Pseudictyota dubium (Brightwell) Sims & Williams

Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, Phytotaxa 517 (1), pp. 1-67 : 16

18. Pseudictyota dubium (Brightwell) Sims & Williams ( Figs 2–4 , 182, 183 )

Synonym: Triceratium dubium Brightwell ; Biddulphia dubia (Brightwell) Cleve ; Odontella dubia (Brightwell) Chavez & Baumgartner.

Type locality: Mauritius .

References: Hustedt 1927 –1930, p. 806, fig. 469; Podzorski & Håkansson 1987, p. 29, pl. 5, figs 5, 7; Witkowski et al. 2000, p. 42, pl. 8, figs 4, 5; Fernandes & de Souza-Mosimann 2001, p.161, figs 22–36; Sims et al. 2018, pl. 37, figs 133–138.

Morphometrics: Valves 30–34 μm long apically, 25–29 (20–100) μm in side length, 31–32 μm wide transapically, areolae on a stria 4–5 (4–5) in 10 μm.

Remarks: Pseudictyota dubium is distributed in the littoral waters of warmer oceans and in the southern region of Europe ( Hustedt 1927 –1930). This taxon has been reported from many places: Heron Island and port Hacking in Australia ( Crosby & Wood 1958), Palawan of Philippines ( Podzorski & Håkansson 1987), the Tavares River mangrove of Brazil ( Felício-Fernandes et al. 1994), Paranaguá Bay of southern Brazil ( Fernandes & Souza-Mosimann 2001), Yap and Guam in the western Pacific Ocean ( Navarro & Lobban 2009, Theriot et al. 2010), Galapagos Islands ( Stidolph et al. 2012), and Red Sea ( Gerasimiuk & Kovtun 2014). In addition, it is mentioned on the phytoplankton check-list near Vero Beach of Florida ( Mahoney & Gibson 1983), and that of the Caribbean Sea ( Navarro & Hernández-Becerril 1997), and is widespread on warmer coasts. It was collected from the islands in the northern Yellow Sea of South Korea ( Lee et al. 2015), and currently encountered infrequently as an epiphyte along the Seogwipo coast in Jeju Island.

Figures

FIGURES 2–11. Diatom taxa of Seogwipo coast in Jeju Island (1). Figs 2–4. Pseudictyota dubium. Fig. 5, 6. Trigonium formosum. Fig. 7. Triceratium reticulum. Fig. 8. Asteromphalus flabellatus. Fig. 9. Aulacodiscus orientalis. Fig. 10, 11. A. affinis. Scale bars = 10 μm.

FIGURES 176–184. Diatom taxa of Seogwipo coast in Jeju Island (18). Fig. 176. Auricula complexa. Fig. 177. A. flabelliformis. Figs 178, 179. A. intermedia. Figs 180, 181. Pseudictyota reticulata: external view of valves, and large ocellus and a rimoportula tube (Fig. 180). Figs 182, 183. P. dubium: internal (Fig. 182) and external view (Fig. 183) of valve. Figs 176–179: LM, Figs 180–184: SEM. Scale bars = 10 μm (Figs 176–179, 181, 183, 184), 5 μm (Fig. 182), 2 μm (180).