Halamphora montana (Krasske) Levkov, 2009

You, Qingmin, Kociolek, John Patrick & Wang, Quanxi, 2015, Taxonomic studies of the diatom genus Halamphora (Bacillariophyceae) from the mountainous regions of southwest China, including the description of two new species, Phytotaxa 205 (2), pp. 75-89 : 84-85

Halamphora montana (Krasske) Levkov ( Figs. 66–77 )

Description:— Valves semi–lanceolate, dorsiventral with smoothly convex dorsal margin and slightly convex ventral margin. Valve ends narrowly rounded to subcapitate and deflected ventrally. Length 13.3–18.0 μm, valve breadth 3.3–3.6 μm. Externally, the raphe is weakly arched and both proximal and distal raphe ends are deflected or curved towards the dorsal margin of the valve ( Figs. 71, 73, 76 ), proximal raphe ends slightly expanded ( Fig. 76 ). With narrow dorsal raphe ledge, slightly elevated from the valve face ( Figs. 71, 73, 76 ). Axial area narrow. The central area is a broad fascia on both valve sides. Beneath the raphe ledge the areolae appear to be slightly larger and lie in a shallow depression ( Fig. 76 ). Striae slightly radiate throughout, 45–50/ 10 μm, difficult to resolve with LM. Internally, the proximal raphe ends terminate at a narrow central helictoglossae ( Figs. 72, 77 ). Distally, the internal raphe ends terminate as helictoglossae ( Fig. 75 ).

Distribution and ecology:— Hezhang, Guizhou, China, altitude 1450 m a.s.l., pH 7.2, collected from a pond near the road, with many filiform green algae in the water.

Figures

FIGURES 66–77. Halamphora montana. 66–70. LM.Valve views showing size diminution series. Scale bars = 10 μm for all LM figures. 71–77. SEM. 71, 73, 74, 76. External views. 71, 74. Entire valve showing shape of the valve. 73. View of curved distal raphe end. 76. View of proximal raphe and larger areolae beneath the raphe ledge lie in a shallow depression. 72, 75, 77. Internal views. 72. Entire valve view. 75. View of valve end, with curved distal raphe ends and helictoglossa. 77. Central area with evident interrupted dorsal striae. Scale bars shown in each SEM figure.