Two new temporary ectoparasitic isopods (Cymothoida: Cymothooidea) from Korean waters with a note on geographical distributions of Rocinela Leach, 1818 and Gnathia Leach, 1814.

Two new species of temporary ectoparasitic isopods, Rocinela excavata sp. nov. and Gnathia obtusispina sp. nov., are reported from the southern Islands of the Korean Peninsula. Rocinela excavata sp. nov. is distinguishable from its related species by the following characteristics: (1) laterally stepped rostrum; (2) separated eyes; (3) propodal blade having eight robust setae; and (4) merus having four or five blunt robust setae in pereopods 1-3. Gnathia obtusispina sp. nov. differs from its congeners by the combination of the following characteristics: (1) body covered with numerous tubercles and setae, (2) cephalon having tooth-like paraocular ornamentations; and (3) frontal border having two inferior frontolateral processes. These two new species are the 13th Rocinela species and 19th Gnathia species in the temperate Northern Pacific region, respectively. Discovery of these new species represents high species diversity of the genera Rocinela Leach, 1818 and Gnathia Leach, 1814 worldwide as well as in the Northern Pacific region. In addition, faunal diversity analysis on the members of both genera revealed that Rocinela species show high-latitude diversity whereas Gnathia species have low-latitude diversity.

Taxonomic review of the genus Stenocaris Sars (Copepoda, Harpacticoida, Cylindropsyllidae), with (re)descriptions of two Stenocaris species from the Far East.

The taxonomic concept of the genus Stenocaris Sars, 1909 is uncertain because none of the synapomorphies for the species of Stenocaris are defined. Detailed comparison of previous records of Stenocaris minor (T. Scott, 1892) from different localities reveals that this species represents a species complex composed of two species, S. minor s. str. and S. minor sensu Cottarelli & Venanzetti, 1989. Because the latter species has fundamental differences in the nature of the fifth leg in females and the sexual dimorphism of the second leg in males, we propose a new species for S. minor sensu Cottarelli & Venanzetti, 1989, S. figaroloensis sp. nov. We also suggest that S. minor sensu Apostolov, 1971, S. minor sensu Marinov, 1971, and S. minor sensu Apostolov & Marinov, 1988 from the Black Sea and S. minor sensu Wilson, 1932 from North America should be relegated to species inquirenda in the genus. Taxonomic review of the morphology of all Stenocaris species indicated that the generic concept must be restricted to accommodate S. minor s. str., S. gracilis Sars, 1909, S. intermedia Itô, 1972, S. figaroloensis sp. nov., and the South Korean new species, S. marcida sp. nov., based on the synapomorphic condition of the confluent fifth leg in males. As a result of our analysis, two Stenocaris species, S. baltica Arlt, 1983 and S. pygmaea Noodt, 1955, are transferred to the genus Vermicaris Kornev & Chertoprud, 2008 as V. baltica (Arlt, 1983) comb. nov. and V. pygmaea (Noodt, 1955) comb. nov. based on the synapomorphic characters of a reduced condition of the second and fifth legs. Additionally, S. arenicola Wilson, 1932 and S. kliei (Kunz, 1938) are allocated to a new genus, Huysicaris gen. nov., mainly characterized by obvious caudal rami with a recurved dorsal spinous process and convex inner margins, as H. arenicola (Wilson, 1932) comb. nov. and H. kliei (Kunz, 1938) comb. nov. A marine interstitial harpacticoid collected from the subtidal substrate off Dok-do Island in the East Sea of South Korea is proposed as S. marcida sp. nov. and the distribution of S. intermedia, originally known from its type locality in Japanese waters only, is extended to the East Sea of Korea and Russia. We provide their detailed descriptions and illustrations and discuss the morphological characters supporting their identities.

Two new species of the genus Joeropsis Koehler, 1885 (Isopoda, Asellota, Joeropsididae) from Korean waters.

Two new species, Joeropsisdenticulatus sp. nov. and Joeropsissemicircularis sp. nov. are reported from South Korea. Joeropsisdenticulatus sp. nov. can be identified by the following character states: whole body has dark brown chromatophores dorsally, lateral margins of the cephalon are smooth and narrowing anteriorly, and basis of pereopods has serrated cuticular scales superiorly. Joeropsissemicircularis sp. nov. can be identified by the following character states: the cephalon, pereonite 4, and pleotelson have dark brown chromatophores dorsally, lateral margins of the cephalon are smooth and parallel each other, and flagellar article 1 of the antenna is swollen and semi-circular in shape.

Description of two new janirid isopods (Isopoda, Asellota, Janiridae) from Korean waters.

Two janirid isopods, Caecijaera ciliata sp. nov. and Janiralata truncata sp. nov., are reported from Korean waters in this study. Caecijaera ciliata sp. nov. differs from its congeners by the following features: pereonites 47 with large simple setae on the midline of the posterior tergite margins; the pleotelson is angled proximolaterally; the antennula is six-articled; the basis of pereopod is serrated superiorly; and the appendix masculina is not coiled. Janiralata truncata sp. nov. can be distinguished from its related species by the following characteristics: the lateral margin of the cephalothorax has an acute projection anterolaterally; all coxal plates of the pereonites are visible dorsally; male pleopod has a pair of small rounded projections distally near the fusion line of the two first pleopods; the exopod of pleopod has two plumose setae on the distomedial margin.

Four new species of isopods (Crustacea, Isopoda) from South Korea.

Four new isopods, Amakusanthura intermedia sp. nov., Apanthura laevipedata sp. nov., Idarcturus trispinosus sp. nov., and Neastacilla paralongipectus sp. nov., are reported from the sublittoral zones in Korean waters. Amakusanthura intermedia sp. nov. differs from its congeners by the following features: the uropodal exopod is sinuous distally and with pointed apex; the maxillipedal endite is present and reaching to the distal end of fused palp articles I and II; and the propodal palm of pereopod I is stepped. Apanthura laevipedata sp. nov. can be distinguishable from its related species by the following characteristics: the eye is lacking; the propodal palm of pereopod I is not stepped; and the uropodal exopod is not sinuous. Idarcturus trispinosus sp. nov. is diagnosed by the following features: the cephalon has three dorsal spines and a pair of lateral spines; pereonite IV has two pairs of small dorsolateral spines, four pairs of dorsal spines, and one posterior spine; and the pleotelson has three pairs of wings laterally. Neastacilla paralongipectus sp. nov. can be distinguished by the following characteristics: the body is smooth and lacking dorsal spines or tubercles; pereonite IV is approximately 5.4× longer than pereonites II and III together; and the pleotelson has two pairs of lateral wings. In this paper, detailed descriptions and illustrations of the four species are presented. A key to the genera of the family Arcturidae and keys to the species of the four genera are also provided.

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

A new spionid polychaete, Spiopigmentata sp. nov., 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 Spio sp. 2 reported by Abe and Sato-Okoshi (2021) from Japan showed high similarity, indicating that these two specimens belong to the same species. A detailed description and illustrations of the new species, together with molecular information, are provided.

Neoamphitrite undevigintipes, a new terebellid species from South Korea (Annelida, Terebellida, Terebellidae).

A detailed description and illustrations of a new terebellid species are provided, and molecular information based on partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene are included. The new species, Neoamphitrite undevigintipes sp. nov., is described from the deep sea off the eastern coast of South Korea. It is similar to Neoamphitrite groenlandica (Malmgren, 1866) in that the thorax has 19 notopodial chaetigers. However, Neoamphitrite undevigintipes sp. nov. is clearly distinguishable from N. groenlandica in having the uncini of the first abdominal chaetiger arranged in a single row and in having 12 ventral shields. A taxonomic key to all known Neoamphitrite species is also included.

Two new species of idoteid isopods (Crustacea, Isopoda, Idoteidae) from Korea.

Two new species, Cleantiella ampliscutula sp. nov. and Pentias pluriarticulatus sp. nov., are reported from Korean waters with keys to all known species of the genera Cleantiella and Pentias. Cleantiella ampliscutula sp. nov. can be distinguished from its congeners by the following characteristics: the body is relatively small; pereonite 1 is expanded anterolaterally; coxal plates 2-7 are triangular; the pleon has three partial sutures; the pleotelson is widening posteriorly on the lateral margin; the flagellum of the antenna is single-articled; and the maxillipedal palps are four-articled. Pentias pluriarticulatus sp. nov. can be distinguishable from its congeners by the following characteristics: the lateral margins of the body are parallel; the anterior margin of the cephalon is slightly concave and has a small median notch; the coxal plates are invisible dorsally on pereonites 2-4, but visible on pereonites 5-7; the pleon has three partial sutures; the flagellum of the antenna is composed of nine articles; and the distal ends of the uropodal endopods are sinuous.

Five new subterranean amphipods of the genus Pseudocrangonyx from Korea (Crustacea, Amphipoda, Pseudocrangonyctidae).

Although the majority of the species belonging to the genus Pseudocrangonyx Akatsuka & Komai, 1922 are found among the subterranean fauna of eastern Asia, the taxonomic knowledge is very poor and only four species have been recorded in Korea. In this study, the morphology of the stygobitic pseudocrangonyctid amphipods from Korean subterranean waters was examined and five new species were identified: Pseudocrangonyx concavus sp. nov. has a characteristic emarginated posteroventral margin of epimeral plate 3; Pseudocrangonyx gracilipes sp. nov. differs from other pseudocrangonyctids by the slender and elongated pereopods and more produced posterodistal corner of epimeral plate 3. Pseudocrangonyx crassus sp. nov. shows the expanded peduncular articles and a reduced flagellum of antenna 2. Pseudocrangonyx minutus sp. nov. is distinguished by more reduced pleopod articles compare to other pseudocrangonyctids. Pseudocrangonyx villosus sp. nov. has the more setose bases of pereopods 3 and 4. Detailed descriptions and illustrations are presented for these five new species.

Taxonomic study on the photid amphipods (Senticaudata, Corophiida, Photoidea, Photidae) from Korean waters, with descriptions of a new genus and seven new species.

In this paper, seven new species of the family Photidae from Korean waters are described and illustrated in detail. Among them, Exiliphotis petila sp. nov. is a monotype of the newly reported Exiliphotis gen. nov., which is characterized by slenderer and more elongate pereopods 5-7 than those of other genera of the family Photidae. The genus Latigammaropsis is reported for the first time from Korean waters based on the description of Latigammaropsis careocavata sp. nov., which is differentiated from other Gammaropsis group by having weakly sexual dimorphic gnathopods 2, those have simple palmar margins in both sexes. Three new species of Photis are also described: Photis bronca sp. nov., Photis posterolobus sp. nov., and Photis longicarpus sp. nov. The formerly misidentified Photis longicaudata from Japan and China as well as the Korean material could be classified as a new species, P. bronca sp. nov. For that, the syntypes of P. longicaudata were re-examined, and lectotype and paralectotypes were newly designated in this study. Photis bronca sp. nov. is characterized by quadrate tooth on the palmar margin medially on gnathopod 2 in both sexes. Photis posterolobus sp. nov. shows a pointed posterior lobe on the ischium and a well-developed process of the propodus on male gnathopod 2. Photis longicarpus sp. nov. can be distinguished from other species of the genus by very elongate carpus of male gnathopod 1. Two new species belonging to the genus Podoceropsis are also reported: Podoceropsis insinuomanus sp. nov. has a strongly bisinuous palmar margin on male gnathopod 2, and Podoceropsis pseudoclavapes sp. nov. differs from the closely related species of Podoceropsis clavapes by different shape of the palmar margin and shorter dactylus of male gnathopod 2. Additionally, a key to the Korean species of Photidae is provided.

Two new species of Aphelochaeta (Annelida: Polychaeta: Cirratulidae) from Korean waters.

Two new cirratulid polychaetes of the genus Aphelochaeta collected from Korean waters are reported here along with detailed descriptions and illustrations. Aphelochaeta petila n. sp. is readily distinguished from its congeners by the following characteristics: non-expanded anterior and posterior ends of the body; non-moniliform segments in the abdomen; peristomium with three annulations and an indistinct dorsal crest; both the dorsal tentacles and the first branchiae attached on the peristomium; presence of only a pair of branchiae on chaetiger 1; and the ventrum of the thoracic region with transverse dark blue stripes on the chaetigers 6-16 with methyl green staining. Aphelochaeta intinctoria n. sp. is characterized by a combination of the following features: a rounded prostomium; a peristomium with a dorsal crest; a non-expanded thoracic region; dorsal tentacles on the peristomium and the first pair of branchiae on chaetiger 1; and the thoracic region lacking a distinct methyl green staining pattern. These two new species from Korean waters also differ in details of chaetal ultrastructure.

Timareteposteria, a new cirratulid species from Korea (Annelida, Polychaeta, Cirratulidae).

A new cirratulid species, Timareteposteria sp. n., is described from the intertidal habitats of the eastern coast of South Korea. The new species is closely related to Timareteluxuriosa (Moore, 1904) from southern California based on morphological similarity of the branchial and tentacular finalents and the noto- and neuropodial spines. However, T.posteria sp. n. differs from the latter based on the following characteristics: 1) evenly divided peristomium into three annulations; 2) 2-4 neuropodial spines originating in the posterior chaetigers alternated by a few capillaries; and 3) complete shift in branchial finalents located about one-third between the notopodium and the dorsal midline. The new species has a methyl green staining pattern (MGSP) distinct from other Timarete species. Detailed description and illustrations of the new species are provided with molecular information based on the partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI) and 16S ribosomal RNA (16S). This study also includes a key and discussion of known Timarete species from East Asia.

First records of the uristid lysianassoids from Korean waters: redescription of Anonyx abei Takekawa & Ishimaru, 2001 and description of Anonyx exilipes sp. n. (Crustacea, Amphipoda, Uristidae).

The uristid lysianassoids are reported for the first time from Korean waters with a redescription of Anonyx abei Takekawa & Ishimaru, 2001 and the description of Anonyx exilipessp. n.Anonyx abei is characterized by a distinctively small projection of the posterodistal corner on epimeron 3, different from all species of the Anonyx nugax group which share a constriction at the point of insertion of a distal seta on the inner ramus of uropod 2. Anonyx exilipessp. n. is included in the Anonyx laticoxae group characterized by the unconstricted inner ramus of uropod 2. This new species is distinguished from other A. laticoxae group species by the longer and more slender carpus and propodus of pereopod 6, and the non-lobate merus of pereopod 7.

Procaspase-3 activation by a metalloprotease secreted from Vibrio vulnificus.

Vibrio vulnificus is a marine bacterium and a human pathogen capable of causing wound infection and septicemia. We previously showed that the metalloprotease vEP secreted by V. vulnificus activates prothrombin in vitro. To further investigate the ability of vEP to activate other zymogens, we used a mutant form of procaspase-3 which lacks the native cleavage sites as a zymogen. The mutant zymogen was activated by vEP to yield a mature enzyme with a maximum increase in caspase-3 activity of approximately 14-fold in a time-dependent manner. However, the increase started to decline with prolonged incubation and with higher protease concentration as a result of further cleavage of the mature enzyme. Western blot analysis revealed a band of approximately 17 kDa for the cleavage product, which corresponded with the change in caspase-3 activity. The activated procaspase-3 by vEP was also able to cleave poly(ADP-ribose) polymerase in a cell-free system, and was inhibited by Ac-DEVD-CHO, a potent caspase-3 inhibitor. The results presented are the first to demonstrate the in vitro activation of one of the crucial enzymes involved in cell death by a bacterial extracellular metalloprotease.

Vibrio extracellular protease with prothrombin activation and fibrinolytic activities.

A 36 kDa extracellular metalloprotease (designated to as vEP-MO6) was purified and characterized from Vibrio vulnificus sp. strain MO6 24/0. vEP-MO6 cleaved azocasein and a few other proteins such as prothrombin, plasminogen, fibrinogen and Factor Xa, which are associated with the blood coagulation pathway. The enzyme activity of vEP-MO6 was inhibited by EDTA, which was reversed by the addition of excess divalent cations. vEP-MO6 showed little or no activity toward various chromogenic substrates that are specific for other proteases. The cleavage of prothrombin by vEP-MO6 produced active thrombin, as revealed by an activity assay with thrombin-specific chromogenic substrate and Western blot analysis with anti-thrombin antibody. The enzyme also actively hydrolyzed fibrin polymer as well as the cross-linked fibrin. These results suggest that vEP-MO6 is a prothrombin-activating and cross-linked fibrin-degrading enzyme belonging to the metalloprotease family.

A new species of Lagis (Annelida: Polychaeta: Pectinariidae) from Korean waters.

A new pectinariid polychaete, Lagis plurihamus sp. nov., is reported from intertidal habitats in the southern and western coasts of Korea. Lagis plurihamus sp. nov. is clearly distinguished from its congeners by a combination of the following morphological features: the cephalic veil bears usually 10-15 cirri; two pairs of thoracic branchiae are present on the segments 3 and 4; the scaphe is robust with 9-14 delicate scaphal hooks; the scaphal anal flap has a dorsal anal cirrus and fringed margin. Previously described species of Lagis from East Asia, L. bocki (Hessle, 1917) and L. crenulatus Sun & Qiu 2012 together with the newly described species L. plurihamus sp. nov., all have both short, recurved notochaetae with bordered serrations and long, straight notochaetae with fine serrations. We provide detailed description and illustrations with SEM photographs for the new species. A revised key to all Lagis species is also provided with a comparison of the morphological characteristics of them.

Aroui minusetosus, a new species of Scopelocheiridae from Korea (Crustacea, Amphipoda, Lysianassoidea).

A new species, Aroui minusetosussp. n., is recorded from Korean waters with detailed description and illustrations. A new key to all known Aroui is provided. The Korean material of this scopelocheirid is readily assigned to the genus Aroui by the presence of long and distally barbed setae on the outer plate of maxilla 2. This new species is distinguished from congeners by ventrally smooth coxae 1-3 and a setose posteroventral margin of coxa 4, the subchelate gnathopod 2 having a row of four robust setae on its posterior margin (including an elongate single locking seta), and the setation of all appendages which is less dense than in other species. This is the first record of scopelocheirid amphipods from Korean waters.

A new species of Leodice from Korean waters (Annelida, Polychaeta, Eunicidae).

A new eunicid species, Leodice duplexasp. n., from intertidal and subtidal habitats in the eastern coast of South Korea is described. The new species is assigned to the C-2 group, and is similar to Leodice antennata, the type species of the genus, in having the following combination of characteristics: moniliform antennae and palps, bidentate compound falcigers, articulated peristomial and notopodial cirri, pectinate branchiae showing bimodal distribution of branchial filaments, and yellow aciculae. However, L. duplexasp. n. is readily distinguished from L. antennata by the following features: the aciculae are 2-4 in number, with blunt or pointed tips and hammer-headed or bifid tips, and the subacicular hooks are paired in some chaetigers. A detailed description and illustrations are provided for the new species. The validity of the new species is also supported by a genetic comparison using sequences of the mitochondrial cytochrome c oxidase subunit I (COI). A revised key to known Leodice species is provided with a comparison of their morphological characteristics.

A new species of Zosime (Copepoda: Harpacticoida: Zosimeidae) from shallow subtidal habitats in Korea, with notes on the genus.

Zosime destituta sp. nov. is described from shallow subtidal habitats in the southern sea of Korea. The new species is similar to Z. valida Sars, 1919, but differs from it primarily by the lack of an inner seta on the third endopodal segment of the fourth swimming leg. Based on morphological comparison of female character states, the genus Zosime can be subdivided into three provisional groups, anneae-, incrassata-, and typica-group. These groups are distinguished from each other by differences in the antennule, antennary exopod, mandibular rami, armature of swimming legs, fifth leg, and caudal rami. In addition, Zosime incrassata bathybia Bodin, 1968 is removed from its synonymy with Z. incrassata Sars, 1910 and upgraded to species level. An amended key to all known species of Zosime Boeck, 1873 is given, along with a table of all major characters. The present study is the first report of the family Zosimeidae Seifried, 2003 from Korean waters.

A new species of Strongylacron (Copepoda, Harpacticoida, Cletodidae) from intertidal mudflats in the Korean peninsula.

A new species, Strongylacron glabrum sp. n. is described from intertidal mudflats in the Korean peninsula. The new species is assigned to the monospecific genus Strongylacron Gee & Huys, 1996 in accordance with the generic morphological features of the rostrum, antennary exopod, and thoracic legs. However, Strongylacron glabrum sp. n. is clearly distinguished from the type species, Strongylacron buchholtzi (Boeck, 1873), by the naked anterior margin of rostrum, the elongate exopod and endopodal lobe of female P5 approximately 3.5 and 2.7 times as long as width, respectively, and the presence of 8-10 rod-like projections on prosomites. The genus Strongylacron is first recorded from Korean waters by the present study.