Cocconeis pellucida Grunow, 1863

Joh, Gyeongje, 2021, Distribution of the genus Cocconeis (Bacillariophyceae) along the Seogwipo coast of Jeju Island, South Korea, Phytotaxa 528 (3), pp. 149-179 : 161

15. Cocconeis pellucida Grunow ( Figs 84–86 )

Basionym: Rabenhorst 1863, p. 21, pl. 6, fig. 11.

References: Hustedt 1933, p. 357, fig. 812; Kobayasi & Nagumo 1985, p. 102, pl. 3, figs 28–40; Witkowski et al. 2000, p. 111, pl. 34, figs 1–3.

Description: Valves broadly elliptical to almost orbicular, 47–104 μm long, 40–95 μm wide. SV: sternum broadly linear and widened in the middle. Central area not developed. Transapical striae radiate towards the apices, 30–34 in 10 μm, but regularly interrupted by several longitudinal hyaline lines appearing to form many longitudinal folds, areolae in a stria transapically elongated. RV: both raphe and sternum slightly sigmoid, sternum narrow, the terminal ends of sternum expanded to crescent hyaline area and distant from the apices. Central area small and rhombic. Valves between the raphe and the margins slightly depressed. Transapical striae radiate, 18–24 in 10 μm.

Remarks: This species is common in warmer oceans and in the Mediterranean, and has rarely been reported from Europe ( Hustedt 1933, Witkowski et al. 2000). It occurred in the coasts of Japan ( Takano 1962, Kobayasi & Nagumo 1985), South Africa ( Giffen 1970), Brazil ( Procopiak et al. 2006), the New Hebrides (now Vanuatu) ( Stidolph et al. 2012), and Mexico ( López-Fuerte & Siqueiros-Beltrones 2016). In South Korea, this taxon was reported as pelagic planktons from Korea Strait ( Skvortzow 1932), as plankton and periphytes off the coast of Jeju Island ( Lee et al. 1990, 1991), and in this survey, occurred rarely as epiphytes on seaweeds collected from St. 2 in the Seogwipo coast.

Figures

FIGURES 84–87. LM micrographs of Cocconeis species (7). Figs 84–86. Cocconeis pellucida, SVs (Figs 84, 85) and RVs (Figs 85, 86), internal view (Fig. 84) and external view of SV (Fig. 86). Fig. 87. C. conspicua, SV. Scale bars = 10 μm (Figs 84–87).