Hatschekia nakamurai, Uyeno, Daisuke & Nagasawa, Kazuya, 2010

Uyeno, Daisuke & Nagasawa, Kazuya, 2010, The copepod genus Hatschekia Poche, 1902 (Siphonostomatoida: Hatschekiidae) from triggerfishes (Pisces: Tetraodontiformes: Balistidae) from off the Ryukyu Islands, Japan, with descriptions of eleven new species, Zootaxa 2478, pp. 1-40 : 28-30

Hatschekia nakamurai n. sp.

( Figs 119–132 )

Type material. Holotype, female ( NSMT –Cr 20914), ex Melichthys vidua (Richardson) ( Tetraodontiformes : Balistidae ), off Sesoko-jima Island (26°38’N, 127°51’E), the Ryukyu Islands, East China Sea, Japan, 21 May 2005. Paratypes: 1 female ( RUMF –ZC–00929), ex M. vidua , off Sesoko-jima Island (26°38’N, 127°51’E), the Ryukyu Islands, East China Sea, Japan, 21 May 2005; 4 females ( NSMT –Cr 20915), ex M. vidua , off Minna-jima Island (26°38’N, 127°48’E), the Ryukyu Islands, East China Sea, Japan, 25 July 2007.

Description of female. Body ( Fig. 119 ) 926–1174 (1008 ±91) long, excluding caudal rami (n = 6). Cephalothorax hexagonal, shorter than wide [196–212 (206 ± 7) × 221–255 (240 ± 13)], widest in posterior ½, with dorsal, pentangular chitinous frame with mid-line ending immediately before triangular depression. Trunk narrowing posteriorly, curved slightly, longer than wide [721–995 (808 ± 99) × 204–276 (234 ± 24)]. Urosome ( Fig. 120 ) excluding caudal ramus shorter than wide [34–70 (55 ± 13) × 58–84 (75 ± 10)]. Genital complex fused to abdomen without border. Caudal ramus ( Fig. 120 ) ovoid, slightly longer than wide [21–31 (26 ± 3) ×13–22 (17 ± 3)], bearing 5 naked setae.

Rostrum expanded anteriorly on cephalothorax with 1 round process at each posterolateral corner ( Fig. 121 ). Antennule ( Fig. 121 ) indistinctly 5-segmented, 174–185 (180 ± 5) long; armature formula: 10, 5, 4, 1, 13 + 1 aesthetasc. Antenna ( Fig. 122 ) 3-segmented; proximal segment (coxa) unarmed; middle segment (basis) ornamented with surface pits; terminal claw with a basal seta; proximal segment length 48–73 (57 ± 9); middle segment length 103–126 (112 ± 9); terminal claw length 32–49 (41 ± 7); total length 195–225 (210 ± 12). Parabasal papilla ( Fig. 123 ) digitiform, wrinkled. Oral cone robust. Mandible ( Fig. 124 ) slender, with 4 sharp apical teeth. Maxillule ( Fig. 125 ) bilobate; inner lobe highly sclerotized; both lobes armed with 2 tapering elements. Maxilla ( Fig. 126 ) 4-segmented; proximal segment unarmed; second segment rod-like, with 1 basal seta; third segment elongate, with 1 distal seta; terminal segment small, with 1 small seta and bifid claw. Maxilliped absent.

Legs 1 and 2 ( Figs 127–128 ) biramous; both legs with exopod composed of 2 indistinct segments and 2- segmented endopod; leg armature formula as follows:

Leg 1 ( Fig. 127 ) 81–102 (94 ± 8) long; protopod length 40–56 (50 ± 6); exopod length 38–51 (44 ± 5); endopod length 28–37 (32 ± 3). Leg 2 ( Fig. 128 ) length 90–117 (106 ± 10); protopod length 55–72 (64 ± 6); exopod length 35–46 (43 ± 4); endopod length 38–50 (46 ± 5). Protopods of legs 1 and 2 ornamented with rows of blunt spinules on anterior surface. Both rami of legs 1 and 2 ornamented with semicircular membranes.

Intercoxal sclerites of legs 1 and 2 ( Figs 129–130 ) bearing 4 similar processes.

Leg 3 ( Fig. 131 ) represented by 2 simple setae originating on anterior ½ of trunk. Leg 4 ( Fig. 132 ) represented by 1 simple lateral seta on posterior ½ of trunk.

Attachment site. Gill filaments.

Remarks. H. nakamurai n. sp. shares the 4 processes on the intercoxal sclerites of legs 1 and 2 with 10 species (see remarks of H. hemicyclium ) and 7 new species (i.e. H. churaumi n. sp., H. hemicyclium n. sp., H. izenaensis n. sp., H. jonesi n. sp., H. kabatai n. sp., H. mongarah n. sp. and H. zanpa n. sp.). Hatschekia balistae possesses an apex on the cephalothorax not present in the new species. Additionally, the new species bears 10 setae on the proximal segment of the antennule, a character shared with H. churaumi n. sp., H. kabatai n. sp., H. lima , H. pseudostracii , H. sunaoi and H. zanpa n. sp. and the new species has a maxillule with a highly chitinized inner lobe, which is also present on H. lima and H. zanpa n. sp. These species, however, differ from the new species by having leg 3 situated on a conical process.

Etymology. The specific name, nakamurai , is dedicated to Mr. Shigeo Nakamura, a technical officer at the Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, who assisted with collecting the specimens.

Figures

FIGURES 119 – 126. Hatschekia nakamurai n. sp., female, holotype NSMT – Cr 20914. 119, habitus dorsal; 120, posterior part of trunk, dorsal; 121, antennule, ventral, rp = rostrum process; 122, antenna, ventral; 123, antenna with parabasal papilla (drawn from a paratype, NSMT – Cr 20915); 124, mandible; 125, maxillule; 126, maxilla. Scale bars: 119, 200 μm; 120, 122, 30 μm; 121, 40 μm; 123, 50 μm; 124 – 125, 10 μm; 126, 20 μm.

FIGURES 127 – 132. Hatschekia nakamurai n. sp., female, holotype NSMT – Cr 20914. 127, leg 1, anterior view; 128, leg 2, anterior view; 129, intercoxal sclerite of leg 1, anterior view; 130, intercoxal sclerite of leg 2, anterior view; 131, leg 3; 132, leg 4. Scale bars: 127 – 128, 20 μm; 129 – 130, 30 μm; 131 – 132, 10 μm.