Oshoroclausia shibazakii n. sp.

(Figs 1–3)

Type material. Holotype female (NSMT –Cr 24117) from sandy bottom off Oshoro Marine Station (43°12′33.30″N, 140°51′31.10″E), Oshoro Bay, Hokkaido, an inlet of the Sea of Japan, 1 m depth, 30 October 2013, leg. K. Kakui.

Description of adult female. Body (Fig. 1A, B) elongate, cylindrical, 5114 long comprising cephalothorax and indistinctly segmented post-cephalothoracic trunk. Cephalothorax longer than wide, 548×387, with projecting rostral area (Fig. 1C) bearing triangular ventral margin and pair of sensory elements (Fig. 1D). Segmentation of second to fifth pedigers, genital complex, and 3-segmented abdomen indistinct. Genital complex 509 at widest point, with paired lateral lobes (Figs 1A, B, 2L). Caudal rami longer than wide 111×54, fused at base to anal somite, bearing one medial, one subterminal, and three small and one long distal setae; all setae naked.

Antennule (Fig. 1F) 3-segmented; proximal segment bearing two lobes; armature formula: 13, 6+1 aesthetasc, 7+1 aesthetasc; all setae naked. Antenna (Fig. 1G) 2-segmented; basal segment unarmed; terminal segment peanutshaped with median crease (Fig. 1H); proximal part covered with fine spinules and distal part bearing rounded protruding lobe covered with fine spinules, three small elements, and small, knob-like distal projection (Fig. 1I) armed with two serrate spines and two simple setae. Labrum (Fig. 2A) triangular, bearing pointed conical posterocentral projection and ornamented with paired patches of fine spinules in basal region. Mandible (Fig. 2B) rod-like, with distal pointed spine. Paragnath (Fig. 2C) rounded, with horizontal concavity, surface covered with hairs. Maxillule (Fig. 2D) with one medial and two distal setae. Maxilla (Fig. 2E) 2-segmented; proximal segment (syncoxa) robust and unarmed; distal segment (basis) bifurcate, bearing patches of fine spinules on each tip and single blunt element on posterior margin. Maxilliped (Fig. 2F) unsegmented, subdivided into large conical basal part with row of spinules on anterior margin and small, claw-like distal part.

Legs 1 to 4 (Fig. 2G–J) biramous with 2-segmented rami; armature formula of legs shown in Table 1. All setae naked. Both rami of legs 1 and 2 and exopod of legs 3 and 4 bearing row of fine setules on outer margin. Intercoxal sclerites of legs 3 and 4 absent. Leg 5 (Fig. 2K) 2-segmented; proximal segment (protopod) fused to pedigerous somite armed with single distal seta; terminal segment (exopod) rod-like, bearing three minute setae on posterior margin and conical tip with basal membranous crescent and apical seta. Leg 6 (Fig. 2L) represented by two simple setae at base of lateral lobe of genital complex.

Coloration in life. Dull red (Fig. 3A, B).

Adult male. Unknown.

Host and habitat. The copepod was found in sediment on a sandy bottom. The host is unknown.

Etymology. The specific name of the new species, shibazakii, was chosen in honor of Mr. Koji Shibazaki, the administrator of the Oshoro Marine Station, Hokkaido University, as a tribute to his constant, devoted support for the many researchers who undertaken fieldwork there.

Newly established Japanese name for the family, the genus and the species. Gokai-mijinko.