• Animal Systematics, Evolution and Diversity
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• v.11 no.3
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• pp.389-408
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• 1995

The complete larval development of Hemigrapsus penicillatus(De Haan, 1835) from hatching to first crab stage was obtained by culture in the laboratory. Under culture conditions with salinity 33.3% , temperature $25^{\circ}C$, and photophase 14/10 h light/dark, the megalopa and the first crab instar were attained in minimum of 18 and 29 days after hatching respectively. Five zoeal stages and a megalopal stage are described and illustrated in detail. Morphological characters of H. penicillatus larvae were compared with those of other members within the subfamily Varuninae. Morphological differences among H. penicillatus, H. sanguineus and H. sinensis in megalopal stage are tabulated.

• Animal Systematics, Evolution and Diversity
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• v.29 no.2
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• pp.152-159
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• 2013

As a result of continuous taxonomic studies on the Korean crabs, two varunid crabs, Hemigrapsus takanoi Asakura and Watanabe, 2005 and Sestrostoma toriumii (Takeda, 1974), are newly reported from Korean waters. Hemigrapsus takanoi, as a sibling species of H. penicillatus, has not been recognized in Korean waters, and this species occurs in the sympatric habitat with H. penicillatus in the Korean peninsula. Sestrostoma toriumii (Takeda, 1974) is associated with thallassinid Upogebia major (De Haan, 1841) and echiuran Urechis unicintus (Von Drache, 1881) as the case of S. balssi (Shen, 1932). The Korean S. toriumii showed smaller size than those mentioned in the original description. Their illustrations and pictures are provided with descriptions, and the distributions of these species in the Korean peninsula are also provided.

• Animal cells and systems
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• v.6 no.2
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• pp.107-123
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• 2002

One ovigerous crab of Hemigrapsus longitarsis (Miers, 1879) was collected in Jeju Island, Korea and their larvae were reared in the laboratory. Five zoeal and one megalopal stages are described and illustrated in detail. Morphology of the zoeas slightly differs from that in the previous record. Within the genus Hemigrapsus, H. longitarsis shows similarity closer to H. sanguineus and H. penicillatus than to H. sinensis based on the zoeal morphology. The zoeas of H. longitarsis can be distinguished from those of the two other species in having a dorsal carapace spine with minute spinules which is naked in H. sanguineus and H. penicillatus. A provisional key is provided to aid the identification of the grapsid zoeas in Korea.

• Animal cells and systems
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• v.3 no.4
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• pp.407-412
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• 1999

The influence of eating habits and food type on the ultrastructural characteristics of the digestive tracts was studied under the scanning and transmission electron microscopes in two crustacean decapods (Hemigrapsus penicillatus De Haan; mud crab, Pinnotheres cyclinus Shen; symbiotic crab). The relative ratio of the length of midgut versus hindgut was 1:1 in the mud crab, but 4:1 in the symbiotic crab. Observation through the scanning electron microscope revealed that the midguts of both species have densely-arranged longitudinal mucosal folds with a smooth surface. In the hindgut of the mud crab, mucosal folds were longitudinally oriented, clusters of two to five spines were observed on the cuticular surface, and the length of the spine in the distal hindgut was longer than that in the proximal portion. In the symbiotic crab, the mucosal folds were irregulary arranged, and numerous rudimentary spinal structures were noted on the cuticular surface. Through observation of a transmission electron microscope, the epithelial cells of the midgut in both species had numerous microvilli, but the length of the microvilli was slightly longer in the mud crab than in the symbiotic crab. The central layer of the basement membrane and the muscular layer of the midgut were more developed in the mud crab than in the symbiotic crab. The thickness of the cuticular layer over the hindgut surface in the mud crab was about 4 times than that of the symbiotic crab.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.535-544
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• 1998

Seasonal variation of the crab community in the eelgrass (Zostera marina) bed in Kwangyang Bay was studied based on the monthly collections through a year of 1994. The crab community in the eelgrass bed was composed of 21 species representing 12 families. The community was dominated by Charybdis Japonica, Telmessus acutidens, Hemigrapsus penicillatus, and Pugettia quadridens. Crabs collected in the study area were primarily small-sized species or early juveniles of large crab species. Most individuals had carapace width smaller than 25 mm except C. japonica and T. acutidens which had maximum carapace width over 85 mm. More than 5 species were collected every month except January and February (4 and 3 species, respectively). The peak abundance occurred in August and low abundances in autumn and winter. Species diversity indices showed that more diverse crabs were collected In spring and summer, and lesser ones in autumn and winter. The crabs in the study area can be grouped into three groups on the basis of their occurrence patterns: resident species, seasonal species, and temporary species. More abundant and more diverse crabs were collected during nighttime than daytime.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.spc1
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• pp.252-258
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• 2006

Thirteen decapod crustaceans of Dokdo Island were identified and classified based on samples collected around Dokdo Island from May 1999 to November 2004. Of the 13 species, 7 were unrecorded from Dokdo Island: Axiopsis princeps, Pagurus angustus, Pagurus japonicus, Pagurus nigrivittatus, Pagurus spina, Portunus trituberculatus, and Hemigrapsus penicillatus. Of these 7 species, Pagurus nigrivittatus and Pagurus spina were new to the Korean decapod fauna. However, P. spina was only reported as the type series from the Pacific coast of northern Japan. Its geographic range now extends to the East Sea. To date, 25 decapod crustaceans (1 caridean, 1 thalassinidean, 11 anomurans, and 12 brachyurans) have been reported from Dokdo Island.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.3
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• pp.177-184
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• 1987

The quantitative mechanics on the sideways walking of the crabs may provide a basic solution for entanglements of the walking legs in gillnets. The gaiting behaviour of the crabs on the flat board and the nettings 10, 16 and 23 mm in mesh size were experimented concerning about stepping positions and times in the laboratory using video set on July, 1984, It was found that the irregular movements of walking crabs in stepping positions and patterns were appeared on the nettings due to the absence of mechanical contact in spite of neural control of compensating, while on the flat surface evolved systematic leg movements. The mean stride length and walking velocity, which were increased with the carapace width on the flat board, as well as the step period and forward by backward stroke time were greater than those values on the netting, not associated with the carapace or the mesh size. Also, the step period and the Phase difference on the nettings revealed larger fluctuation than on the flat board. The joint angles of the walking legs, on the nettings in meropodite-carporodite and thorax-meropodite, which joint was varied especially up to below horizon because of the falling legs through the netting twine, were virtually wider than those on the flat substrate.

• Korean Journal of Ichthyology
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• v.27 no.3
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• pp.205-216
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• 2015

Mobile macrofauna and community structure were studied at the Youngjong tiny tidepools, Incheon, Korea. Samples were monthly collected from February 2010 to January 2011. Mobile macrofauna community comprised a total of 18 species, including 1,122 individuals and 623.6 gWWt. The dominant species were Luciogobius guttatus, Tridentiger bifasciatus, Hemigrapsus penicillatus, Pagurus minutus. The number of species and biomass were low from December to March, and high from April to November. Canonical correspondence analysis revealed that temperature were the most important environmental variables in determining the observed variability in community composition. Species diversity indices ranged from 0.14 to 2.05, and showed the highest value in October 2010. The tide pools provide spawning ground and nursery ground for some fishes and decapods.

• The Korea Journal of Herbology
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• v.39 no.2
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• pp.1-9
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• 2024

Objectives : Paeng-hwal is described as an insect herbal medicine used for digestive diseases in the Dong-ui-bo-gam. The origin of this herbal medicine is limited to several small crabs, such as Helice tridens. These crab species cohabitat in the same environment and share similar morphological characteristics, making it very difficult to distinguish and collect the individual species for use in dietary supplements or herbal medicines. This study was conducted to develop a genetic identification tool for discriminating among these closely related small crab species. Methods : CO1 DNA barcode regions of 15 samples from 6 species of small crabs were analyzed to obtain the individual sequences. To identify the correct species, comparative analyses were carried out using the database of the NCBI GenBank and the NIBR. SCAR primers were designed to develop simple and rapid assay methods using inter-species specific sequences. Optimal SCAR assay conditions were established through gradient PCR, and the limit of detection (LOD) was determined. Results : Six species of small crabs (Helicana tridens, Macrophthalmus abbreviatus, Helicana tientsinensis, Helicana wuana, Chiromantes dehaani, and Hemigrapsus penicillatus), which are distributed as Paeng-hwal, were identified through CO1 sequences analysis. We also developed SCAR markers to distinguish between six small crabs at the species level. Furthermore, we established the optimal PCR assay methods and the LOD of each individual species. Conclusions : The rapid and simple SCAR-PCR assay methods were developed to identify the species and control the quality of herbal medicines for Paeng-hwal based on the genetic analyses of CO1 DNA barcodes.