Two new species of Pseudocrangonyx (Amphipoda: Pseudocrangonyctidae) from the hyporheic zones in South Korea.

Pseudocrangonyx Akatsuka & Komai, 1922, is the most diverse group of subterranean amphipods in the groundwater communities of Far East Asia and is related to the biogeographic origin and evolution of subterranean amphipod fauna in the region. In this study, we describe two new subterranean species of pseudocrangonyctid amphipods, P. seomjinensis sp.

A new species of (Annelida, Opheliidae) from the Yellow Sea of South Korea.

Background: Ehlers, 1897 is a genus of Opheliidae characterised by the body divided into three distinct regions, modified parapodia in chaetiger 10 and a ventral groove restricted to the posterior half of the body. To date, 18 species have been described in the genus. Amongst them, six species have been recorded in northeast Asia.

sp. nov., a new monogonont rotifer with a large epipharynx from Korea (Rotifera, Proalidae).

Background: The family Proalidae Harring & Myers, 1924, includes four genera and 53 species, distributed across all eight biogeographic realms and inhabiting various environments, including freshwater, saltwater and terrestrial environments. The genus , the largest within Proalidae, encompasses 41 species characterised by diverse morphological traits. In Korea, the presence of Proalidae has been documented with five known species: Wilts, Martínez Arbizu & Ahlrichs, 2010, (Milne, 1886), (Bryce, 1897), Wulfert, 1937 and (Collins, 1872).

Description of Conchophthirus sinanodontae n. sp. (Ciliophora: Scuticociliatia), a new endocommensal ciliate of the freshwater mussel Sinanodonta woodiana from Korea.

The morphology and molecular phylogeny of a new ciliate, Conchophthirus sinanodontae n. sp., which was discovered in the freshwater mussel Sinanodonta woodiana (Lea, 1834) from the Chilsancheon River, Buyeo-gun, South Korea, were investigated.

The first report of Bathynellacea in the subterranean water of Mongolia: A new species of Camacho, 2020 (Crustacea, Bathynellidae).

Background: We report the first finding of Bathynellacea, discovered in Mongolia. We also report a new species of the genus Camacho, 2020, which was previously recorded only in the western edge of Russia.

New Information: sp.

The complete mitochondrial genome of a marine polychaete, cf. (Annelida: Spionidae).

Malmgren 1867 is one of the abundant genera of the family Spionidae Grube, 1850. Despite its rich diversity, information on their complete mitochondrial genome has remained unknown. In this study, we determined the complete mitochondrial genome of a spionid polychaete, cf.

A new species of the genus (Rotifera, Monogononta) from Korea, with reports of four additional cephalodellid species.

A new monogonont rotifer, , was described from a soil sample collected in Korea. The new species is morphologically similar to but is distinguished by having two frontal eyespots, a vitellarium with eight nuclei, and the shape of its fulcrum. We also described four other cephalodellid species collected in Korea; , , , and .

Strongylidium koreanum n. sp. (Protozoa: Ciliophora), a new soil species from South Korea.

Strongylidium koreanum n. sp., a new soil ciliate from Jeju Island, South Korea, is described based on live observations, protargol impregnation, and molecular analysis of the 18S rRNA gene sequence.

A new species of (Crustacea, Amphipoda, Gammaridae) from South Korea.

A new species of freshwater gammarid, , was collected from Somaemuldo Island, South Korea. This new species is morphologically characterised by the absence of calceoli in antenna 2, absence of anteroproximal setae on bases in pereopods 6 and 7, outer ramus in uropod 3 with plumose setae on both margins, and a small terminal article of the outer ramus, which is shorter than adjacent spines. A description of the new species and morphological differences from related species are provided in the text.

 sp. nov., a new spionid species (Annelida, Spionidae) from the Korea Strait.

A new spionid polychaete, , was discovered in the fine sandy sediments of an intertidal habitat from Korean waters. The new species is considered a simultaneous hermaphrodite, but no brooding embryos were found in any of the specimens collected in this study. This species is unique in the absence of ciliation in the anteriormost chaetigers.

Morphology and molecular phylogeny of Keronopsis koreana n. sp. (Ciliophora, Hypotricha), a new soil species from South Korea.

The morphology and molecular phylogeny of a new soil ciliate, Keronopsis koreana n. sp., which was discovered in soil from Jindo-gun, South Korea, were investigated.

A New Polychaete, () sp. nov. (Annelida: Spionidae), from Korea.

A new spionid polychaete, () sp. nov., from an intertidal mud flat in Korean waters, is reported.

Eobathynella gwangjuensis sp. nov., a new species of Parabathynellidae (Crustacea, Bathynellacea) from South Korea.

A new species of Parabathynellidae (Crustacea, Bathynellacea) was found in the interstitial groundwater of the Yeongsangang River in South Korea. The new species belongs to the genus Eobathynella Birstein and Ljovuschkin, 1964, which previously comprised six species, including two from South Korea. Eobathynella gwangjuensis sp.

Two new species of feather mites (Acariformes, Astigmata) from the black-tailed godwit, (Charadriiformes, Scolopacidae), in Korea.

Two new species of feather mites are described from two individuals of the black-tailed godwit, (Linnaeus, 1758), in Korea: Alloptes (Conuralloptes) neolimosae (Analgoidea, Alloptidae) and (Pterolichoidea, Syringobiidae). Males of A. (C.

Two new Scolelepis species (Annelida: Spionidae) from the Yellow Sea in Korea.

Two new spionid polychaetes of the genus Scolelepis from the intertidal habitats of the Yellow Sea in Korea are described and illustrated. Scolelepis (Parascolelepis) anterobranchiata sp. nov.

Changes in Fecal Pellet Microbiome of the Cold-Adapted Antarctic Copepod Tigriopus kingsejongensis at Different Temperatures and Developmental Stages.

Tigriopus kingsejongensis, a copepod species reported from the King Sejong Station, Antarctica, serves as a valuable food resource in ecosystems. We cultured T. kingsejongensis at three different temperatures (2 °C, 8 °C, and 15 °C) in a laboratory to observe the changes in its fecal pellet microbiome depending on the cultivation temperatures and developmental stages.

New species of the genus (Annelida, Spionidae) from the southern and western coasts of Korea.

A new spionid polychaete, , is described from the southern and western coasts of Korea. This new species differs from its congeners by the combination of the following morphological characteristics: the presence of orange-brown pigmentation on the anterior part of the prostomium, black pigmentation on the peristomium and along the body, U-shaped nuchal organs, a comparatively long extension of metameric dorsal ciliated organs, three pairs of white dots per chaetiger, two to three posterior abranchiate chaetigers, and the presence of tridentate neuropodial hooded hooks. The partial 16S ribosomal DNA (rDNA) and nuclear 18S rDNA sequences of the new species and sp.

Feather mites (Acariformes, Astigmata) from marine birds of the Barton Peninsula (King George Island, Antarctica), with descriptions of two new species.

We report on the first investigation of feather mites associated with birds living on the Barton Peninsula (King George Island, Antarctica). We found seven feather mite species of the superfamily Analgoidea from four host species. Two new species are described from two charadriiform hosts: Alloptes (Sternalloptes) antarcticus (Alloptidae) from Saunders (Stercorariidae), and (Xolalgidae) from (Gmelin) (Chionidae).

The complete mitochondrial genome of (Annelida: Polychaeta: Spionida).

In this study, the complete mitogenome sequence of Korean was determined. This is the first complete mitogenome in the order Spionida. The complete mitogenome of is 17,561 bp in length with 12 protein-coding genes ( gene absent), 23 transfer RNAs, 2 ribosomal RNAs, and 1 control region.

A new species of (Crustacea, Bathynellacea, Parabathynellidae) from South Korea.

A new parabathynellid bathynellacean species, , was found in the groundwater of the Geumgang River in South Korea. This is the first report of from a tributary of the Geumgang River. All previously-reported species were found in the Hangang River and the origins of the two rivers are distinct from each other.

Antarctic population of Anteholosticha sigmoidea (Foissner, 1982) Berger, 2003 (Ciliophora: Urostylidae) with notes on its phylogenetic position.

Anteholosticha sigmoidea (Foissner, 1982) Berger, 2003 was isolated from a wet soil sample collected on King George Island, Antarctica. Morphological observations and molecular phylogenetic analyses based on the gene sequences of small subunit ribosomal RNA (18S rRNA) were used to identify the species. Anteholosticha sigmoidea can be divided into two groups: group I (three populations described by Foissner 1982) and group II (described by Foissner 1984) based on the morphological differences.

Three new species of subterranean amphipods (Pseudocrangonyctidae: ) from limestone caves in South Korea.

Akatsuka & Komai, 1922 is the most diverse group of subterranean amphipods in the groundwater communities of Far East Asia. In Korea, the diversity of the group has been underestimated due to the records of morphological variants of Uéno, 1934. To estimate the species diversity, we analyzed the morphological characteristics and conducted molecular analyses of specimens collected from Korean caves that we treated as morphological variants of .

Complete mitochondrial genome of (Crustacea: Amphipoda: Pseudocrangonyctidae).

The complete mitochondrial genome of a subterranean pseudocrangonyctid amphipod, , was determined in this paper. The complete mitogenome of . was 14,814 bp in length with the typical 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs, and a control region (CR).

The complete mitochondrial genome of () (Crustacea: Amphipoda: Anisogammaridae).

We determined the mitogenome sequence of () Morino, 1993, which is the first complete mitogenome sequence in the family Anisogammaridae Bousfield, 1977. The complete mitogenome of . (.