Gomphonema sierrianum 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 : 125-126

Gomphonema sierrianum Stancheva & Kociolek , sp. nov. ( Figs 28–45 )

LM observations

Valves are lanceolate-clavate with produced broadly rostrate to slightly capitate head pole and narrower rounded foot pole ( Figs 28–39 ). Cells are 4–5.2 μm wide, 17–31 μm long. The axial area is wide, lanceolate bordered by short striae. Striae at the center are slightly radiate and shortened, becoming strongly radiate toward the poles, 11–14 in 10 μm. Areolae not distinguishable in LM.

The raphe is filiform, with weakly expanded proximal ends that are bent slightly to one side. A single, small stigma is present at the central area. Frustules are cuneate in girdle view with single irregular row of puncta on each mantle interrupted in the central part ( Fig. 34 ).

view. Figs 41, 42, 45 external valve view. Fig. 43 girdle view showing each mantle with pores near both poles. Fig. 44 illustrates the interval view of the central nodule, bearing a circular, slightly transversely elongated stigma opening and dilated and recurved proximal raphe ends. Fig 45 shows external valve view of the central area with isolated stigma. Figs 42 and 45 are the same specimen. Scale bars: Figs 40–43 = 2 μm; Figs 44, 45 = 1 μm.

Figures

FIGURES 28–39. Gomphonema sierrianum Stancheva & Kociolek, sp. nov. type material from San Antonio Creek, California, USA (site 533SPILSA). LM images. Figs 28–33, 35–39 valve view. Fig. 34 girdle view. Scale bar: 10 μm.

FIGURES 40–45. Gomphonema sierrianum Stancheva & Kociolek, sp. nov. type material from San Antonio Creek, California, USA (site 533SPILSA). SEM images. Figs 40, 44 internal valve