• Animal Systematics, Evolution and Diversity
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• v.22 no.2
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• pp.223-229
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• 2006

Two litonotid ciliates collected from the freshwater habitats in Korea were identified as Loxophyllum meleagris ($M\ddot{u}ller$, 1773) and Siroloxophyllum utriculariae (Penard, 1922). The description was based on the observation of living and protargol impregnated specimens, and biometric analysis. Their diagnostic characteristics are as follows. L. meleagris; $163-480\times80-100{\mu}m$ in vivo, body shape lancet or knife-like; dorsal margin with 10-19 extrusome warts; 8-35 macronuclei nodules, like a string of bead; 16-21 somatic kineties on right side (including perioral kinety 2, 3) and 6-11 on left side (including perioral kinety 1); 1 contractile vacuole located at posterior part at diastole stage, extending along the dorsal margin toward anterior end with a single long narrow canal. S. utriculariae; $110-170\times78-150{\mu}m$ in vivo, body shape lancet like; dorsal margin without extrusome warts; 2 macronuclei, spherical; 12-19 somatic kineties on right side, 3-7 on left side (including perioral kinety 1); 2-3 contractile vacuoles, first one located anterior ventrally, second one located posterior dorsally and last one located near posterior end of cell.

• Animal Systematics, Evolution and Diversity
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• v.39 no.1
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• pp.27-33
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• 2023

The specimens collected from five localities during the period from 2004 to 2022 were observed. As a result of this study, Jellyella eburnea was found to be new to the Korean fauna and three membraniporids were reviewed. Two species, Jellyella eburnea and Biflustra grandicella, were redescribed and illustrated with the collected specimens in this study. Membranipora perfragilis from Korea is changed into Biflustra grandicella. Jellyella eburnea is new to the Korean fauna and first reported outside subtropical and tropical seas of the South Pacific and Indo-Pacific Ocean. This fact proves that the seas in Korea are warming. Additionally, Biflustra crenulata reported from the West Sea, South Sea and Jejudo waters of Korea is synonymized into Biflustra okadai. Membranipora irregulata is transferred into the genus Biflustra. Five of Korean membraniporids, Biflustra grandicella, Biflustra irregulata, Biflustra okadai, Jellyella eburnea, and Jellyella tuberculata, are reported in the Korean fauna as a result of this study. The photos taken in the field and by Scanning Electron Microscopy of two species, Biflustra grandicella and Jellyella eburnea, are provided herein.

• Animal Systematics, Evolution and Diversity
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• v.38 no.1
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• pp.14-19
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• 2022

Leptochiton Gray, 1847 is one of the most ancient chiton groups which includes more than 130 species that occur in cold and deep waters worldwide. Due to their small-sized body, they are often confused as juveniles of other chiton species. Moreover, lack of morphological information makes species identification of this group very challenging. To date, only two Leptochiton species(L. fuliginatus and L. rugatus) have been reported from Korean waters. In this study, we found L. hakodatensis(Thiele, 1909) for the first time in Korea and described microscopic morphological characters of valves (tegmentum sculpture), girdle scale, and radula using a scanning electron microscopy (SEM). Leptochiton hakodatensis is morphologically similar to L. fuliginatus and L. rugatus, but differently characterized by having dorso-ventrally rounded (not carinated) intermediate valves, girdle (perinotum) scales sculptured with 4-7 longitudinal ribs, and bicuspid major lateral teeth of radula. In addition to morphological examination, we determined the partial mitochondrial cytochrome c oxidase subunit I(cox1) as a DNA barcode sequence information. This is the first report that describes microscopic characters (tegmentum of valves, girdle structure, and radula) of L. hakodatensis using a SEM. This study provides a morphological basis for describing Leptochiton species and discovery of a "hidden" species of this genus.

• Animal Systematics, Evolution and Diversity
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• v.39 no.3
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• pp.99-113
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• 2023

The nudibranch is one of the most colorful gastropod species found in oceans worldwide. Unlike many other gastropod groups, the nudibranch loses an external shell in the adult stage, but instead develops various chemical defense systems. More than 2,500 nudibranch species have been reported worldwide, and 73 species are currently recorded in Korean waters. In this study, we present morphological descriptions, DNA barcode information of mtDNA cox1 sequence, and taxonomic review for five nudibranch species: Apata pricei (MacFarland, 1966), Doto rosacea Baba, 1949, Janolus toyamensis Baba and Abe, 1970, Polycera abei (Baba, 1960), and Trinchesia sibogae (Bergh, 1905). Of these, we also provide in-depth discussion of taxonomic issue of A. pricei that was previously subdivided into two subspecies, A. pricei pricei and A. pricei komandorica. Our morphological examination and molecular analyses of the mtDNA cox1 sequences indicate that these two subspecies are not taxonomically warranted. The phylogenetic information for the other nudibranch species from mtDNA cox1 sequence analysis is also included, providing a molecular basis for species identification and inferring their local phylogenies within each of the species groups discussed herein.

• Animal Systematics, Evolution and Diversity
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• v.39 no.4
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• pp.176-211
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• 2023

Nine copepod species of the family Artotrogidae Brady, 1880 are described or redescribed from Korea. Included new species are two in the genus Artotrogus Boeck, 1859, one each in the genera Bradypontius Giesbrecht, 1895, Cryptopontius Giesbrecht, 1899, Neopontius Scott T., 1898 and Chejupontius n. gen., and two in the genus Sewellopontius Ummerkutty, 1966. Chejupontius n. gen. resembles Ascidipontius Kim I. H., 1996, Pulicitrogus Kim I. H., 1998, and Sewellopontius in having reduced armature of leg 1, but is distinguished from these and other genera of the family by the large, mediodistally expanded protopod of leg 5 and by a combination of characters exhibited in leg 1 that the first exopodal segment lacks an inner seta, the second exopodal segment lacks an outer spine, the third exopodal segment is armed with three spines plus one to three setae, and the second endopodal segment is armed with a single inner seta. Pteropontius cristatus Giesbrecht, 1895 known previously only from the Mediterranean Sea is redescribed, based on a newly collected specimen from Korea, and P. trimerus Kim I. H., 1996 is removed to the genus Sewellopontius. A short note is given for the epibiotic suctorian Thecacineta calix (Schroder, 1907) which was found attached to the antennule of a new copepod species.

• Animal Systematics, Evolution and Diversity
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• v.39 no.4
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• pp.254-263
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• 2023

Two feather mites, Brephosceles anatina Dubinin, 1951 (Analgoidea: Alloptidae) and Freyana anatina (Koch, 1844) (Pterolichoidea: Freyanidae), have been reported for the first time from the Eastern Spot-billed Duck, Anas zonorhyncha Swinhoe, 1866 (Anseriformes: Anatidae), in Korea. The genera Brephosceles Hull, 1934 and Freyana Haller, 1877 are new records of Korean fauna. The morphology of B. anatina is distinguished from three species of the lambda species group in having legs IV extending the level of setae e2 with the distal end of the tarsus in males, and the incision on the posterior margin of the hysteronotal shield triangular-shaped and distinctly longer than its greatest width in females. Freyana anatina is distinguished from F. nyrocae and F. obliquasetae in having setae ps1 with a rectangle bend in homeomorphic males, and setae ps1 obliquely ovate and divergent, with the inner canal going obliquely across the membranous part of these setae in females. This study provides morphological redescriptions of both feather mite species supplemented with partial sequences of mitochondrial cytochrome c oxidase subunit I(COI), based on specimens collected in Korea.

• Animal Systematics, Evolution and Diversity
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• v.39 no.4
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• pp.264-271
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• 2023

The edible jellyfish Rhopilema esculentum occurs in waters throughout northeastern Asia, including in Korea, China, and Japan. In Korean waters, R. esculentum has appeared in two regions (Gangwha and Muan). Based on the appearance of young medusae and coastal distribution records, these two regions may be key R. esculentum breeding sites. In the present study, we investigate and compare the genetic structure of R. esculentum in the two regions using mitochondrial sequences (16S ribosomal RNA and cytochrome c oxidase subunit I). The genetic diversity of the R. esculentum population at Ganghwa exceeded that of the population at Muan. Despite considerable geographic separation (400 km) between the two regions(Gangwha and Muan), our haplotype network suggests that the Gangwha and Muan populations of R. esculentum are related. The simple and monotonous genetic structure of the Muan population shows that R. esculentum emergence is relatively recent. In contrast, the Gangwha population shows evolution. Moreover, jellyfish of the Gangwha population are genetically diverse and remain constant despite environmental fluctuations in the Han River. The Gangwha area is considered to be the old origin of R. esculentum in Korea.

• Animal Systematics, Evolution and Diversity
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• v.39 no.4
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• pp.272-283
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• 2023

The spider fauna of rice fields, marshes, and reclaimed lands was intensively explored in 2015-2022. During the seasonal survey, six Tibellus spiders were collected; two of them, Tibellus fengi Efimik, 1999 and Tibellus japonicus Efimik, 1999, were new to Korean spider fauna and four of them were identified as new species, Tibellus deokjeok sp. nov., Tibellus gimcheon sp. nov., Tibellus sihwa sp. nov., and Tibellus yeongdong sp. nov.. Four new species are similar to each other and known species in the shape of the genital organ and body appearance in both sexes, but can be distinguished from the other Tibellus members by the shape of embolus, conductor, retrolateral tibial apophysis, and ventral tibial apophysis in male and median septum, receptaculum, spermatheca, and copulatory duct in female. The present study taxonomically describes these six Tibellus spiders with diagnoses, measurements, and morphological photos with a key to the Korean Tibellus species.

• Animal Systematics, Evolution and Diversity
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• v.40 no.1
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• pp.47-67
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• 2024

The bryozoan assemblage from Seogwipo Formation in Jejudo yielded 33 taxa, including seven cyclostomes and 26 cheilostomes. It is the first fossil bryozoans described from the entire Korean peninsula. Five species, Callopora inermis, Tegella horrida, Celleporaria reflexa, Porella rotundirostris, and Rhynchozoon obliquimandibulatum, are new to the Korean bryozoan fauna as both in the Recent and fossil records. Tegella horrida, Celleporella reflexa, Porella donoghueorum, and Leischara subgracilis are notably cold-water species. This suggests that the Seogwipo Formation was primarily deposited in shallow water environment, subject to changesinfluenced by warm-water masses and temporarily impacted by cold currents. Only 33 species from the Seogwipo Formation in Korea, are very poor because the Seogwipo Formation is the only Pleistocene marine deposit in the Korean Peninsula. Eight species previously unknown as fossils worldwide, Tubulipora perforata, Puellina paracaesia, Reginella multipora, Celleporella reflexa, Exochella cryptodontia, Suhius cf. rubescentis, Cheiloporina cf. haddoni, and Jodoella koreensis are found in the Seogwipo Formation. This study is meaningful as it reports the first fossil assemblage of bryozoans from the Korean peninsula.

• Animal Systematics, Evolution and Diversity
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• v.40 no.1
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• pp.21-34
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• 2024

Two arenicolus halacarid species, Actacarus ornatus n. sp. and A. pacificus Bartsch, 1979, are recorded from sandy intertidal sediment along the coast of South Korea. Actacarus ornatus n. sp. closely resembles A. karoensis Abé, 1990, recorded from Japan, in having chaetotaxy of the idiosoma, legs, palps of gnathosoma, and perigenital setae in both males and females. However, it differs from A. karoensis by a slightly convex tectum, the presence of a row of foveae on the mid-ventral surfaces of the anterior epimeral plate and genitoanal plate, and the absence of areolae on both the anterior and posterior dorsal plates as well as microplatelets on the membranous cuticle alongside the anterior and posterior dorsal plates. Actacarus pacificus Bartsch, 1979, which is widely distributed in the Indo-Pacific region, is characterized by separated plates, a truncated tectum, the anterior epimeral plate with four pairs of setae, the posterior epimeral plate with one dorsal and two ventral setae, and three pairs of subgenital setae in males. A comparative analysis of the morphological characteristics of A. pacificus was conducted within regional populations, including the Korean population. Moreover, a key to Actacarus species from the northwestern Pacific, including a new species, is provided. The genus Actacarus is reported for the first time from Korea.