Coronia samoensis (Grunow) Ruck & Guiry

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 : 52

80. Coronia samoensis (Grunow) Ruck & Guiry ( Figs 155, 156 )

Basionym: Campylodiscus samoensis Grunow.

Type locality: Samoa .

References: Podzorski & Håkansson 1987, p. 98, pl. 46, fig. 7; Stidolph et al. 2012, pl. 21, fig. 16.

Morphometrics: Valves 39 (26–39) μm long, 37 (25–37) μm wide, and central ribs 9 (12), marginal ribs 3.7 (5) in 10 μm.

Remarks: Coronia samoensis was reported from Palawan of Philippines ( Podzorski & Håkansson 1987), the West Coast of the Baja California Peninsula in Mexico ( Siqueiros-Beltrones et al. 2005), the Galapagos Islands ( Stidolph et al. 2012), Yucatán coast of Mexico, and the southern Gulf of Mexico ( López-Fuerte et al. 2017). It is a typical tropical taxon found in warmer oceans. It was reported in western and southern coast of South Korea ( Park et al. 2014), and currently rare along the Seogwipo coast in Jeju Island.

In this study, 80 taxa were selected and separated from the total diatom assemblage. They represent diatom taxa occurring mainly along the coasts of warm oceans in the tropical or subtropical regions. A variety of diatom genera, 44 kinds, have been recorded and the genera represented by the greatest number of taxa are Navicula and Campylodiscus (6 species), Amphora (5), Cocconeis (4). The most common and diverse groups of epiphytic diatoms in this area include genus Cocconeis Ehrenberg represented by C. scutellum Ehrenberg and its infraspecific taxa, and genus Achnanthes Bory , which is composed of A. angustata Greville and other a few taxa. Small-sized biraphid taxa, mainly genus Navicula , exist at the bottom as benthic forms.

Tropical diatom flora from the five sampling sites along the coast, were not evenly distributed or randomly encountered in all samples, but were concentrated at specific time periods. Based on sampling areas, tropical flora of 45 and 47 taxa were encountered in St. 1 and St. 3, respectively, and a total of 20 taxa were found in the other three sites. Compared to the number of samples collected from each site, a significantly higher number of newly reported species to South Korea were found in St. 3 than in St. 1, and 24 taxa found in St. 3 were concentrated in two epiphytic samples, collected in May 2018.

Meanwhile, a total of 48 taxa are reported for the first time in South Korea. Among the newly reported species, five species were somewhat higher in frequency or abundance: Hydrosynedra lanceolata , Cocconeis dirupta var. flexella , Navicula zostereti , Amphora staurohyalina and Cocconeiopsis orthoneiodes . The remaining taxa were rarely or very rarely found during this survey. Eighteen of the taxa were only visualized microscopically in several times: Aulacodiscus affinis , A. orientalis , Isthmia minima , Synedra bacillaris , Bleakeleya notata , Perissonoe cruciata , Ardissonea pulcherrima , Synedrosphenia gomphonema , Lyrella concilians , Fallacia vittata , Navicula plicatula , Navicula semiarea , Cymatoneis circumvallata , C. margarita , Undatella lineata , Nitzschia fluminensis , Auricula intermedia , and Coron ia impressa .

Figures

FIGURES 146–156. Diatom taxa of Seogwipo coast inJeju Island(15).Figs 146–149.Nitzschia fluminensis. Figs 150–152.Campylodiscus stellatus. Figs 153, 154. C. fastuosus. Figs 155, 156. Coronia samoensis. Scale bars = 10 μm.