Protohyale (Boreohyale) latimana ( Hiwatari, 2003 )

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 : 243-246

Protohyale (Boreohyale) latimana ( Hiwatari, 2003)

(Korean Name: Hok-deung-son-hae-jo-sum-i-yeop-sae-u, new) ( Figs 8–10 )

Hyale latimana Hiwatari, 2003: 253 , figs 14–15.

Material examined. 1 Ƌ 1 ♀, Marado Is., Seoguipo-si, 6 May 1994, (B.J. Kang).

Type locality. Matsugaura , Kagoshima, Japan.

Description. Male. Body ( Fig. 8 A) about 7.6 mm long, dorsally smooth.

Head. Head subquadrate, as long as pereonite 1; eye medium, circular. Antenna 1 ( Fig. 8 B) slightly longer than half of antenna 2, length ratio of peduncular articles 1–3 = 1.00: 0.89: 0.89, peduncle about 0.3 x flagellum, each article with short setae distally; flagellum 18-articulate, each article bearing 2 short aesthetascs. Antenna 2 ( Fig. 8 C) slightly longer than half of body length; peduncle about 0.3 x flagellum; flagellum long, 37-articulate. Upper lip ( Fig. 8 D) covered with patch of pubescence apically. Lower lip ( Fig. 8 E) inner lobes indistinct; outer lobes densely pubescent. Left mandible ( Fig. 8 F) incisor 8-dentate; lacinia mobilis 6-dentate; molar strongly triturative, with 1 long pappose seta; 3 plumose setae and pubescence placed between lacinia mobilis and molar process. Right mandible ( Fig. 8 G) incisor 8-dentate; lacinia mobilis with 2 serrate and 4 teeth; molar strongly triturative; 2 plumose setae placed between lacinia mobilis and molar process. Maxilla 1 ( Fig. 8 H) inner plate slender, apical margin with 2 plumose setae; outer plate stout, apical margin with 8 serrate spine-teeth; palp uniarticulate, with 1 apical plumose seta. Maxilla 2 ( Fig. 8 I) inner plate subequal to outer one, with 1 pectinate seta medially and numerous plumose setae apically; outer plate with numerous apical setae. Maxilliped ( Fig. 8 J) inner plate slightly extending beyond half of outer plate, with plumose setae medially and 3 conical teeth apically; outer plate subovate, extending beyond half of palp article 2, with row of simple setae medially, slender setiform teeth and simple setae apically; palp slender, 4-articulate, article 2 with simple setae on inner margin; article 3 inner and apical margins with numerous long setae; article 4 elongate, falcate, inner margin with short setae; unguis slender, acute.

Pereon. Gnathopod 1 ( Fig. 9 A) coxa trapezoidal, strongly widening distally, narrowly produced anteroventrally, ventral margin with weak notch; basis stout, broadening distally, posterior margin with 2 setae; carpal lobe narrowing posteriorly with cluster of setae; propodus expanded distally, anterodistal margin with hump, palm convex and defined by large, blunt cusp and two large spines; dactylus falcate, strongly curved, shorter than half of propodus. Gnathopod 2 ( Fig. 9 B) coxa subquadrate, anterodistal margin with hump; basis subrectangular, with hydrodynamic lobe anterodistally; ischium with large hydrodynamic lobe anteriorly; carpus short, with vestigial carpal lobe; propodus elliptical, narrowing distally, palm long and convex, with rows of long setae, defined by two spines; dactylus falcate, 0.71 x propodus, fitting palm. Pereopod 3 ( Fig. 9 C) slender, coxa similar to coxa 2; basis elongate, posterior margin with row of setae; propodus rectangular, posterior margin with 1-1-1-2 spine formula; dactylus falcate, elongate; length ratio of articles 2–7 = 1.00: 0.24: 0.54: 0.37: 0.72: 0.36. Pereopod 4 ( Fig. 9 D) similar to pereopod 3, except, coxa wider and produced posteriorly. Pereopod 5 ( Fig. 9 E) as long as pereopod 4; coxa bilobate, much broader than long, anterior lobe slightly larger than posterior lobe; basis subovate, posterior margin with weak notch, anterior margin with 6 spines; merus broadening distally, both margins with spines; carpus, posterior margin lacking spines; propodus rectangular, anterior margin with 1-1-1-2 spine formula; dactylus falcate, elongate; length ratio of articles 2–7 = 1.00: 0.32: 0.75: 0.50: 0.95: 0.48. Pereopod 6 ( Fig. 9 F) longer than pereopod 5; coxa shallow, bilobate, anterior lobe small, about 0.5 x width of posterior lobe; basis subovate, posterior margin with weak notch, posterodistal margin extended ventrally, anterior margin with row of spines; dactylus similar to that of pereopod 5; length ratio of articles 2–7 = 1.00: 0.27: 0.83: 0.58: 0.90: 0.51. Pereopod 7 ( Fig. 9 G) coxa small, rounded ventrally; basis subovate, extended posteriorly, posterior margin slightly serrate, with notch, anterior margin with row of spines; merus-dactylus similar to those of pereopod 6; length ratio of articles 2–7 = 1.00: 0.28: 0.85: 0.57: 1.00: 0.53.

Pleon. Uropod 1 ( Fig. 10 A) peduncle slightly shorter than rami, with 2 dorsomedial, 3 dorsolateral and 1 long distolateral spine, which is 0.46 x outer ramus; inner ramus with 4 dorsal and 5 apical spines; outer ramus with 2 dorsal and 4 apical spines. Uropod 2 ( Fig. 10 B) 0.72 x uropod 1; peduncle slightly shorter than outer ramus, with 2 dorsolateral and 1 dorsomedial spines; inner ramus 1.4 x outer ramus, with 2 dorsal and 4 apical spines; outer ramus with 3 dorsal and 4 apical spines. Uropod 3 ( Fig. 10 C) short, uniramous, about 0.4 x uropod 1; peduncle longer than ramus, with 3 dorsal spines; ramus with 7 apical spines. Telson ( Fig. 10 D) fully bilobate, length 1.6 x width, each lobe with 2 pairs of penicillate setae dorsolaterally.

Female. Body about 8.3 mm long.

Pereon. Gnathopod 1 ( Fig. 10 E) coxa trapezoidal, with ventral notch; basis and ischium with hydrodynamic lobes; carpal lobe well developed; propodus rounded posteriorly, slightly expanded, palm slightly oblique, defined by 2 spines. Gnathopod 2 ( Fig. 10 F) coxa similar in shape but longer than that of male; basis-propodus similar to those of gnathopod 1; brood plate subtriangular, very large, length 2.6 x width, apex round, longer than basis, with numerous long hook-tipped setae marginally. Preamplexing notch was very difficult to observe, so it is possible that it is very weakly developed.

Remarks. Our Korean specimens agree closely with the Japanese material in the original description by Hiwatari (2003). However, the following minor morphological differences were found between our material and the original description: 1) gnathopod 1, palm with 2 spines (vs. 1 spine); 2) uropod 2, outer ramus with 2 spines (vs. 3 spines); and 3) uropod 3, peduncular margin with 3 spines (vs. 4 spines).

Distribution. Korea, Japan.

Figures

FIGURE 8. Protohyale (B.) latimana (Hiwatari, 2003), male, 7.6 mm, Marado Is., Seoguipo-si., Korea: A, lateral view; B, antenna 1; C, antenna 2; D, upper lip; E, lower lip; F, left mandible; G, right mandible; H, maxilla 1; I, maxilla 2; J, maxilliped. Scale bars = 1 mm (A), 0.5 mm (B – C), 0.3 mm (D – J).

FIGURE 9. Protohyale (B.) latimana (Hiwatari, 2003), male, 7.6 mm, Marado Is., Seoguipo-si., Korea: A, gnathopod 1; B, gnathopod 2; C, pereopod 3; D, pereopod 4; E, pereopod 5; F, pereopod 6; G, pereopod 7. Scale bars = 1 mm (A – G).

FIGURE 10. Protohyale (B.) latimana (Hiwatari, 2003), male, 7.6 mm, Marado Is., Seoguipo-si., Korea: A, uropod 1; B, uropod 2; C, uropod 3; D, telson; female, 8.3 mm, Marado Is., Seoguipo-si., Korea: E, gnathopod 1; F, gnathopod 2. Scale bars = 0.6 mm (A – D), 0.5 mm (E – F).