval, 2.9–3.25 µm long and 1.8–2.0 µm wide. The keel is cylindrical, 0.5–0.66 µm wide, has a acute or rounded tip ornamented by medium (66-100 nm in diameter) and large pores (120-170 nm in diameter) (Figs. 7, 9). The foramen pore on the base plate is circular and large, 0.36–0.7 µm in diameter. Numerous tiny pores ornament the basal plate. The rounded struts reach the proximal rim of the scale. In some parts, they are connected by a parallel rib (Figs. 10–14). The posterior rim is narrow, 0.16– 0.19 µm wide, and encircles about half of the perimeter of the scale. Apical scales are 2.9–3.4 µm long and 1.8–2.3 µm wide (Figs. 10–14). The keel of the apical scales has a prominent, acute tip. Rear scales are 3.2–3.8 µm long and 1.2–1.5 µm wide (Figs. 6, 7). Stomatocysts are unknown.

Type: — Portion of a single gathering of scales on SEM stub No.17852 (here designated, Figure 6–14) was deposited at the Herbarium of the Limnological Institute, Siberian Branch of the Russian Academy of Sciences, Irkutsk.

Type locality:— boggy tundra, station is located on the northern slope of the Primorsky Ridge, Republic of Yakutia, Russia. Latitude / Longitude: N 71°33’35.68”, E 128°40’25.51”.

Etymology:— The species was named after the city near which it was discovered.

Distribution:— Scales were found in sites 1, 2, 3, 4, 5 and 6, at pH = 7.22–7.51, T = 14.6–16.7 °C (see Table 1).