Eurydice marzouqui, Jones, David Alan & Nithyanandan, Manickam, 2012

Jones, David Alan & Nithyanandan, Manickam, 2012, Taxonomy and distribution of the genus Eurydice Leach, 1815 (Crustacea, Isopoda, Cirolanidae) from the Arabian region, including three new species, Zootaxa 3314, pp. 45-57 : 47-48

Eurydice marzouqui sp. nov.

( Figs 1 , 4 a–c)

Material examined. Holotype. Male 3.4 mm, ( SMF 34840): sta. 5G-3 Tarut Bay, Saudi Arabia, seagrass beds, coll. J. McCain, 11 June 1984.

Paratypes: 1 male ( SMF 34841): Sabah Al-Ahmad Sea City Waterways, Kuwait, ichthyoplankton, coll. B. R. Sontakke, 12 May, 2008. 2 females ( SMF 34842) sta 7RG off Manifa, Saudi Arabia, seagrass beds, coll. S.M. Ali, Feb. 1986.

Description. Male holotype: Body 2.9 times as long as greatest width at pereonites 4 and 5. Cephalon anterior margin evenly rounded, eyes small with 7 ocelli horizontally and 6 vertically. Coxae 2–7 with acute angles at posterolateral margins. Pleonites of equal length, pleonite 1 slightly concealed by posterior margin of pereonite 7. Ventral margins of pleonites 2–5 acute, posterior dorsal margin of pleonite 5 sinuous, centrally convex. Pleotelson as broad as long, anterior margin 5 times width of posterior margin, which is slightly rounded, and bears 6 apical teeth, 8 simple setae and 6 plumose setae.

Antennule barely reaching mid-point of eye, flagellum of 4 articles, article 1 longer than combined length of articles 2–4. Antenna peduncle reaching to pereonite 1; article 1 with 2 setae on anterodistal angle, article 3 with 3 anterodistal setae; article 4 longer than articles 2 and 3 combined; flagellum of 21 articles reaching posterior margin of pereonite 7; flagellum terminal seta is 0.2 length of flagellum.

Mandible spine row with 5 spines; molar process anterior margin with 14 spines. Terminal article of mandibular palp twice as long as broad, with 8 setae. Maxillule lateral lobe with 13 robust setae on gnathal surface, medial lobe with 3 stout circum plumose setae and 2 simple setae. Maxilla lateral lobe with 3 setae, middle lobe with 3 setae and medial lobe with 3 plumose and 2 simple setae. Maxilliped palp with all articles entire, terminal article with 6 simple setae; endite with 1 plumose and 2 simple setae.

Pereopods 1–3 sparsely setose, pereopod 1 and 3 figured. Pereopod 1 with robust seta opposing dactylus half length of dactylus; posterior margin of ischium with 2 robust setae; merus with single anterodistal robust seta and 2 simple setae. Pereopod 2 similar but with robust seta opposing dactylus only one third length of dactylus. No robust setae on posterior margin of ischium and 3 simple setae only on anterodistal margin of merus. Pereopod 3 with 4 robust setae on the posterodistal margin of propodus and 2 robust setae on posterior margin; merus with 4 posterodistal robust setae; carpus with 3 posterodistal and 2 on the posterolateral margin. Ischium with 3 posterodistal and 2 groups of 2 robust setae on posterior margin; basis with 4 simple setae on posterodistal angle. Pereopod 7 sparsely setose, propodus anterior margin with 6 robust and 1 simple seta; posterior margin with 3 robust and 2 simple setae. Merus with 5 robust and 3 simple setae on anterior margin; posterior margin with 4 robust setae. Carpus with 4 robust and 4 simple setae on anterior margin and 4 robust setae on posterior margin. Ischium with 3 robust and 2 simple setae on anterior margin and 2 robust setae on posterior margin.

Pleopod 1 with rami subequal in length, exopod with 17 plumose setae, endopod with 11, exopod 1.5 times wider than endopod. Pleopod 2 exopod and endopod with 17 and 15 plumose setae respectively. Appendix masculina of even width, distally straight, apex rounded, appendix masculina 0.7 as long as endopod, projects beyond endopod by one tenth of its length. Uropod endopod 1.4 times length of exopod, bearing 9 plumose setae on posterior margin and 5 simple setae on lateral margin. Exopod ovate with 4 simple setae on lateral margin and 6 plumose and 3 simple setae on posterior margin. Both rami do not reach pleotelson posterior margin.

Female: As for male but body broader, antennae shorter reaching posterior margin of pereon segment 5.

Colour. Translucent with black chromatophores on dorsal surface of cephalon, pereon and pleon, extending onto ventrolateral surfaces of pleon.

Remarks. The slightly rounded posterior margin of the pleotelson with 6 equal sized apical teeth and an absence of robust setae, combined with straight appendix masculina, with a blunt unornamented apex, are the characters which diagnose E. marzouqui sp. nov. This is the first subtidal species to be recorded from the Arabian Gulf and it is separated from the intertidal species E. peraticis and E. paxilli by the absence of robust setae on the posterior margin of the pleotelson. The absence of robust setae, together with a narrow posterior pleotelson margin, are common features amongst subtidal Eurydice species, but E. marzouqui may be separated from all others by the number of apical teeth, plumose setae and appendix masculina shape. Only E. tarti Bruce 1986 has a similar rounded apex to the appendix masculina, but in E. tarti the appendix masculina is curved and the posterior margin of the pleotelson is acute. The appendix masculina of E. inermis from Greece is reproduced in Figure 5 to show that, unlike that of E. marzouqui , it broadens towards the apex which is triangular.

Etymology. This species is named for Fawaz Al-Marzouq who created the Sabah Al-Ahmad Sea City in whose waterways E. marzouqui was discovered.

Figures

FIGURE 1. Map of the Arabian region showing collection locations for Eurydice species.

FIGURE 4. Eurydice marisrubri sp. nov. Holotype (SMF 34845): a, b, paratypes (SMF 34846) Ƥ: c – m. a lateral b, dorsal view; c, antennule; d, antennal peduncle; e tip of antenna; f mandible; g, maxillule; h, maxilla; i, maxilliped palp; j, pereopod 1; k, pereopod 2; l, pereopod 3; m, pereopod 7. Horizontal scale = 1.0 mm, vertical scale = 0.1 mm.

FIGURE 5. Eurydice marzouqui sp. nov. 3 paratype (SMF 34841): a, pleopod l; b, pleopod 2 with appendix masculina; c, uropod. Eurydice tridentata sp. nov. paratype (SMF 34844): d, pleopod l; e, pleopod 2 with appendix masculina; f, uropod. Eurydice marisrubri (SMF 34846): g, pleopod 1; h, uropod; i, pleopod 2 with appendix masculina. Eurydice peraticis 4.0 mm 3 (SMF 39707): j, pleopod 2 with appendix masculina. Horizontal scale = 1.0 mm, vertical scale = 0.1 mm.