Protohyale (Boreohyale) magnaocularis, Eun, Ye, Hendrycks, Ed A. & Kim, Young-Hyo, 2016

Eun, Ye, Hendrycks, Ed A. & Kim, Young-Hyo, 2016, The family Hyalidae (Crustacea: Amphipoda: Talitroidea) from Korean waters. 2. Genus Protohyale Bousfield & Hendrycks, 2002, Zootaxa 4175 (3), pp. 231-248 : 235-239

Protohyale (Boreohyale) magnaocularis sp. nov.

(Korean Name: keun-nun-hae-jo-sum-i-yeop-sae-u, new) ( Figs 2–4 )

Type material. Holotype. Adult male, 12.5 mm, (NIBRIV0000556971), Beomseom Is., Seoguipo-si, Korea (33°13’01”N, 126°31’06”E), 3 September 2008, (Y. Eun) . Paratypes, 1 Ƌ, 1 ♀ (NIBRIV0000556972) other data same as holotype ; 4 ♂ 3 ♀ (NIBRIV0000556973) and 1 Ƌ 1 ♀ ( CMNC 2016-0108 ), Chujado Is., Bukjeju-gun , Korea (33°58’01”N, 126°16’55”E), 15 November 2008.

Etymology. The species name is derived from the Latin magna (=large) and ocularis (=eye) with reference to the large eyes.

Diagnosis. Body large, smooth; eyes very large, round; antenna 1 about 0.6 x antenna 2; gnathopod 1, propodus rectangular in form; gnathopod 2, propodus subovate in form, dactylus elongate, fitting palm; pereopod 6, basis subovate, as long as broad; uropod 3, ramus slender, short, about 0.5 x peduncle; telson, length 2 x width.

Description. Holotype, adult male.

Body ( Fig. 2 A) large, about 12.5 mm long, dorsally smooth.

Head. Head about 0.8 x length of pereonites 1–2 combined, half concealed by coxa 1; eye round, remarkably large, occupying more than half of the head. Antenna 1 ( Fig. 2 B) about 0.6 x antenna 2, length ratio of peduncular articles 1–3 = 1.00: 0.66: 0.44; flagellum 20-articulate, each article bearing 2 or 4 long aesthetascs and short setae distally. Antenna 2 ( Fig. 2 C) long, 0.5 x body length, peduncular articles 2–5 bearing short setae distally, flagellum long, 42-articulate, articles 1–16 with setal brushes ventrally. Upper lip ( Fig. 2 D) covered with patch of pubescence apically. Lower lip ( Fig. 2 E) inner lobes indistinct; outer lobes densely pubescent. Left mandible ( Fig. 2 F) incisor 8-dentate; lacinia mobilis 6-dentate; molar strongly triturative, with 1 pappose seta; 3 accessory stout plumose setae between lacinia mobilis and molar. Maxilla 1 ( Fig. 2 G) inner plate slender, subrectangular, with 2 plumose setae apically; outer plate stout, apical margin with 7 serrate spine-teeth; palp uniarticulate, pubescent, reaching distal end of outer plate, with 1 apical seta. Maxilla 2 ( Fig. 2 H) inner plate densely setose apically, with 1 pectinate seta midmedially; outer plate slightly shorter than inner one. Maxilliped ( Fig. 2 I) inner plate slightly shorter than outer plate, with plumose setae medially and 3 conical teeth apically; outer plate subovate, extending to nearly half of palp article 2, with row of medial and apical simple setae; palp elongate, 4-articulate, article 2 broad, with pinnate setae on inner margin; article 3 subrectangular, densely setose apically; article 4 elongate, falcate, unguis slender, acute, with a short apical spine.

Pereon. Gnathopod 1 (Fig. 3A) coxa broadening distally, roundly produced anteroventrally, lacking posterior marginal cusp; basis broadening distally, with 2 marginal short setae midposteriorly; carpus, subtriangular, short, 0.64 x propodus, lobe rounded, with ventral setae; propodus subrectangular, narrow, length 2.5 x width, palm slightly oblique, defined by 2 spines; dactylus shorter than half of propodus, extending beyond palm. Gnathopod 2 (Fig. 3B) coxa subquadrate, smaller than coxa 1; basis and ischium with large hydrodynamic lobes anterodistally; carpus short, lacking lobe; propodus massive, subovate, width 0.62 x length, anterior margin with 4 proximal spines; palm slightly convex, subequal to ventral margin, with rows of long spines; dactylus falcate, fitting palm. Pereopod 3 (Fig. 3C) slender, coxa similar to coxa 2; basis, posterior margin with row of setae; merus anterior margin with 3 spines; propodus length 5 x width, posterior margin with 1-1-1-1-1-1 spine formula; dactylus long, slightly shorter than half of propodus, with weak distal seta; length ratio of articles 2–7 = 1.00: 0.30: 0.55: 0.44: 0.90: 0.40. Pereopod 4 (Fig. 3D) similar to pereopod 3, except coxa broader. Pereopod 5 (Fig. 3E) as long as pereopod 4; coxa bilobate, much broader than long, anterior lobe subequal in width to posterior lobe; basis broadly expanded, posterior margin crenulate, with slight notch at midpoint, anterior margin with 1-1-1-1-1-2-1-2 spine formula; merus broadening distally, both margins with spines; carpus, posterior margin lacking spines; propodus rectangular, anterior margin with row of 4 spines; dactylus elongate; length ratio of articles 2–7 = 1.00: 0.28: 0.68: 0.48: 0.91: 0.71. Pereopod 6 (Fig. 3F) longer than pereopod 5; coxa shallow, bilobate, anterior lobe small, about 0.4 x width of posterior lobe; basis subovate, as long as broad, posterodistal corner weakly angulated, anterior margin with 2-2-2-2-2 spine formula; merus-propodus longer than those of pereopod 5; dactylus similar to that of pereopod 5; length ratio of articles 2–7 = 1.00: 0.30: 0.60: 0.50: 0.82: 0.62. Pereopod 7 (Fig. 3G) coxa smaller than coxa 6; basis subquadrate, broad, width slightly exceeding length, anterior margin with 2-2-2-2-2 spine formula; posteroproximal corner weakly angulated, half of posterior margin crenulate; merus-dactylus longer than those of pereopod 6; length ratio of articles 2–7 = 1.00: 0.29: 0.73: 0.55: 1.00: 0.67.

Pleon. Uropod 1 ( Fig. 4 A) peduncle length subequal to outer ramus, with 3 strong dorsomedial, 4 dorsolateral and 1 distolateral large spine, which is 0.42 x outer ramus; inner ramus 1.16 x outer ramus, with 4 dorsomedial and 3 apical spines; outer ramus with 4 dorsal, 1 subapical and 2 apical spines. Uropod 2 ( Fig. 4 B) about 0.7 x uropod 1; peduncle 0.85 x outer ramus, with 2 dorsolateral and 1 dorsomedial spines; inner ramus about 1.2 x outer ramus, with 4 strong dorsomedial and 5 apical spines; outer ramus with 4 dorsal and 3 apical spines. Uropod 3 ( Fig. 4 C) short, uniramous, 0.32 x uropod 1; peduncle subrectangular, about 2.3 x ramus, with 2 dorsodistal spines; ramus small, slender, with 5 short apical spines. Telson ( Fig. 4 D) bilobate, relatively long, length 2 x width, each lobe with two pairs of penicillate setae dorsolaterally.

Female, paratypes. Body small, about 8.8 mm long.

Pereon. Gnathopod 1 ( Fig. 4 E) coxa similar to that of male, but slightly longer and not as broadened distally; basis slightly narrower; propodus slender, length 2.5 x width. Gnathopod 2 ( Fig. 4 F) coxa subequal to coxa 1; basis–merus similar to those of gnathopod 1; carpal lobe well developed; propodus slender; brood plate large, subtriangular, apex narrowed, length 2.0 x width; with long and hooked brood setae marginally. Pereonite 2, preamplexing notch ( Fig. 4 G) medium, sharply incised; unguisial groove narrow, very short, straight; pereonal posterodistal lobe broad, evenly rounded anteriorly.

Remarks. Protohyale (Boreohyale) magnaocularis is distinguished from P. (B.) misakiensis (characters of P. (B.) misakiensis in brackets) by the following features: 1) eyes large, more than 0.5 x width of head (vs. small, 0.3 x); 2) antenna 1 long, more than 0.6 x antenna 2 (vs. short, less than 0.5 x); 3) maxilliped, article 3 slender (vs. broad); 4) gnathopod 2, dactylus reaches the end of palm (vs. short, not reaching); 5) uropod 3, ramus slender, length 2.3 x width (vs. stout, 1.4 x) and 6) telson long, length 2 x width (vs. 1.5 x).

Distribution. Korea (Chujado Is., Jejudo Is.).

Figures

FIGURE 2. Protohyale (B.) magnaocularis sp. nov., holotype, male, 12.5 mm, Beomseom Is., Seoguipo-si, Korea: A, lateral view; B, antenna 1; C, antenna 2; D, upper lip; E, lower lip; F, left mandible; G, maxilla 1; H, maxilla 2; I, maxilliped. Scale bars = 1 mm (A – C), 0.3 mm (D – I).

FIGURE 4. Protohyale (B.) magnaocularis sp. nov., holotype, male, 12.5 mm, Beomseom Is., Seoguipo-si, Korea: A, uropod 1; B, uropod 2; C, uropod 3; D, telson; paratype, female, 8.8 mm, Beomseom Is., Seoguipo-si, Korea: E, gnathopod 1; F, gnathopod 2; G, pereonite 2, preamplexing notch. Scale bars = 0.5 mm (A – C, G), 0.3 mm (D – F).