Hatschekia izenaensis, 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 : 13-16

publication ID	https://doi.org/ 10.5281/zenodo.195334
DOI	https://doi.org/10.5281/zenodo.5693610
persistent identifier	https://treatment.plazi.org/id/03E387F6-B41A-FFA6-91C8-FC171AA0D950
treatment provided by	Plazi
scientific name	Hatschekia izenaensis
status	sp. nov.

Treatment

Hatschekia izenaensis n. sp.

( Figs 45–61 View FIGURES 45 – 55 View FIGURES 56 – 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 View FIGURES 45 – 55 ) 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 View FIGURES 45 – 55 ) 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 View FIGURES 45 – 55 ) slightly longer than wide [20–23 (21 ± 1) × 11–13 (12 ± 1)], bearing 6 naked setae.

Rostrum without distinct anterior expansion. Antennule ( Fig. 50 View FIGURES 45 – 55 ) indistinctly 5-segmented, 110–129 (121 ± 7) long; armature formula: 7, 5, 4, 1, 13 + 1 aesthetasc. Antenna ( Fig. 51 View FIGURES 45 – 55 ) 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 View FIGURES 45 – 55 ) well developed, rod-like, half as long as middle segment of antenna. Oral cone robust. Mandible ( Fig. 53 View FIGURES 45 – 55 ) slender, with 6 sharp apical teeth. Maxillule ( Fig. 54 View FIGURES 45 – 55 ) bilobate; inner lobe carrying 2 small tapering elements; outer lobe with 1 large and 1 small tapering elements. Maxilla ( Fig. 55 View FIGURES 45 – 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 View FIGURES 56 – 61 ) 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 View FIGURES 56 – 61 ) 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 View FIGURES 56 – 61 ) 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 View FIGURES 56 – 61 ) bearing 4 processes plus some irregular processes ranging from 1 to 5 in number in different specimens.

Leg 3 ( Fig. 60 View FIGURES 56 – 61 ) represented by 2 simple setae originating on anterior ½ of trunk. Leg 4 ( Fig. 61 View FIGURES 56 – 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.