Halamphora navalis sp. nov. (Amphipleuraceae, Bacillariophyta), a new hull-fouling diatom from the research vessel Jangmok No. 1, Korea

The diatom genus Halamphora exhibits a broad ecological distribution, which has led to the differentiation of numerous species within the group. Here, we isolated a marine Halamphora sp. strain (BD002) from the hull surface of the Korean research vessel Jangmok No. 1 anchored at Jangmok Bay, South Korea. We examined the morphology of the diatom species using light and scanning electron microscopes and found that it differed from already-known Halamphora species. It is very small in size (5.0–9.1 µm in length), and the combination of weakly protracted valve apices, absence of longitudinal rib, detail of raphe ledge, and stria structure is distinctive among other small Halamphora species, including H. minima and H. witkowskii. Phylogenetic analyses of the nuclear 18S, 28S rDNA, and chloroplast rbcL showed that the BD002 strain was placed in a unique genetic position within the Halamphora clade. These results strongly suggest that strain BD002 is a novel species within the genus Halamphora, and thus, we propose the name, Halamphora navalis sp. nov., after the first reported habitat.