Skip to main content

Hampyeong Bay diatom (Halamphora hampyeongensis) from a tidal mudflat in South Korea

Hampyeong Bay diatom (Halamphora hampyeongensis) from a tidal mudflat in South Korea

NEWS - Researchers describe a benthic diatom found in the intertidal mudflats of South Korea, based on morphological and molecular characteristics, similarities and differences between Hampyeong Bay diatom (Halamphora hampyeongensis sp. nov.) and other morphologically similar Halamphora species.

Several molecular phylogenetic studies provide strong evidence supporting the monophyletic status of Halamphora as a distinct group separate from Amphora sensu stricto. Since its recognition as a genus, there has been an increase in understanding of the diversity within Halamphora. Furthermore, there has been a significant increase in the determination of new species. The genus includes 155 valid species, including 8 varieties.

Sung Min An from the National Marine Biodiversity Institute of Korea in Seocheon and his team used light and electron microscopy to conduct morphological examinations of the new species isolated from the intertidal mudflats of Hampyeong Bay, South Korea. Molecular analysis used 18S rDNA and rbcL genes.

H. hampyeongensis has a semi-elliptical valve LM with a smoothly convex dorsal margin, a nearly straight ventral margin, and a narrowly rounded valve tip that curves slightly ventrally. The raphe is slightly curved and positioned midway to slightly ventrally on the valve surface. Dorsal and ventral striae are not visible. The valve length is 13.8-15.0 μm, and the valve width is 2.8-3.0 μm.

The specific epithet “hampyeongensis” refers to the type locality, Hampyeong Bay, Muan-gun, Jeollanam-do, South Korea. This species is a benthic species currently only known from the type locality. The sediment temperature and pore water salinity in the sediment at the time of sampling were 27.8°C and 24.9 psu, respectively.

The lengths of the 18S rDNA and rbcL gene sequences were 1,649 bp and 1,424 bp, respectively. Phylogenetic analysis provides strong support for a monophyletic grouping of Halamphora species including H. hampyeongensis, as indicated by a maximum likelihood bootstrap support of 98% and a Bayesian posterior probability of 0.99.

H. hampyeongensis is located in the Halamphora Clade Hal_H with low bootstrap value (bootstrap value = 25) and weak support (bootstrap value = 63) as the sister taxon to H. montana (Krasske) Levkov. This species is related to H. exilis, H. mosensis, H. specensa, H. maritima (J.G.Stepanek & Kociolek) and H. nipponensis (J.G.Stepanek, S.Mayama & Kociolek).

This clade is characterized by the absence of a dorsal marginal ridge, the presence of a biseriate internal areola occlusion and an internal areola occlusion of the hymen. In particular, H. maritima and H. nipponensis show clear differences from other species in the clade, particularly in their narrow ventral valves and ventral striae, which are composed of elongated areoles. In contrast, other species typically have relatively wide ventral valves and fine uniseriate ventral striae as in the new species.

H. hampyeongensis shares similarities with H. caribaea (Wachnicka & E.E.Gaiser) Rimet & R.Jahn, H. exilis, H. mosensis, and H. specensa in the overall valve outline, the relatively wide ventral side of the valve, and specific striae characteristics, including fine uniseriate ventral striae and biseriate dorsal striae near the axial area.

H. hampyeongensis has smaller areolae and denser striae with 34-38 in 10 μm, compared to 11-20 in 10 μm in H. caribaea and 24-26 in 10 μm in H. exilis. Unlike H. hampyeongensis, H. mosensis has multi-seriate dorsal striae and H. specensa has convex ventral margins and irregular bi-seriate dorsal striae.

H. hampyeongensis has smooth areolae like H. atacamana (Patrick) Levkov and H. montana. However, H. atacamana can be distinguished from H. hampyeongensis by its lower valve lines and striae density (25-28 in 10 μm) and H. montana has semi-stauros.

Although benthic diatoms are dominant organisms in benthic ecosystems in tidal areas and are known for their high diversity, a comprehensive understanding of them is still limited. In the future, further research is needed to explain the species richness of diatoms in tidal areas.

Original research

An SM, Kim J, Cho K, Hwang H-J (2024). Halamphora hampyeongensis sp. nov. (Amphipleuraceae, Bacillariophyceae), a new marine benthic diatom from a tidal mudflat in Hampyeong Bay, South Korea. PhytoKeys 248: 59-71, DOI:10.3897/phytokeys.248.135034

Dlium theDlium
Labels:

Popular Posts

Humpback whales (Megaptera novaeangliae) manufacture bubble-nets as tools to increase prey intake

NEWS - Humpback whales ( Megaptera novaeangliae ) create bubble net tools while foraging, consisting of internal tangential rings, and actively control the number of rings, their size, depth and horizontal spacing between the surrounding bubbles. These structural elements of the net increase prey intake sevenfold. Researchers have known that humpback whales create “bubble nets” for hunting, but the new report shows that the animals also manipulate them in a variety of ways to maximize catches. The behavior places humpbacks among the rare animals that make and use their own tools. “Many animals use tools to help them find food, but very few actually make or modify these tools themselves,” said Lars Bejder, director of the Marine Mammal Research Program (MMRP), University of Hawaii at Manoa. “Humpback whales in southeast Alaska create elaborate bubble nets to catch krill. They skillfully blow bubbles in patterns that form a web with internal rings. They actively control details such ...
Read more

Red costate tiger moth (Aloa lactinea)

Red costate tiger moth ( Aloa lactinea ) is an animal species in the Erebidae, a moth with a wingspan of 40 mm, a yellow belly, black antennae with red basalt joints, dark red palpi on the sides and white below, black terminal joints, living in forests and agriculture in the lowlands to mountainous areas. A. lactinea has a white head with a red stripe on the back. Thorax is white. The wings are predominantly white in color with black dots on each corner of the cells and a red margin. The wings have branched pulse lines and a starchy surface. The wing-covered upper abdomen is black with large elliptical plots and is colored yellow forming cells. The lower abdomen is white and has fine hairs that fall out easily. A pair of antennas is black. The forelegs are red, white and black. The other legs are white on the top and black on the bottom. The final joints are white and black which form alternating rings. Tip and sole black all over. The larvae are black in color with a lateral crest ...
Read more

Javanese grasshopper (Valanga nigricornis)

Wooden grasshopper or Javanese grasshopper ( Valanga nigricornis ) is an animal species of Acrididae, grasshoppers that have at least 18 subspecies, insects with very wide diversity in color and size, sexual dimorphism in which females are larger in size and paler in color. V. nigricornis in males has a length of 45-55 millimeters and females 15-75 mm. The head is square and green or yellow or brown or black in color. A pair of antennas has a black color. The eyes are large and gray or white or brownish. The hind legs are very large and have a green or yellow or brown or black color, plain or brindle. The limbs have two rows of large and long spines with black tips facing backward. The wings have a length exceeding the belly, a rough surface and are brown or green or yellow or black in color with pulse lines forming spaces filled with black color. The hind wings are rose red which will be visible when flying. Nymphs are pale green or yellow or brown or blackish in color. Javanese gr...
Read more