Cocconeis stauroneiformis (Rabenhorst) Okuno

Joh, Gyeongje, 2021, Distribution of the genus Cocconeis (Bacillariophyceae) along the Seogwipo coast of Jeju Island, South Korea, Phytotaxa 528 (3), pp. 149-179 : 170

23. Cocconeis stauroneiformis (Rabenhorst) Okuno ( Figs 3–5 , 103, 104 )

Basionym: Rabenhorst 1864, p. 101.

References: Romero 1996, p. 371, figs 25–54; De Stefano et al. 2000, p. 237, figs 87–92; Witkowski et al. 2000, p. 116, pl. 36, figs 8, 9, pl. 54, figs 1–3; Sar et al. 2003, p. 95, figs 51–57.

Description: Valves elliptic-lanceolate to elliptical, 15–20 μm long, 8–12 μm wide. SV: sternum moderately linear to lanceolate, and central area not developed. Transapical striae broad, uniseriate, slightly radiate towards the apices, 8–11 in 10 μm, with 15–16 areolae in 10 μm of stria. RV: raphe straight, the central ends of raphe close each other, and sternum narrow. Central area transversely expanded into a hyaline fascia, up to the margins. Transapical striae slightly radiate towards the apices, 11 in 10 μm, with 16–17 areolae in 10 μm of stria. A hyaline rim in the submarginal area of valve.

Remarks: As epiphytic and benthic diatoms, Cocconeis stauroneiformis is distributed widely from the Pacific Ocean to the Antarctica (Romero 1996), and cosmopolitan from marine to brackish waters ( Witkowski et al. 2000). It occurred in Gulf of Naples of Italy ( De Stefano et al. 2000), and in Patagonian coast of Argentina ( Sar et al. 2003). In South Korea, this taxon was reported firstly as the epipsammic from the Nakdong River estuary ( Joh 2012), and in this survey, infrequent as the epiphytes on seaweeds along the Seogwipo coast.

Figures

FIGURES 3–24. LM micrographs of Cocconeis species (1). Figs 3–5. Cocconeis stauroneiformis, RV (Fig. 3) and SVs (Figs 4, 5). Figs 6–8. C. costata, SVs (Figs 6, 7) and RV (Fig. 8). Figs 9–11. C. capensis, SVs. Figs 12–19. C. distans, SVs (Figs 12, 15, 17–19) and RVs (Figs 13, 14, 16) (Figs 14 and 15, 16 and 17, complete valve). Figs 20, 21. C. pelta, SV (Fig. 20) and RV (Fig. 21). Fig. 22. C. cf. pinnata, SV. Figs 23, 24. C. clandestina, SVs. Scale bar = 10 μm (Figs 3–24).

FIGURES 100–105. SEM micrographs of Cocconeis species (10). Figs 100–102. Cocconeis convexa, the external view of SV (Fig. 100), the external view of RV (Fig. 101) and internal view of RV (Fig. 102). Figs 103, 104. C. stauroneiformis, the external views of SV. Fig. 105. Cocconeis conspicua, SV, the original drawing of Schmidt (1894b, pl.196, fig. 27). Scale bars = 1 μm (Fig. 103), 2 μm (Figs 100–102, 104), 10 μm (Fig. 105).