Aulacodiscus affinis Grunow, 1876

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 : 7

1. Aulacodiscus affinis Grunow ( Figs 10, 11 )

Type locality: Gaz. Exped.; Japan.

References: Schmidt et al. 1874–1959, pl. 34, figs 9, 10; Siqueiros-Beltrones & Argumedo-Hernández 2014, figs 26–28.

Morphometrics: Valves 113–178 μm in diameter, striae radiate from the center, 5–8 in 10 μm, areolae 3–5 in 10 μm on a stria. Eight pseudocelli on elevations in the corner of valve.

Remarks: Aulacodiscus affinis is very rare worldwide and its existence is not well known. This taxon was only reported from a few localions worldwide, including the Pliocene sediments of Shikotan Island and Lesser Kuril Ridge in Russia ( Terekhov et al. 2011), and from Magdalena Bay along the western coast of the Baja California Peninsula in Mexico as epiphytes on red seaweed ( Siqueiros-Beltrones and Argumedo-Hernández 2014). It was also very rare in diatom assemblages obtained from the Seogwipo coast, Jeju Island, representing a new record for South Korea.

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.