Taxonomic studies of the diatom genus Halamphora (Bacillariophyceae) from the mountainous regions of southwest China, including the description of two new species Author You, Qingmin College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China Author Kociolek, John Patrick Author Wang, Quanxi College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China text Phytotaxa 2015 2015-04-15 205 2 75 89 http://dx.doi.org/10.11646/phytotaxa.205.2.1 journal article 10.11646/phytotaxa.205.2.1 1179-3163 13639728 Halamphora tenella Lange-Bertalot & Levkov ( Figs. 78–81 ) Description:— Valves semi-lanceolate to semi-elliptical, dorsiventral with smoothly convex dorsal margin and slightly concave ventral margin. Valve ends narrowly rounded, weakly ventrally bent. Length 14.3–16.0 μm, valve breadth 3.0–4.0 μm. Striae with fine areolae, slightly radiated throughout, dorsal striae 24–26/10 μm, striae in other part hard to resolve with LM. Distribution and ecology:— Namtso Lake, Tibet , China , altitude 4729 m a.s.l., pH 9.7, water temperature 16 ºC, collected in the pond near the Namtso Lake, with many Chara Vaill. in the water. Observations:— This species has a valve outline similar to H . veneta ( Kützing 1844: 108 ) Levkov (2009: 242) , however, H . veneta is larger (length 17–35 μm, valve breadth 4.0–6.5 μm,) and has less dense striae (dorsal striae 18–22/10 μm).