Guernea ezoensis Ishimaru, 1987

Kim, Young-Hyo, Hendrycks, Ed A. & Lee, Kyung-Sook, 2011, The genus Guernea Chevreux, 1887 from Korean waters (Crustacea: Amphipoda: Dexaminidae), Zootaxa 3104, pp. 1-25 : 5-9

publication ID	https://doi.org/ 10.5281/zenodo.204467
DOI	https://doi.org/10.5281/zenodo.6191764
persistent identifier	https://treatment.plazi.org/id/1E0187EC-FFC9-FFE3-FF6D-F99FB13BCAD6
treatment provided by	Plazi
scientific name	Guernea ezoensis Ishimaru, 1987
status

Treatment

Guernea ezoensis Ishimaru, 1987 View in CoL

(Korean Name: Hot-ka-i-do-but-eun-kko-ri-yeop-sae-u, new) ( Figs. 2A View FIGURE 2. A , 3–5 View FIGURE 3 View FIGURE 4 View FIGURE 5 )

Guernea ezoensis Ishimaru, 1987 View in CoL , p. 1404, figs. 7–11.

Material examined. 8 3, 3 Ƥ, Seomang, Jindo Is., 23 July 1994, (B.J. Kang); 17 3, 1 Ƥ, Namchang, Haenam-gun, 20 May 1998; 2 Ƥ, Heungnam, Geojedo Is., 3 July 1998; 78 3, 9 Ƥ, Chubongdo Is., Tongyeong-si, 10 July 1998, (C.M. Lee); 1 3, Changsundo Is., Namhae-gun, 20 November 1999; 3 3, 1 Ƥ, Panpo-ri, Jejudo Is., 11 July 2001; 2 3, Imwon, Samcheok-si, 22 August 2001; 12 3, 5 Ƥ, Wolpyeong, Jindo Is., 29 June 2004; 1 3, Mohang, Buangun, 2 October 2004; 2 3, Inpyeong-dong, Tongyeong-si, 23 August 2005; 5 Ƥ, Seokbyeong-ri, Pohang-si, 26 August 2005; 13 3, 1 Ƥ, Okdo Is., Seosan-si, 24 August 2006; 54 3, 10 Ƥ, Gobongpo, Baengnyeongdo Is., 12 July 2006; 2 3, Yonggipo, Baengnyeongdo Is., 12 July 2006; 47 3, 7 Ƥ, Junghwa-ri, Baengnyeongdo Is., 13 July 2006; 4 specimens, Mongsanpo, Taean-gun, 23 August 2006; 50 specimens, Daeho, Dangjin-gun, 1 September 2006; 18 specimens, Sapgyo, Yesan-gun, 21 December 2006; 17 specimens, Gajin, Goseong-gun, 22 February 2007; 6 specimens, Bongpo, Goseong-gun, 23 February 2007; 11 specimens, Gobongpo, Baengnyeongdo Is., 13 July 2007 (S.S. Hong); 30 specimens, Yonggipo, Baengnyeongdo Is., 14 July 2007 (S.S. Hong); 3 specimens, Gajin, Goseong-gun, 3 August 2007; 30 specimens, Sacheon, Gangreung-si, 8 May 2008; 4 specimens, Anmok, Gangreungsi, 9 May 2008; 7 specimens, Bito-ri, Sacheon-si, 22 May 2008; 2 specimens, Dapo, Geojedo Is., 13 June, 2008; 4 specimens, Ganggu, Yeongdeok-gun, 20 June 2008; 10 specimens, Namhangjin, Gangreung-si, 10 July 2008 (H.H. Sang); 12 specimens, Gyeongpo, Gangreung-si, 11 July 2008 (S.S. Hong); 3 specimens, Unjin port, Jejudo Is., 4 September 2008; 20 specimens, Bangpo, Taean-gun, 2 April 2009 (S.S. Hong); 3 specimens, Seodo-ri, Geomundo Is., 16 April 2009.

Type locality. Oshoro, Hokkaido, Japan.

Description. Male. Body ( Figs. 2A View FIGURE 2. A , 3 View FIGURE 3 A) small, about 2.5 mm long, strongly chitinized; cephalon as wide as long, slightly longer than pereonites 1–2 combined; rostrum short and minute; eye comparatively large, subcircular, composed of numerous ommatidia, occupying much of the cephalon, vermillion color when alive, lateral cephalic lobe broadly rounded; pereonites subequal in length to pleonites; urosomite 1 ( Fig. 3 View FIGURE 3 B) slightly notched dorsomedially, dorsodistally with weak carination; urosomites 2–3 distally truncated, lateral margins raised into ridges, hollowed dorsally, ridges armed with 2 or 3 pairs of dorsal spines.

Antenna 1 ( Fig. 3 View FIGURE 3 C) peduncular article 1 stout, slightly convex ventromedially, half of ventrodistal margin with long setular tufts; length ratio of peduncular articles 1–3 = 1.00: 0.66: 0.26; accessory flagellum very small, uniarticulate, with 1 apical seta; flagellum 8-articulate, armed with aesthetascs ventrally.

Antenna 2 ( Fig. 3 View FIGURE 3 D) slightly shorter than twice length of antenna 1; peduncular articles 1–3 short, peduncular article 4 1.10 x as long as peduncular article 5, with numerous setular tufts dorsally; flagellum 14-articulate, subequal in length to peduncle.

Mandible ( Fig. 3 View FIGURE 3 E) incisor smooth, marginally bifid, with weak definitions; right lacinia mobilis bifurcate, proximal branch 3–4 dentate, distal branch with 2–3 blunt teeth; left lacinia mobilis 5-dentate; molar well developed.

Maxilla 1 ( Fig. 3 View FIGURE 3 F) inner plate much smaller than outer, without apical seta; outer plate with 7 tooth-like spines apically; palp biarticulate, apical article longer than proximal, with 1 subapical, 2 apical setae and slender acute tooth.

Maxilla 2 ( Fig. 3 View FIGURE 3 G) inner plate about 0.7 x as long as outer plate, with 3 apical and subapical setae; outer plate curved, with 1 seta laterally and 5 setae apically.

Gnathopod 1 ( Fig. 3 View FIGURE 3 H) coxa comparatively small, oblong, with 2 fine setules ventrally; basis narrowing and curved proximally, anteromedial margin with 2 short setae, posterior margin with 5 long setae, distally with 1 long seta; carpus triangular, about 0.8 x as long as propodus, with unipectinate stiff spines ventrally; propodus quadrate, with 3 unipectinate setae dorsally; palm nearly transverse, with fine unequal setules marginally, defined by 4 spines on palmar corner; dactylus falcate, slightly shorter than length of palm.

Gnathopod 2 ( Fig. 3 View FIGURE 3 I) coxa similar to coxa 1, narrowing distally, with 3 fine setules ventrally; basis linear, elongate, with 2 fine setae anterodistally, 5 long setae posteriorly, distally with 1 seta; carpus and propodus more slender than those of gnathopod 1; propodus about 1.1 x as long as carpus, palm defined by 3 spines on palmar corner; dactylus falcate, inner margin with 1 tooth.

Pereopod 3 ( Fig. 4 View FIGURE 4 A) coxa narrowly rounded, ventral margin with 4–5 setules; basis rectangular, about 1.6 x as long as merus; carpus about half as long as merus, with 4 strong spines ventrally; propodus more slender and about 1.2 x as long as carpus; dactylus short.

Pereopod 4 ( Fig. 4 View FIGURE 4 B) very similar to pereopod 3, but coxa 4 larger and wider; carpus with 3 strong spines ventrally.

Pereopod 5 ( Fig. 4 View FIGURE 4 C) coxa bilobate, posterodistal lobe round, large, broadly expanded ventrally; basis subovate, pear-shaped, narrowing proximally, 0.7 x as wide as long; ischium to dactylus thin, more slender than basis; merus about 1.2 x as long as carpus, with 5 anterior setae and 1 posterodistal spine; carpus about 1.1 x as long as propodus, posterior margin with 1–1–2 spine formula; propodus rectangular, with posterodistal spine; dactylus falcate, about half length of propodus.

Pereopod 6 ( Fig. 4 View FIGURE 4 D) coxa subovate, comparatively smaller than those of the other pereopods; basis ovate, slightly convex anteriorly, expanded posteriorly; ischium with 1 anterodistal pinnate setae; merus longer and broader than carpus, both margins with 5 pinnate setae; carpus slightly longer than propodus, posterior margin with 1–1–2 spine formula.

Pereopod 7 ( Fig. 4 View FIGURE 4 E) coxa subovate, slightly longer than wide; basis wide, anterior margin straight, very broadly expanded posteriorly, about 0.9 x as wide as long; merus and carpus setose, with pinnate setae and spines, merus broad, about 1.4 x as long as carpus, carpus and propodus subequal in length.

Uropod 1 ( Fig. 4 View FIGURE 4 F) peduncle slightly more than twice the length of outer ramus, with 2 dorsolateral spines; inner ramus slightly shorter than outer, both with strong apical spines.

Uropod 2 ( Fig. 4 View FIGURE 4 G) peduncle about 1.7 x as long as outer ramus; outer and inner rami subequal in length, both with strong apical spines.

Uropod 3 ( Fig. 4 View FIGURE 4 H) peduncle stout, slightly longer than outer ramus, with apicolateral robust spine; outer ramus slightly shorter than inner, with 5 plumose setae and 1 spine; inner ramus with 3 plumose setae and 1 or 2 spines.

Telson ( Fig. 4 View FIGURE 4 I) subtriangular, length about 1.3 x width, deeply cleft (85%), each lobe with 1 apical pinnate spine and row of dorsal cuticular pores.

Female. Body ( Fig. 5 View FIGURE 5 A) small, about 3.4 mm long. Similar to male, but body broader, eye much smaller, antennae 1–2 ( Figs. 5 View FIGURE 5 B–C) without setular tufts on peduncles; antenna 2 much shorter, pereonites broader than those of male; pereopod 5 ( Fig. 5 View FIGURE 5 D) basis broader, with row of pinnate setae on anterior margin; rami of uropod 3 ( Fig. 5 View FIGURE 5 E) without plumose setae; telson ( Fig. 5 View FIGURE 5 F) subtriangular, without row of cuticular pores dorsally.

Distribution. Japan (Hokkaido), Korea.

Remarks. Specimens examined generally conform to the original description of Ishimaru (1987), with some minor morphological differences. These differences include the number of flagellar articles of antenna 1, the spination on the peduncles and rami of uropods 1–3 and the armature of the telson. These morphological differences seem to be size related or local variation.