Hatschekia pseudobalistesi, 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 : 34-36

Hatschekia pseudobalistesi n. sp.

( Figs 148–161 )

Type material. Holotype, female ( NSMT –Cr 20918), ex Pseudobalistes fuscus (Bloch & Schneider) ( Tetraodontiformes : Balistidae ), off Henza-jima Island (26°21’N, 127°59’E), Kin Bay, the Ryukyu Islands, North Pacific Ocean, Japan, 6 December 2007. Paratypes: 7 females ( NSMT –Cr 20919), ex P. fuscus , off Henza-jima Island (26°21’N, 127°59’E), Kin Bay, the Ryukyu Islands, North Pacific Ocean, Japan, 6 December 2007; 3 females ( RUMF –ZC–00931), ex P. fuscus , off Henza-jima Island (26°21’N, 127°59’E), Kin Bay, the Ryukyu Islands, North Pacific Ocean, Japan, 6 December 2007.

Description of female. Body ( Fig. 148 ) 770–850 (817 ± 28) long, excluding caudal rami (n = 11). Cephalothorax pentangular with apex, shorter than wide [181–206 (196 ± 8) × 218–248 (237 ± 10)], widest in anterior ½, with dorsal, hexagonal chitinous frame. Trunk longer than wide [586–660 (626 ± 29) × 156–199 (183 ± 13)] with posterior knobs. Urosome ( Fig. 149 ) excluding caudal ramus slightly shorter than wide [43– 61 (49 ± 5) × 46–71 (52 ± 7)]. Genital complex fused to abdomen without border. Caudal ramus ( Fig. 149 ) slightly longer than wide [12–23 (19 ± 3) × 8–12 (10 ± 1)] with 5 naked setae; base inserted in depression in abdomen.

Rostrum with 1 digitiform process at each posterolateral corner ( Fig. 150 ). Antennule ( Fig. 150 ) indistinctly 5-segmented, 147–209 (172 ± 18) long; armature formula: 8, 5, 4, 1, 13 + 1 aesthetasc; proximal segment bearing pointed process on distal posterior margin. Antenna ( Fig. 151 ) 3-segmented; proximal segment (coxa) unarmed; middle segment (basis) ornamented with surface pits; terminal claw with basal seta; proximal segment length 66–86 (75 ± 8); middle segment length 107–153 (139 ± 12); terminal claw length 43–55 (49 ± 4); total length 222–291 (262 ± 19). Parabasal papilla ( Fig. 152 ) bilobate. Oral cone robust. Mandible ( Fig. 153 ) slender, with 6 sharp apical teeth. Maxillule ( Fig. 154 ) bilobate; inner lobe weakly sclerotized, blunt rod-like; both lobes armed with 2 tapering elements. Maxilla ( Fig. 155 ) 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 156–157 ) biramous; both legs with exopod composed of 2 indistinct segments and 2- segmented endopod; leg armature formula as follows:

Leg 1 ( Fig. 156 ) 74–100 (91 ± 8) long; protopod length 34–52 (45 ± 5); exopod length 40–51 (46 ± 4); endopod length 18–26 (21 ± 3). Leg 2 ( Fig. 157 ) length 87–102 (94 ± 5); protopod length 48–60 (53 ± 4); exopod length 37–44 (41 ± 2); endopod length 29–41 (35 ± 4). Protopods and rami of legs 1 and 2 ornamented with semicircular membranes.

Intercoxal sclerites of legs 1 and 2 ( Figs 158–159 ) bearing 4 similar processes.

Leg 3 ( Fig. 160 ) represented by 2 simple setae originating on mid-lateral line of surface of trunk. Leg 4 ( Fig. 161 ) represented by 1 simple lateral seta on posterior ¾ of trunk.

Attachment site. Gill filaments.

Remarks. Hatschekia pseudobalistesi n. sp. has 4 processes on the intercoxal sclerite of legs 1 and 2. In the genus Hatschekia , this character is shared with 10 species (see remarks of H. hemicyclium ) and 9 new species ( H. churaumi n. sp., H. hemicyclium n. sp., H. izenaensis n. sp., H. jonesi n. sp., H. kabatai n. sp., H. mihkagan n. sp., H. mongarah n. sp., H. nakamurai n. sp. and H. zanpa n. sp.). The new species can be differentiated from these species by having an unusual caudal ramus inserted in a depression in the abdomen. It also has a unique antennule with a pointed process on the distal posterior edge of the proximal segment, which is not found in 18 of these species, except for H. ballistae . In the original description of H. balistae ( Nuñes-Ruivo 1954, fig. 11b), the antennule was illustrated with an element on the posterior surface of the proximal segment. However, Hatschekia spp. usually have no such an element so it appears that the element reported by Nuñes-Ruivo (1954) is a process. The new species also shares the presence of an apex on the cephalothorax, and has the same number of setal elements on legs 1 and 2 as H. balistae , but differs from it in the trunk width being shorter than the cephalothorax width.

Etymology. The specific name of the new species, pseudobalistesi , refers to the scientific name of the type fish, Pseudobalistes fuscus .

Figures

FIGURES 148 – 155. Hatschekia pseudobalistesi n. sp., female, holotype NSMT – Cr 20918. 148, habitus dorsal; 149, posterior part of trunk, dorsal; 150, antennule, ventral, rp = rostrum process, pp = pointed process; 151, antenna, ventral; 152, antenna with parabasal papilla; 153, mandible. 154, maxillule. 155, maxilla. Scale bars: 148, 200 μm; 149 – 150, 155, 40 μm; 151 – 152, 100 μm; 153, 10 μm; 154, 20 μm.

FIGURES 156 – 161. Hatschekia pseudobalistesi n. sp., female, holotype NSMT – Cr 20918. 156, leg 1, anterior view; 157, leg 2, anterior view; 158, intercoxal sclerite of leg 1, anterior view; 159, intercoxal sclerite of leg 2, anterior view; 160, leg 3; 161, leg 4. Scale bars: 156 – 157, 40 μm; 158 – 159, 50 μm; 160 – 161, 10 μm.