Metacirolana shijikiensis Nunomura, 2008

Song, Ji-Hun & Min, Gi-Sik, 2016, New record of two cymothoid isopods (Crustacea: Malacostraca: Isopoda) from South Korea, Journal of Species Research 5 (3), pp. 313-317 : 315-316

2. Metacirolana shijikiensis Nunomura, 2008

ṄmḤḃƞ꼬NAE래ŖmḇNj (ṵAE) ( Fig. 2 ) Synonyms. Metacirolana shijikiensis Nunomura, 2008:

28, figs. 11, 12.

Material examined. Korea: 2♂♂, Gageo­do Island, Sinan­gun , Jeollanam­do, 34°02′N, 125°07′E, June 4 ,

2013, depth 3­5 m, collected using light traps by Lim B.­J.

Diagnosis. Body ( Fig. 2A, B ) flattened, about 3.9 mm, almost 2.3 times as long as wide. Color white in ethanol. Cephalon ( Fig. 2A, B ) 1.7 times as wide as long, with median rostral process. Eyes ( Fig. 2A ) with dark pigment, ommatidia small. Maxilliped ( Fig. 2C ) palp slen­ der, third article expanded and longest. Uropod ( Fig. 2D ) exopod with 12 teeth and marginal setae, spine­like seta is absent; endopod with 22 teeth and marginal setae, spine­like seta is absent. Pleotelson ( Fig. 2E ) triangular, posterior margin serrated, provided with 24 teeth.

Remarks. Metacirolana shijikiensis was described by Nunomura (2008) based on the specimens collected from the Mouth of Shijiki Bay, off Ehonohana, Japan. This species has been previously reported from Japan only. Metacirolana shijikiensis is similar to M. chemola Schotte & Kensley, 2005 in external features. However, M. chemola differs from M. shijikiensis in having two short, stout spine­like setae and simple setae on lateral margin on uropodal exopod and one stout spine­like seta and long simple setae on lateral margin on uropodal endopod (uropodal exopod and endopod with no spine­like setae, but marginal setae in M. shijikiensis ). This species is also similar to M. agaricicola Kensley, 1984 . Howev­ er, M. shijikiensis differs from M. agaricicola in having a convex posterior margin on pleonite 5 (trilobed margin on pleonite 5 in M. agaricicola ). In the original description, the third article of the maxillipedal palp is not expanded and similar length to other articles. We believe that the description of the maxillipedal palp was inaccurate, because all species of the genus Metacirolana have an expanded article 3 on the maxillipedal palp as a generic characteristic ( Brusca et al., 1995). In general, the illustrations and description of M. shijikiensis specimens from South Korea agreed well with the illustrations and original description of Nunomura (2008).

Habitat. There is no information on the habitat at the type locality. The specimens were collected from the sandy bottom with seaweeds at a depth of 3­5 m.

World distribution. Japan ( Nunomura, 2008), Korea.

Deposition. NIBR No. NIBRIV0000437275 (1 male) .

Molecular characteristic. GenBank accession number: KX078776(1 male).

Identifiers. Ji­Hun Song, Gi­Sik Min.

Figures

Fig. 2. Metacirolana shijikiensis, male. A, body, dorsal view; B, body, doral view, drawing; C, maxilliped; D, uropod; E, pleotelson. Scale bars:A, B=1 mm, C, E=0.1 mm, D=0.2 mm.