Gyrosigma procerum Hustedt 1956

Lee, Sang Deuk, Yun, Suk Min, Cho, Pyo Yun, Yang, Hye-Won & Kim, Oe Jung, 2019, Newly Recorded Species of Diatoms in the Source of Han and Nakdong Rivers, South Korea, Phytotaxa 403 (3), pp. 143-170 : 161

Gyrosigma procerum Hustedt 1956 *

Figures 70–74

Original description: Hustedt (1956), p. 118, fig. 48.

Key literatures: Watanabe et al. (2005), p. 237, pl. IIB3-4, fig. 1–3; Wang et al. (2010).

Specimen examined: Tables 1, 2.

Dimension. Length 103.1 μm, width 13.3 μm; 23–25 striae in 10 μm on the raphe valve.

Description: Valves are slender and sigmoid with smoothly tapering to acutely cuneate ends. The central area is longitudinally and small elliptical. The raphe is straight and central for half its length, and follows a sigmoid shape and is slightly eccentric toward each convex side.

Proximal raphe fissures strongly sinuous towards the opposite direction, proximal end expended, distal ends hooked in the opposite directions. Striae areolate, transverse and longitudinal.

Remarks: The cell length 70–130 μm, width 13–18 μm, striae 19–21 in 10 μm described by ( Wang et al. 2010).

Distribution and ecology: Gyrosigma procerum appeared in the sediment core samples of Liyu Lake, a lowland natural lake situated at Hualen, eastern Taiwan ( Wang et al. 2010).