Halamphora daochengensis sp. nov., a new freshwater diatom species (Bacillariophyceae) from a small mountain lake, Sichuan Province, China Author Zhang, Wei Centre for Research on Environmental Ecology and Fish Nutrition (Ministry of Agriculture, China), Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Ministry of Education, China), National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, P. R. China Author Wang, Ting Centre for Research on Environmental Ecology and Fish Nutrition (Ministry of Agriculture, China), Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Ministry of Education, China), National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, P. R. China Author Levkov, Zlatko Faculty of Natural Sciences, Institute of Biology, Arhimedova 3, 1000 Skopje, Republic of North Macedonia Author Jüttner, Ingrid Department of Natural Sciences, National Museum of Wales, Cathays Park, Cardiff CF 103 NP, UK Author Ector, Luc Luxembourg Institute of Science and Technology (LIST), Environmental Research and Innovation Department (ERIN), 41 rue du Brill, 4422 Belvaux, Luxembourg Author Zhou, Qi-Chao Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake-Watershed, Yunnan Institute of Environmental Science, Kunming 650034, P. R. China & Key Laboratory of Plateau Lake Ecology and Environment Change, Institute of Plateau Lake Ecology and Pollution Management, School of Resource Environment and Earth Science, Yunnan University, Kunming 650500, P. R. China & Centre for Research on Environmental Ecology and Fish Nutrition (Ministry of Agriculture, China), Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Ministry of Education, China), National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, P. R. China text Phytotaxa 2019 2019-05-16 404 1 12 22 http://dx.doi.org/10.11646/phytotaxa.404.1.2 journal article 10.11646/phytotaxa.404.1.2 1179-3163 13715773 Halamphora daochengensis W. Zhang, Jüttner & Levkov sp . nov . ( Figs 1–25 ) LM: Valves dorsiventral, moderately arched, with triundulate, convex dorsal margin, straight to slightly concave ventral margin ( Figs 1–9 ). Valve ends protracted, capitate. Dimensions: length 34.3–40.8 μm, width 5.4–6.9 μm. Axial area very narrow, central area indistinct. Raphe arched, proximal ends weakly expanded, slightly dorsally deflected, distal ends dorsally deflected. Dorsal striae with fine punctuation, slightly radiate throughout, 23–25(27) in 10 μm dorsally at valve centre, 24–27 in 10 μm ventrally, 28–30 in 10 μm near valve ends. SEM: Externally, raphe located in flat, narrow ledge, slightly wider in valve centre ( Figs 10, 11 , 14, 17 ). Ledge ornamented with shallow, non-penetrating depressions, rounded or irregular in shape with variable size ( Figs 14, 17 ). Striae uniseriate, composed of elongate areolae of variable length ( Fig. 10–19 ). Dorsally, striae continuing uninterrupted onto mantle, mantle with 3–4 rows of areolae of variable length in valve centre, and one row of elongate areolae near valve ends ( Figs 12, 13 ). Ventrally, striae composed of one row of transapically elongated areolae ( Figs 11 , 14–16 ). Girdle bands open, each bearing one or two rows of rounded or slightly transapically elongated poroids similar in size to ventral areolae ( Figs 14–16 , 20, 24 ). Internally, distal raphe ends slightly ventrally deflected terminating in large helictoglossae ( Figs 22, 23 ). Proximally, raphe ends terminating in wide fused central helictoglossa ( Fig. 25 ). Type: — CHINA . Sichuan Province : Tibetan Autonomous Prefecture of Garzi , Daocheng County , Haizishan Nature Reserve , Lake Congqiancuo , 29°21′58″ N , 100°04′51″E , elevation 4389 m a.s.l. , samples collected by Q.C. ZHOU , 20 Sep. 2018 . Holotype NMW .C.2019.01! Amgueddfa Cymru — National Museum Wales , isotype slide CQC1#, SHOU ! Department of Hydrobiology , College of Fisheries and Life Science , Shanghai Ocean University ( SHOU ), Shanghai . Etymology: —The specific epithet ‘ daochengensis ’ refers to the locality from which the new species was described.