Record of two rare taxa from Synura genus (Chrysophyceae) with a description of a new species (Synura tiksiensis sp. nov.) near the arctic settlement of Tiksi, Yakutia, Russia Author Bessudova, Anna 0000-0002-6569-0052 Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 3 Ulan-Batorskaya, 664033 Irkutsk, Russia & annabessudova @ mail. ru; https: // orcid. org / 0000 - 0002 - 6569 - 0052 annabessudova@mail.ru Author Gabyshev, Viktor 0000-0002-1656-4383 Institute for Biological Problems of Cryolithozone, Siberian Branch of the Russian Academy of Science, 41 Lenin Avenue, 677980 Yakutsk, Russia & v. a. gabyshev @ yandex. ru; https: // orcid. org / 0000 - 0002 - 1656 - 4383 v.a.gabyshev@yandex.ru Author Likhoshway, Yelena V. 0000-0002-2432-9260 Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 3 Ulan-Batorskaya, 664033 Irkutsk, Russia & likhoshway @ mail. ru; https: // orcid. org / 0000 - 0002 - 2432 - 9260 likhoshway@mail.ru text Phytotaxa 2022 2022-09-01 560 2 247 253 http://dx.doi.org/10.11646/phytotaxa.560.2.8 journal article 10.11646/phytotaxa.560.2.8 535943f7-5d9a-43bc-a225-951e812d5c43 1179-3163 7040711 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 ).