Journal 
INTRODUCTION
The genus SymmiusRichardson, 1904, is one of among 12 genera belonging to the family Chaetiliidae Dana, 1849. Five species have been recorded in the genus Symmius: S. azumiNunomura, 2008, S. caudatusRichardson, 1904, S. philippinensisPoore, 1991, S. planusNunomura, 1984, S. yamaguchiensisShimomura, 2008 (Poore and Schotte 2015c). The family Chaetiliidae and genus Symmius is new to South Korea.
The genus ColanthuraRichardson, 1902 is one of seven genera belonging to the family Paranthuridae Menzies & Glynn, 1968 that is currently comprises of ten species (Poore and Schotte 2015a). This genus is also new to South Korea.
The genus Synidotea Harger, 1878, is one of 22 genera belonging to the family Idoteidae Samouelle, 1819. Currently, it comprises 61 species (Poore and Schotte 2015b). Two species of Synidotea: S. laevidorsalis (Miers, 1881) and S. hikigawaensisNunomura, 1974 have previously been recorded in South Korea (Kwon 1986).
We provide descriptions of the diagnostic characteristics, illustrations, and partial sequences of the mitochondrial cytochrome c oxidase subunit 1 (CO1) of three species.
MATERIALS AND METHODS
1.Sample collection
The specimens of C. pigmentata and S. nipponensis were collected with light traps from Yokjido Island and Sageunjin- beach in South Korea, respectively. The specimen of S. yamaguchiensis is collected with small dredge from Soyado Island in South Korea. They were preserved directly in 95% ethyl alcohol after collection. All examined specimens were deposited in the National Institute of Biological Resources (NIBR) and Inha University, South Korea.
2.Morphological analysis
Specimens were observed and dissected under a stereomicroscope (Model SZX-7; Olympus, Tokyo, Japan). Illustrations of appendages were made with a drawing tube connected to a light microscope (Model DM 2500; Leica, X50- 630, Wetzlar, Germany). Drawings of whole bodies were made using a drawing tube attached to a stereomicroscope (Olympus SZX-12). Measurements of appendages and whole body lengths were taken using a stage micrometer (Leica, Germany) and an ocular micrometer.
3.DNA sequencing
The CO1 sequences were determined according to the method used in the Song and Min (2015) with two primers: jgLCO1490 5′-TITCIACIAAYCAYAARGAYATTGG-3′ and jgHCO2198 5′-TAIACYTCIGGRTGICCRAARAAY CA-3′ (Geller et al. 2013).
RESULTS AND DISCUSSION
Order Isopoda Latreille, 1817 등각목 Family Chaetiliidae Dana, 1849 두엽벌레과 (신칭) Genus SymmiusRichardson, 1904 창벌레속 (신칭)
1.Symmius yamaguchiensisShimomura, 2008 야마구치창벌레 (신칭) (Fig. 2)
Synonyms: Symmius yamaguchiensisShimomura, 2008: 61, figs. 2-5.
Material examined: Korea: 2 females (NIBRIV00003161 48, NIBRIV0000316149), Soyado Island, Incheon-si, 37° 12′N, 126°10′E, Sep 21 2012, depth 0.5~1 m, collected with small dredge by Song JH (Fig. 1).
Diagnosis: Body elongate, 2.4 times as long as wide, dorsoventrally flattened, length 12.35 mm. Eyes small, situated ocular lobes. Head, pereonites and pleonite 2 with middorsal projections. Coxal plates large and distinctly visible dorsally on pereonites 5~7. Pleon 0.42 of total length, composed of 2 segments and pleotelson, pleonite 1 without middorsal projection. Pleotelson triangular, tapering to sharply rounded apex.
Remarks: Symmius yamaguchiensis was described by Shimomura (2008) based on the specimens collected from the off Yamaguchi Prefecture, Japan. This species has been previous reported from type locality only. Symmius yamaguchiensis has a similar external appearance as Symmius caudatusRichardson, 1904. However, S. yamaguchiensis differs from S. caudatus in having wider body (2.5 times as long as wide in S. yamaguchiensis versus 3.1 times as long as wide in S. caudatus) and pereonites 1~7 with mid-dorsal projection (pereonites without mid-dorsal projection in S. caudatus).
In general, S. yamaguchiensis from the South Korea is well agreed with the original descriptions and illustrations of Shimomura (2008). However, Korean specimen has some variation from those of type locality in the following characteristics: (1) anterior angle of ocular lobe slightly projecting anteriorly; (2) maxillipedal endite with two coupling hooks. As a result of this study, distribution of S. yamaguchiensis is more widened, and provides information of genus Symmius from South Korea for the first time.
Habitat: There is no information on habitat at the type locality. This species collected from the South Korea on sandy bottom with sea grass community at 0.5~1 m depth.
World distribution: Japan (Shimomura 2008), Korea.
Deposition: NIBR No. NIBRIV0000316148, NIBRIV0000 316149 (2 females).
Molecular characteristic: GenBank accession number: KR493001, KR493002 (2 females).
Identifiers: Ji-Hun Song, Gi-Sik Min.
2.Symmius azumai Nunomura, 2008
Synonyms: Symmius yamaguchiensisShimomura, 2008: 15, figs. 2, 3.
3.Symmius caudatusRichardson, 1904
Synonyms: Symmius caudatusRichardson, 1904: 39, figs. 11-15.
4.Symmius philippinensisPoore, 1991
Synonyms: Symmius philippinensisPoore, 1991: 149, figs. 7, 8.
5.Symmius planus Nunomura, 1984
Synonyms: Symmius planus Nunomura, 1984: 60, figs. 3, 4.
Family Paranthuridae Menzies & Glynn, 1968 오목꼬리마디벌레과
Genus ColanthuraRichardson, 1902 배마디벌레속 (신칭)
6.C olanthura pigmentata Kensley, 1980 깜장배마디벌레 (신칭) (Fig. 3)
Synonyms: Colanthura pigmentata Kensley, 1980: 5, figs. 2, 3; Poore, 1981: 70; Poore, 1984: 708.
Material examined: Korea: 3 males, 5 females, Yokjido Island, Tongyeong-si, Gyeongsangnam-do, 34°38′N, 128° 14′E, September 10, 2012, depth 2~3 m, collected with light traps by Song JH (Fig. 1).
Diagnosis: Body with dark brown pigmentation, almost 8 times longer than greatest width, 4.8 mm. Pereonite 7 very short and seventh pair of pereopod absent. Pleonites 1~6 free, pleonite 1 about twice length of pleonite 2; pleonites 2~5 subequal; pleonite 6 longer, with a middorsal cleft on posterior margin. Palm of pereopod 1 with proximal triangular process. Pleotelson with no serration.
Remarks: Colanthura pigmentata is distinguished from other species of Colanthura by several characteristics: (1) distinct projection on pereonites 1~5 lateral margin in male specimens; (2) body with dark brown pigmentation; (3) uropodal exopod and endopod with serrate margin; (4) rostrum equal in extent to anterolateral angles of cephalon. Colanthura pigmentata is very similar to C. nigra Nunomura, 1975 in external features. However, the serrate margin on pleotelson is absent in C. pigmentata, while present in C. nigra. Additionally, C. pigmentata has a strong triangular proximal process on pereopod 1, while no proximal process on pereopod 1 in C. nigra (Nunomura and Nishimura 1975; Kensley 1980). In general, C. pigmentata specimens from South Korea are well agreed with the illustrations and original description of Kensley (1980).
Habitat: Habitat information is not available for the type locality. Korean specimens were collected on sandy and gravel bottom with some green algae at 2~3 m depth.
World distribution: Madagascar (Kensley 1980), Korea.
Deposition: NIBR No. NIBRIV0000307755 (1 female).
Molecular characteristic: GenBank accession number: KR095339 (1 female).
Identifiers: Ji-Hun Song, Gi-Sik Min.
Family Idoteidae Samouelle, 1819 주걱벌레과 Genus Synidotea Harger, 1878 둥근주걱벌레속
7.S ynidotea nipponensis Nunomura, 1985 일본둥근주걱벌레 (신칭) (Fig. 4)
Synonyms: Synidotea nipponensis Nunomura, 1985: 127, figs. 5, 6.
Material examined: Korea: 5 females, Sageunjin-beach, Gangneung-si, Gangwon-do, 37°48′N, 128°53′E, July 4, 2014, depth 2~3 m, collected with light traps by Song JH (Fig. 1).
Diagnosis: Body flattened, about 3.4 times as long as wide. Anterior margin of cephalon straight. Pereonites 1~3 with emarginated margin, but 4~7 with parallel margin. Pleotelson with an incomplete suture. Color dull yellow or grey. Posterior margin of pereonite 1 is hardly emarginated and lateral margins of pereonites 4~7 are rounded.
Remarks: Synidotea nippponensis is very similar to S. hikigawaensisNunomura, 1974 in external features. However, S. nipponensis differs from S. hikigawaensis in the relative length of pereopods and the shape of pereonites. Pereopods 2~7 are long, especially pereopod 7; posterior margin of pereonite 1 is hardly emarginated; lateral margins of pereonites 4~7 are rounded (S. nipponensis). Pereopods are short; posterior margin of pereonite 1 is very emarginated; lateral margins of pereonites 4~7 are angulated (S. hikigawaensis).
In general, S. nipponensis specimens from South Korea are well agreed with the illustrations and original description of Nunomura (1985).
Habitat: Habitat information is not available for the type locality. South Korean specimens were collected from a sandy bottom with numerous algae at 1~2 m depth.
World distribution: Japan (Nunomura 1985), Korea.
Deposition: NIBR No. NIBRIV0000307759 (1 female).
Molecular characteristic: GenBank accession number: KR095340 (1 female).
Identifiers: Ji-Hun Song, Gi-Sik Min.
8.S ynidotea hikigawaensis Nunomura, 1974 히키가와둥근주걱벌레
Synonyms: Synidotea hikigawaensis Nunomura, 1974: 9, figs. 6, 7.
9.Synidotea laevidorsalis (Miers, 1881) 둥근주걱벌레
Synonyms: Edotia hirtipes var. laevidorsalisMiers, 1881
Synidotea laevidorsalis (Miers, 1881): Benedict, 1897: 404; Kwon, 1986: 117, fig. 8A.
Key to the Korean species of the genus Synidotea 1. Pleotelson shorter than one and a quarter times the proximal width···················································S. laevidorsalis - Pleotelson longer than one and a half times the proximal width·················································································2
2. Pereonite 1 with very emarginated margin; pereonites 4~7 with angulated margin····················S. hikigawaensis - Pereonite 1 with hardly emarginated margin; pereonites
4~7 with rounded margin···························S. nipponensis
