Hatschekia izenaensis Uyeno & Nagasawa, 2010, n. sp.
Creators: name: Uyeno, Daisuke
name: Nagasawa, Kazuya
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Siphonostomatoida
Hatschekiidae
Hatschekia
Hatschekia izenaensis

description: Hatschekia izenaensis n. sp.
(Figs 45–61)
Type material. Holotype, female (NSMT –Cr 20905), ex Xanthichthys lineopunctatus (Hollard) (Tetraodontiformes: Balistidae), off Izena-jima Island (26°55’N, 127°54’E), the Ryukyu Islands, East China Sea, Japan, 10 April 2008. Paratypes: 2 females (NSMT –Cr 20906), ex X. lineopunctatus, off Izena-jima Island (26°55’N, 127°54’E), the Ryukyu Islands, East China Sea, Japan, 10 April 2008; 2 females (RUMF – ZC–00924), ex X. lineopunctatus, off Izena-jima Island (26°55’N, 127°54’E), the Ryukyu Islands, East China Sea, Japan, 10 April 2008.
Description of female. Body (Figs 45–47) 1436–2145 (1748 ± 305) long, excluding caudal rami (n = 5). Cephalothorax hexagonal, fused to trunk, with distinct suture, slightly shorter than wide [252–323 (276 ± 29) × 273–369 (319 ± 41)], with dorsal, chitinous, trichotomous frame with mid-line extending beyond central point. Trunk sausage-shaped, longer than wide [1186–1829 (1463 ± 279) × 261–508 (364 ± 101)] with constriction in anterior 1/6. Urosome (Fig. 48) excluding caudal ramus shorter than wide [32–49 (38 ± 6) × 87–149 (107 ± 24)]. Genital complex fused to abdomen without border. Caudal ramus (Fig. 48–49) slightly longer than wide [20–23 (21 ± 1) × 11–13 (12 ± 1)], bearing 6 naked setae.
Rostrum without distinct anterior expansion. Antennule (Fig. 50) indistinctly 5-segmented, 110–129 (121 ± 7) long; armature formula: 7, 5, 4, 1, 13 + 1 aesthetasc. Antenna (Fig. 51) 3-segmented; proximal segment (coxa) unarmed; middle segment (basis) ornamented with surface pits; terminal claw bearing with robust, thick, basal process covered with thin membrane; proximal segment length 44–75 (51 ± 13); middle segment length 105–127 (112 ± 9); terminal claw length 24–33 (29 ± 4); total length 174–216 (192 ± 18). Parabasal papilla (Fig. 52) well developed, rod-like, half as long as middle segment of antenna. Oral cone robust. Mandible (Fig. 53) slender, with 6 sharp apical teeth. Maxillule (Fig. 54) bilobate; inner lobe carrying 2 small tapering elements; outer lobe with 1 large and 1 small tapering elements. Maxilla (Fig. 55) 4-segmented; proximal segment unarmed; second segment rod-like, with 1 basal seta; third segment with 1 distal seta; terminal segment small, with bifid claw. Maxilliped absent.
Legs 1 and 2 (Figs 56–57) biramous, with both exopods composed of 2 indistinct segments and 2– segmented endopods; some setae on both rami blunt; leg armature formula as follows:
Protopod of leg 1 ornamented with rows of blunt spinules on anterior surface. Leg 1 (Fig. 56) 67–82 (73 ± 6) long; protopod length 43–51 (47 ± 3); exopod length 22–31 (25 ± 3); endopod length 17–24 (20 ± 3). Leg 2 (Fig. 57) length 67–90 (80 ± 8); protopod length 46–55 (51 ± 4); exopod length 21–35 (28 ± 5); endopod length 22–26 (24 ± 2).
Intercoxal sclerite of legs 1 and 2 (Figs 58–59) bearing 4 processes plus some irregular processes ranging from 1 to 5 in number in different specimens.
Leg 3 (Fig. 60) represented by 2 simple setae originating on anterior ½ of trunk. Leg 4 (Fig. 61) represented by 1 simple lateral seta on posterior ¾ of trunk.
Attachment site. Gill filaments.
Remarks. Hatschekia izenaensis n. sp. shares the 4 processes on the intercoxal sclerites of legs 1 and 2 with 10 species (see remarks of H. hemicyclium) and 3 new species (i.e. H. hemicyclium n. sp., H. jonesi n. sp. and H. kabatai n. sp.). The new species is easily separated from all these congeners by the presence of a variable number of irregular processes on the intercoxal sclerites and by the constriction of the trunk.
Etymology. The name of the new species refers to the type locality, Izena-jima Island.
description: Published as part of 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, pp. 1-40 in Zootaxa 2478 on pages 13-16, DOI: 10.5281/zenodo.195334