Fragilaria recapitellata Lange-Bertalot & Metzeltin

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 : 160

Fragilaria recapitellata Lange-Bertalot & Metzeltin in Metzeltin, Lange-Bertalot & Nergui 2009* Figures 58–62

Synonyms: Synedra capitellata Grunow 1881 ; Synedra vaucheriae var. capitellata (Grunow) Hustedt 1930 ; Fragilaria intermedia var. capitellata (Grunow) A. Cleve 1932; Fragilaria capitellata (Grunow) J.B. Petersen 1946 ; Fragilaria vaucheriae var. capitellata (Grunow) R. Ross 1947 .

Original description: Metzeltin et al. (2009), p. 48.

Key literatures: Cantonati et al. (2017); Delgado et al. (2015); Tuji & Williams (2008).

Specimen examined: Tables 1, 2.

Dimension: Length 25.7–37.5 μm, width 4.2–5.1 μm; 15–17 striae in 10 μm on the valve.

Description: Valves are lanceolate, linear, and narrow with strongly rostrate to subcapitate ends. The central margin is unilaterally expanded. Valve face slightly flat, rimoportulae find near the poles, and the apical pore fields are grids. The colonies are attached by a mucilage pad on the frustule. The central area is unilateral, often expanded until the sternum. The striae are mostly parallel, to slightly radiate toward the valve ends, and alternate. Striae extend onto the valve mantle.

Remarks: The combination of the unilateral central area and capitate ends distinguishes this species from other representatives of the F. capucina complex with similar stria density ( Delgado et al. 2015). F. capucina has valves of similar width but with a lower stria density (12–17 in 10 μm) ( Cantonati et al. 2017). The cell length 20–39 μm, width 3–4 μm, striae 17–19 in 10 μm, 60–65 puncta in 10 μm described in type material ( Tuji & Williams 2008).

Distribution and ecology: This species distributed in Oligotrophic to mesotrophic, electrolyte-poor streams and small rivers on siliceous substrate ( Cantonati et al. 2017). The species widely distributed, locally in very high numbers in central Europe ( Cantonati et al. 2017).