Eunotia yunnanica Q. Liu, S.L.Xie & Kociolek

Liu, Qi, Liu, Enhui, You, Qingmin, Wang, Qinghua, Kociolek, John Patrick & Xie, Shulian, 2024, New and Interesting Diatoms from the Shiwan Wetwalls, Yunnan Province, China. III. Valve ultrastructure of four new species of Eunotia (Bacillariophyceae: Eunotiales), Phytotaxa 642 (4), pp. 242-254 : 243-244

Eunotia yunnanica Q. Liu, S.L.Xie & Kociolek sp. nov. (LM: Figs 1–11, SEM: Figs 12–17)

Description: LM: Valves asymmetrical to apical axis, dorsal margin convex outline appearing undulate, with produced, rounded ends; smaller valves with less produced apices. Ventral margin slightly concave to nearly straight; some specimens with slight degree of asymmetry about transapical axis. Valve length 21–52 µm; 6–8 µm; 5–6/10 µm. Striae not punctate (in LM), wider at dorsal margin, becoming narrow across valve face, parallel and widely spaced in valve center. Striae crossing valve face 5–6/10µm, denser at apices, 7–9/10 µm. Distal raphe ends barely extend onto valve face before valve terminus. Pseudoseptum present at each apex. In girdle view, dorsal portion of valve with multiseriate, punctate striae separated by hyaline areas. Striae appear in bundles of 3–5, distinctly punctate. Margin with spine-like projections. On ventral portion of valve mantle, raphe branches short, contained in narrow axial area. Raphe branches bent towards mantle, away from valve face.

SEM: valve exterior with thickened ribs or ridges extending across valve face, dorsal margin also appears thickened, giving margin an undulate appearance (Figs 13, 14). Striae composed of 2–4 rows of round, unoccluded areolae at dorsal margin, except at apices (Figs 13–15). Striae uniseriate across valve face to ventral margin. Distal raphe end extending onto valve face (Fig. 15). Internally, areolae round, appear without occlusions (Figs 15, 16). Small pseudoseptum at apices. Raphe terminates in prominent helictoglossa (Figs 15, 17).

Type: CHINA. Yunnan Province, Shiwan wet wall. Holotype preparation Slide No. YN201904033- 1 in the Freshwater Algal Herbarium of Shanxi University ( SXU), Taiyuan, China. Isotype slide YN201904033-2 deposited in the Kociolek Collection at the University of Colorado ( COLO) .

Etymology: Named for its occurrence in Yunnan Province, China.

Comments: This taxon was reported by Luo et al. (2019), as Eunotia odebrechtiana Metzeltin & Lange-Bertalot (1998) , from streams and lakes in Sichuan Province. They noted that the Chinese specimens were narrower than the specimens described by Metzeltin and Lange-Bertalot (1998) from Brazil. Specimens from Yunnan are also narrower than the South American species and, like the specimens from Sichuan illustrated by Luo et al. (2019), they have finer striae.

Present in samples YN201904033, YN201904034, YN201904047, YN201904049 and YN201904055.