Prohatsckekia pseudocremouxi, Moon, Seong Yong, Youn, Seok-Hyun & Maran, Balu Alagar Venmathi, 2016

Moon, Seong Yong, Youn, Seok-Hyun & Maran, Balu Alagar Venmathi, 2016, A new species of Prohatschekia Nunes-Ruivo, 1954 (Siphonostomatoida: Hatschekiidae) from the scorpaenid fish, Scorpaena neglecta Temminck & Schlegel, 1843 (Scorpaeniformes: Scorpaenidae), in Korean waters, Zootaxa 4174 (1), pp. 153-160 : 154-156

Prohatsckekia pseudocremouxi sp. nov.

( Figs. 1–11 )

Type material. Holotype ♀ (dissected and mounted on a glass slide; reg. no. NIBRIV0000266711) and paratype ♀ (preserved in ethanol; reg. no. NIBRIV0000266712), collected from the gills of five specimens of Scorpaena neglecta (Actinopterygii, Scorpaeniformes , Scorpaenidae ), captured north off Jeju Island (33º43’47”N, 126º48’16”E) , Korea, at 102 m depth.

Description of female. Body comprising distinct cephalothorax, short neck region consisting of second and third pedigerous somites, and trunk ( Fig. 1 ). Body ( Fig. 1 ) 1.38 (paratype)–1.45 (holotype) mm long. Cephalothorax ( Fig. 1 ) (253 × 346 µm), 1.36 times wider than long: dorsal cephalothoracic shield with frontal margin produced, slightly concave in mid-line, rounded laterally and well defined posteriorly; shield with conspicuous cuticular strengthening bars visible externally. Parabasal papillae on anterior margin of cephalothorax simple, anteriorly-directed, visible in dorsal view (arrowed in Fig. 1 ). Neck region formed by narrow second and third pedigerous somites, merging into board, slightly dorsoventrally flattened trunk. Trunk ( Fig. 1 ) ovoid (937 × 506 µm), about 1.85 times longer than wide, with swollen posterodistal margins. Abdomen ( Fig. 2 ) wider than long (121 × 153 µm). Caudal rami ( Fig. 1 ) longer than wide (59 × 34 µm), carrying one lateral and five terminal setae. Egg sac ( Fig. 3 ) 1.64 mm long, containing 19 eggs.

Antennule ( Fig. 4 ) 328 µm long, indistinctly 7-segmented; armature formula: 10, 6, 4, 2, 1, 3 + aesthetasc, 9 + aesthetasc. Antenna ( Fig. 5 ) 3-segmented; basal segment unarmed; middle segment elongate, with single seta proximally and entire surface with fine, transverse cuticular ridges; distal segment strongly curved with transverse cuticular ridges in proximal half, subchela with two inner setae, one proximally and one near base of claw. Mandible ( Fig. 6 ) forming stylet with pointed tip, marginal teeth lacking. Maxillule ( Fig. 7 ) bilobate; anterolateral lobe with two small setae; posterior lobe longer, with two long distal setae. Maxilla ( Fig. 8 ) 4-segmented, proximal segment unarmed; second segment largest, with long proximal seta on inner margin; third segment slender, with small distal seta on inner margin; distal segment bearing small inner seta at base of bifid claw. Maxilliped absent.

Legs 1–3 ( Figs. 9–11 ) with coxa and basis largely fused, biramous. Exopods incompletely segmented. Setae on rami usually plumose.

Armature formula as follows: Leg 1 ( Fig. 9 ) exopod indistinctly 2-segmented; endopod unsegmented and ornamented with eight complete and incomplete transverse cuticular ridges on anterior and posterior surfaces. Leg 2 ( Fig. 10 ) exopod indistinctly 2- segmented, proximal segment of exopod with tiny spinules on inner and outer margin, distal segment of exopod with four transverse cuticular ridges on anterior surface; endopod 2-segmented and ornamented with three transverse cuticular ridges, distal segment with eight incomplete transverse cuticular ridges on anterior and posterior surfaces. Leg 3 ( Fig. 11 ) exopod distinctly 2-segmented and ornamented with tiny spinules on inner and outer margins of proximal segment, distal segment with four incomplete transverse cuticular ridges on anterior and posterior surfaces; endopod 2-segmented and ornamented with tiny spinules on inner and outer margin of proximal segment; four transverse cuticular ridges on anterior surface of distal segment. Leg 4 (arrowed in Fig. 1 ) represented by one seta located posteriorly at 2/3 distance along trunk. Leg 5 absent.

Male. Unknown

Etymology. The name of the new species refers to its morphological similarity with Prohatschekia cremouxi Nunes-Ruivo, 1954 .

Figures

FIGURES 1 – 8. Prohatschekia pseudocremouxi sp. nov. (female). 1, habitus, dorsal (right parabasal papilla and setae representing leg 4 arrowed); 2, posterior part of trunk and caudal rami, ventral; 3, egg sac, dorsal; 4, antennule, dorsal; 5, antenna, dorsal; 6, mandible, dorsal; 7, maxillule, dorsal; 8, maxilla, dorsal. Scale bars: 1, 3 = 200 µm; 2, 4 – 5 = 50 µm; 6 – 8 = 25 µm.

FIGURES 9 – 11. Prohatschekia pseudocremouxi sp. nov. (female). 9, leg 1, dorsal; 10, leg 2, dorsal; 11, leg 3, dorsal. Scale bars = 50 µm.