Gomphoneis oreophila Stancheva & Kociolek, 2016

Stancheva, Rosalina, Sheath, Robert G. & Kociolek, J. Patrick, 2016, New Freshwater Gomphonemoid Diatoms from Streams in the Sierra Nevada Mountains, California, USA, Phytotaxa 289 (2), pp. 118-134 : 127

Gomphoneis oreophila Stancheva & Kociolek , sp. nov. ( Figs 46–71 )

LM observations

Valves are nearly lanceolate, slightly clavate with rounded head pole and narrower foot pole ( Figs 46–57 ). Margins are straight to convex and tumid at the center. Cells are 10.3–16 μm wide, 51–105 μm long; initial valves 15–17 μm wide, 120–125 μm long ( Figs 53, 54 ). Axial area is relatively narrow, straight and slightly expanded only at the center to form a small linear-elliptical central area bearing one stigma ( Figs 46–52 ). Raphe is slightly arched, distinctly lateral. Striae are nearly parallel to slightly radiate in the center, more strongly radiate toward the poles, 10–12 in 10 μm. Striae distinctly biseriate. Longitudinal lines located close to the valve margin (submarginal, Figs 49, 52, 54, 56 ) better visible when the valve is tilted. Initial valves bent, tumid in the center, bearing in the central area one stigma and 2 to many areolae ( Figs 53, 54 ). Frustules are cuneate in girdle view with single irregular row of puncta missing in the central part ( Fig. 58 ).

Figures

FIGURES 46–58. Gomphoneis oreophila Stancheva & Kociolek, sp. nov. type material from Rice Creek, California, USA (site 518RCNAPC). LM images. Figs 46–52, 55–57 valve view. Figs 53, 54 valve view of initial valves. Fig. 58 girdle view. Scale bar: 10 μm.

FIGURES 59–66. Gomphoneis oreophila Stancheva & Kociolek, sp. nov. type material from Rice Creek, California, USA (site 518RCNAPC). SEM images. Fig. 59 external valve view. Fig. 60 external valve view of initial cell. Fig. 61 external girdle view. Figs 62 and 63 detail of the head pole. Fig. 64 detail of foot pole with apical pore field. Fig. 65 central area with single circular stigma. Fig. 66 central area of initial cell with single stigma and several sigmoid areolae. Figs showing the same specimen are: 59, 62, 64, and 65; 60, 63, and 66. Scale bars: Figs 59–61 = 10 μm; Fig. 63 = 3 μm; Figs 62, 64, 65, 66 = 2 μm.

FIGURES 67–71. Gomphoneis oreophila Stancheva & Kociolek, sp. nov. type material from Rice Creek, California, USA (site 518RCNAPC). SEM images. Internal valve view of the same specimen. Fig. 67 shows a large axial plate and narrow marginal lamina. Fig. 68 central nodule bears a slit-like stigma and recurved proximal raphe ends. Fig 69 detail of the marginal lamina near the central area. Figs 70 and 71 detail of the marginal lamina at the foot pole. Scale bars: Fig. 67 = 10 μm; Fig. 68 = 3 μm; Fig. 70 = 2 μm; Figs 69, 71 = 0.5 μm.