Gnathia kuwaitensis, Khalaji-Pirbalouty & Al-Kandari, 2023

Khalaji-Pirbalouty, Valiallah & Al-Kandari, Manal Abdulrahman, 2023, Three new species of temporary fish parasite, Gnathiid Isopods (Crustacea: Isopoda: Cymothoida) from Kuwait, Zootaxa 5383 (1), pp. 24-38 : 33-37

Gnathia kuwaitensis sp. nov.

urn:lsid:zoobank.org:act:FC0C6B1A-B792-4978-A349-366A6FFA58EC

Figs 7–9

Gnathia sp. , Al-Kandari et al. 2022: 118, fig. 3A.

Type material. Holotype. ♂ (2.7 mm); Umm Al-Maradim Island , Kuwait; 28°40.778’N; 48°39.207’E; 11 November 2014, dead coral, 0.5–1 m ( ZMH-K- 63978 ) . Paratypes. 1 ♂ (2.3 mm), 3 praniza larvae; same data as holotype, ( ZMH-K- 63979 ) . 2 ♂♂ (2.2 mm, 2.8 mm); 3 ♀♀ (up to 2.2 mm); 7 praniza larvae (up to 2.5 mm); Umm Al-Maradim Island , northeast; 28°40.939’N; 48°39.196’E; 11 November 2014, dead coral, 1–1.5 m ( ZMH-K- 63980 ) . 1 ♂ (2.8 mm), 2 ♀♀ (1.5 mm); 11 zuphea larvae (up to 1.5 mm); 10 praniza larvae (up to 1.8 mm). 5 ♀♀ (up to 1.8 mm), 13 praniza larvae (up to 2.4 mm), Qaruh Island (north); 28°49.105’N; 48°46.553’E, 10 November 2014, coral rubble, 1–2 m ( ZMH-K- 63981 ). 2 blood-feeding praniza (2.2 mm); Al-Judailiat , 29°22.497’N; 47°45.183’E, 02 February 2014; dead coral, 1–2 m ( ZMH-K- 63982 ) .

Diagnosis of male. Cephalosome 0.8 times as long as wide, supraocular lobe pronounced, blunt and oblique. Mediofrontal process present, conical, which is slightly sunken; superior frontolateral process, pronounced, with median notch distally.

Male description. Body ( Fig. 7 A ) length 2.7 mm, about 3 times as long as greatest wide, widest at pereonite 3. Cephalosome ( Figs 7 A – C , 9 B ), about 0.8 times as long as wide; dorsal surface sparsely setose, with sparse granules; dorsal sulcus narrow, deep, short. Supraocular lobe pronounced, rectangular. Mediofrontal process present, conical with slightly concave apex; superior frontolateral process, pronounced, distally bifid, with 3 fine long setae. Inferior frontolateral process small, serrated. Dorsal sulcus wide, deep, triangular. Eyes lateral, slightly less than one-third of cephalosome.

Pereon lateral margins subparallel, with few long setae, without tubercles on dorsal surface. Pereonite 1 not fused dorsally with cephalosome, not reaching lateral margin. Pereonites 2 and 3 of similar size, wider than pereonite 1, widest part of the body. Pereonite 3 with anterior constriction. Pereonite 4 longer and narrower than pereonite 3, with prominent anterior constriction; median groove absent. Pereonite 5 with areae laterales. Pereonite 6 without lobi laterales; lobuii weak. Pereonite 7 dorsally visible, with rounded posterior margin. Pleonites 1–5 ( Fig. 7 A ), epimera visible dorsally, two pairs of simple setae on each side posteriorly on all pleonites. Pleotelson ( Fig. 7 D ) 0.9 times as long as anterior width, lateral margins smooth; posterolateral margins with 2 submarginal setae, apex terminating in pair of simple setae.

Antennula ( Fig. 7 E ) peduncle article 3 about 1.75 times as long as article 2; flagellum with 6 articles, about 1.1 times as long as peduncle article 3, articles 4–6 each bearing an aesthetasc. Antenna ( Fig. 7 E ) peduncle article 4, about 1.1 times as long article 3; flagellum with 7 articles, about 1.3 times as long as peduncle article 4.

Mandible ( Fig. 7 F ) about 0.68 times as long as cephalosome width, weakly curved, with 9–10 strong denticulations on the dentate blade, with single seta between each denticule. Incisor present, long simple mandibular seta not extending out of the carina.

Maxilliped ( Fig. 7 G ) article 1 external margin fringed with fine, small setae; endite just reaching article 3; external margins of articles 2–5 bearing 4, 6, 5 and 7 stout plumose setae respectively; article 5 with 2 simple setae distally.

Pylopod ( Fig. 7 H ) first article 1.5 as long as wide, lateral margin with 24 large plumose setae, mesial and proximal margins with continuous fine setae, distal end with 2 long simple setae, with 2 acute spines-like process on mesiolateral lobe; article 2 about 1.2 times as long as wide, 0.14 times length of article 1, fringed with dense fine setae, with 3 long simple setae distally, 2 simple setae medially; article 3 minute, with single seta distally.

Pereopod 2 ( Fig. 8 A ) basis 2.5 times as long as greatest width, superior margin with 2 long, 2 sensory palmate setae and 7 tubercles; ischium superior margin with 2 long setae, inferior margin with 3 simple setae and 2 tubercles; merus as long as carpus, inferior margin with 5 simple setae and 2 tubercles, superiodistal corner with 3 long simple setae; carpus inferior margin with 3 tubercles and 1 biserrate robust seta; propodus 3.35 times as long as wide, superior margin with 3 simple and 1 sensory palmate setae, inferior margin with 2 robust serrate setae. Pereopod 3 ( Fig. 8 B ) similar to pereopod 2, as illustrated. Pereopod 4 ( Fig. 8 C ) basis 2.3 times as long as greatest width, superior margin with 2 long, 2 sensory palmate setae and 2 tubercles; ischium superior margin with 2 long setae, inferior margin with 4 simple setae and 3 tubercles; merus inferior margin with 4 simple setae and 4 tubercles, superiodistal corner with 2 long simple setae; carpus inferior margin with 2 tubercles and 3 simple setae; propodus inferior margin with 2 robust serrate setae and 1 tubercle. Pereopod 5 ( Fig. 8 D ) similar to pereopod 6 ( Fig. 7 E ) as illustrated.

Pleopod 1 ( Fig. 8 F ) endopod longer than exopod, about 2.3 times as long as wide, with 7 plumose marginal setae; exopod 1.8 times as long as wide with 8 plumose marginal setae; sympodite mesial margin with 2 coupling hooks. Pleopod 2 ( Fig. 8 G ) endopod and exopod, distally with 9 and 8 plumose marginal setae, respectively. Pleopod 4 ( Fig. 8 H ) endopod and exopod, distally with 8 plumose marginal setae. Pleopod 5 ( Fig. 8 I ) endopod and exopod, distally with 8 and 10 plumose marginal setae, respectively.

Uropodal ( Fig. 7 D ) rami extending well beyond pleotelson apex, endopod wider than exopod, with 9 long plumose marginal setae. Exopod mesial and lateral margins with 10 long plumose setae. Uropodal peduncle with single simple seta distally.

A female, a praniza larva and a zuphea larva are illustrated ( Fig. 9 C – E ).

Distribution. Umm Al-Maradim, Qaruh and Failaka Islands, Al-Judailiat, Kuwait Bay (Ras Ajuza), Masfat AlAhmadi, and Mina Abdullah.

Remarks. The new species resembles G. marleyi Farquharson, Smit & Sikkel, 2012 from the Eastern Caribbean, such as in the shape of the cephalosome and mandible, rectangular supraocular lobes and a conical mediofrontal process which is slightly sunken. It differs, however, from G. marleyi in having distally bifid superior frontolateral processes (conical in G. marleyi ), a pylopod with 24 plumose long setae on mesial border (rather than 30 in G. marleyi ); a maxilliped with 4 plumose setae on external margins of articles 2 (rather than 6 in G. marleyi ). It also has certain similarities to G. luxata Kensley, Schotte & Poore, 2009 from Khawr Musharraba, Saudi Arabia, Persian Gulf. However, G. luxata differs from the new species by having a simply rounded supraocular lobe rather than blunt and oblique, a conical superior frontal process rather than distally bifid; a mandible with pseudoblade, and a cephalosome with 2 crescent-shaped ridges dorsolaterally ( Fig. 7 I ).

Etymology. The epithet is taken from the country of the type locality, Kuwait.

Figures

FIGURE 7. Gnathia kuwaitensis sp. nov. (ZMH-K-63978), male holotype: A, dorsal view; B, dorsal view of cephalosome; C, ventral view of cephalosome; D, dorsal view of pleotelson and uropods; E, antennula and antenna; F, mandible; G, maxilliped; H, pylopod; I, Gnathia luxata Kensley, Schotte & Poore, 2009 (Holotype: USNM 280383) frontal border.

FIGURE 8. Gnathia kuwaitensis sp. nov. (ZMH-K-63978), male holotype: A–E. pereopods 2–6 respectively; F, pleopod 1; G, pleopod 2; H, pleopod 4; I, pleopod 5.

FIGURE 9. Gnathia kuwaitensis sp. nov. Scanning electron micrographs of male from Al-Nuwaiseeb, Kuwait: A, dorsal view; B, dorsal view of cephalosome; male from Umm Al-Maradim Island, Kuawit (C–E): C, female; D, praniza larva; E, zuphea larva.