Protohyale (Boreohyale) kajiharai ( 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 : 239-243

Protohyale (Boreohyale) kajiharai ( Hiwatari, 2003)

(Korean Name: O-mok-son-hae-jo-sum-i-yeop-sae-u, new) ( Figs 5–7 )

Hyale kajiharai Hiwatari, 2003: 235 , figs 4–6.

Material examined. 3 Ƌ 3 ♀, Gangneung-si, Gangwon-do, 29 April 1999, (Y. Eun); 20 Ƌ, Taejongdae, Busan-si, 5 June 2001, (Y. Eun); 3 Ƌ, Jeodong-ri, Ulreungdo Is., 20 October 2001, (Y. Eun); 26 Ƌ 30 ♀, Bongpyeong-ri, Uljingun, 10 July 2002, (Y.H. Kim); 1 Ƌ, Udo-myeon, Jejudo Is., 9 August 2005, (K.S. Lee); 5 Ƌ 11 ♀, Gyeongnyeolbiyeoldo-Is., Taean-gun, 9 May 2006, (Y.H. Kim); 12 Ƌ, Namae-ri, Yangyang-gun, 18 December 2007, (Y.H. Kim); 3 Ƌ 1 ♀, Daejin-ri, Goseong-gun, 22 October 2008, (Y.H. Kim); 4 Ƌ, Hamdeok-ri, Jejudo Is., 28 March 2013, (E.J. Kim, S. Lee & S.K. Lee,); 1 Ƌ 18 ♀, Geomundo Is., Yeosu-si, 25 April 2013, (Y. Eun); 11 Ƌ, Dongo-ri, Wando Is., 5 September 2013, (Y. Eun, S. Lee).

Type locality. Sokodo , Hachijo Is., Japan.

Description. Male. Body ( Fig. 5 A) about 5.5 mm long, dorsally smooth.

Head. Head subquadrate, as wide as long, shorter than pereonites 1–2 combined; eye medium, subround. Antenna 1 ( Fig. 5 B) shorter than 0.5 x antenna 2, length ratio of peduncular articles 1–3 = 1.00: 0.77: 0.66, peduncle slightly longer than half of flagellum, each article with short setae distally; flagellum 11-articulate, 2–8 articles bearing 1 or 2 short aesthetascs posterodistally. Antenna 2 ( Fig. 5 C) less than half of body length; flagellum 23-articulate, about 1.4 x peduncles. Left mandible ( Fig. 5 D) incisor 6-dentate; lacinia mobilis 5-dentate; molar with 1 pappose seta; 3 plumose setae placed between lacinia mobilis and molar process. Maxilla 1 ( Fig. 5 E) inner plate slender, apical margin with 2 plumose setae; outer plate stout, apical margin with 7 serrate spine-teeth; palp uniarticulate, with simple seta apically. Maxilliped ( Fig. 5 F) inner plate slightly shorter than outer plate, with 3 conical teeth apically, outer and apical margins with several setae; outer plate subovate, extending beyond half of palp article 2, with row of simple setae medially, slender setiform teeth and simple setae subapically; palp slender, 4-articulate, article 2 with simple setae on inner margin; article 3 apical margins with numerous long setae; article 4 elongate and strong, falcate, inner margin with short setae; unguis slender, acute.

Pereon. Gnathopod 1 ( Fig. 6 A) coxa trapezoidal, roundly produced anteroventrally; basis broadening distally, anterodistal margin with 1 seta and spine; carpus subtriangular, lobe narrowing posteriorly, lacking serration; propodus subovate, expanded posteriorly, length 1.4 x width, palm slightly convex, palmar corner with a strong spine; dactylus elongate, extending beyond palmar corner. Gnathopod 2 ( Fig. 6 B) coxa subquadrate; basis with hydrodynamic lobe anterodistally, anterior margin with 2 setae; ischium with large hydrodynamic lobe; carpus short, lacking lobe; propodus elliptical, narrowing distally, width 0.55 x length, palm gently convex, much longer than posterior margin, bearing truncate process near dactylus hinge, with a row of spines and setules; dactylus elongate, 0.7 x propodus. Pereopod 3 ( Fig. 6 C) coxa subquadrate, slightly longer than coxa 2; basis posterior margin with 3 setae; merus anterior margin with 3 spines; propodus rectangular, length 4.1 x width, posterior margin with 1-1-1-1-2 spine formula; dactylus large; length ratio of articles 2–7 = 1.00: 0.27: 0.58: 0.44: 0.74: 0.38. Pereopod 4 ( Fig. 6 D) similar to pereopod 3, but coxa broader. Pereopod 5 ( Fig. 6 E) slightly shorter than pereopod 4; coxa bilobate, much broader than long, anterior lobe slightly larger than posterior lobe; basis subovate, expanded posteriorly, posterior margin with slight notch at midpoint, anteroproximal margin with 1-1-1-2-2 spine formula; merus broadening distally, both margins with spines; carpus, posterior margin lacking spines; propodus rectangular, anterior margin with 1-2-1-2 spine formula; dactylus large, falcate; length ratio of articles 2–7 = 1.00: 0.33: 0.60: 0.55: 0.99: 0.55. Pereopod 6 ( Fig. 6 F) longer than pereopod 5; coxa shallow, bilobate, anterior lobe small, 0.53 x width of posterior lobe; basis subrectangular, angles softly rounded, length 1.32 x width, posterior margin with notch mid-proximally, anterior margin with 1-2-2-2-2 spine formula; length ratio of articles 2–7 = 1.00: 0.27: 0.75: 0.67: 1.00: 0.51. Pereopod 7 ( Fig. 6 G) coxa small, nonlobate, rounded ventrally; basis broad, subovate, anterior margin with row of spines, posterior margin strongly broadened, slightly serrate; length ratio of articles 2–7 = 1.00: 0.29: 0.77: 0.64:0.99: 0.58.

Pleon. Uropod 1 ( Fig. 7 A) peduncle slightly longer than rami, with 3 dorsomedial, 4 dorsolateral and 1 large distolateral spine, which is 0.32 x outer ramus; inner ramus with 3 dorsomedial and 2 apical spines; outer ramus with 2 dorsal and 5 apical spines. Uropod 2 ( Fig. 7 B) 0.63 x uropod 1; peduncle as long as outer ramus, with 1 dorsomedial and 2 dorsolateral spines; inner ramus 1.24 x outer ramus, with 2 dorsal and 5 apical spines; outer ramus with 2 dorsomedial and 3 apical spines. Uropod 3 ( Fig. 7 C) short, uniramous; peduncle longer than ramus, with 2 dorsal spines; ramus with 6 apical spines. Telson ( Fig. 7 D) fully bilobate, length 1.6 x width, each lobe with 2 penicillate setae dorsolaterally.

Female. Body about 6.2 mm long.

Pereon. Gnathopod 1 ( Fig. 7 E) coxa trapezoidal, longer than that of male; propodus subrectangular. Gnathopod 2 ( Fig. 7 F) coxa similar in shape but longer than that of male; basis-propodus similar to those of gnathopod 1; brood plate subtriangular, very large, apex round, longer than basis, with numerous long, hook-tipped setae marginally. Pereonite 2, preamplexing notch ( Fig. 7 G) strongly incised; unguisial groove broad, straight, oblique; posterodistal lobe shallow, sharply rounded anteriorly.

Remarks. Protohyale (Boreohyale) kajiharai has an elliptical shaped male gnathopod 2, so is easily distinguished from the other species. The following minor morphological differences were found between our specimens and the original description given by Hiwatari (2003) (characters of original description in brackets): 1) gnathopod 2, palm with strong spine (vs. striated peg spine); 2) telson, each lobe with 2 penicillate setae (vs. 3 setae). This species is widespread along the Korean coast, mainly amongst algae.

Distribution. Korea, Japan.

Figures

FIGURE 5. Protohyale (B.) kajiharai (Hiwatari, 2003), male, 5.5 mm, Gyeongnyeolbiyeoldo-Is., Taean-gun, Korea: A, lateral view; B, antenna 1; C, antenna 2; D, left mandible; E, maxilla 1; F, maxilliped. Scale bars = 1 mm (A – C), 0.2 mm (D – F).

FIGURE 6. Protohyale (B.) kajiharai (Hiwatari, 2003), male, 5.5 mm, Gyeongnyeolbiyeoldo-Is., Taean-gun, 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 7. Protohyale (B.) kajiharai (Hiwatari, 2003), male, 5.5 mm, Gyeongnyeolbiyeoldo-Is., Taean-gun, Korea: A, uropod 1; B, uropod 2; C, uropod 3; D, telson; female, 6.2 mm, Gyeongnyeolbiyeoldo-Is., Taean-gun, Korea: E, gnathopod 1; F, gnathopod 2; G, pereonite 2, preamplexing notch. Scale bars = 0.3 mm (A – F), 0.5 mm (G).