Sinoediceros hwanghaensis, Kim & Hendrycks & Lee, 2012

Kim, Young-Hyo, Hendrycks, Ed A. & Lee, Kyung-Sook, 2012, New genera and species of the Synchelidium group (Amphipoda: Oedicerotidae) from Asia-North Pacific, Journal of Natural History 46 (37 - 38), pp. 2349-2376 : 2370-2375

Sinoediceros hwanghaensis sp. nov.

(Korean name: Hwang-hae-but-eun-nun-yeop-sae-u, new)

( Figures 10–12 )

Type material

Holotype. Adult female. Body 4.5 mm (appendages on one slide), NIBRIV0000246432, Namdong-ri Jindo Island, Korea (34 ◦ 21 ′ 44 ′′ N, 126 ◦ 09 ′ 01 ′′ E), 29 June 2004, sieved mud, collected by Y.-H. Kim.

Paratypes. Three females, 3.1–5.0 mm, CMNC 2012-0014 , other data same as holotype ; 30 females, 2.5–4.2 mm, DKU 201206 , other data same as holotype .

Additional material examined. One female, Boleumdo Island, Korea (37 ◦ 39 ′ 47 ′′ N, 126 ◦ 12 ′ 38 ′′ E), 26 April 2001, sieved mud; 10 females, Narodo beach, Oenalodo Island, Korea (34 ◦ 28 ′ 07 ′′ N, 127 ◦ 28 ′ 16 ′′ E), 31 July 2001, sieved mud ; 19 females, Dochodo Island , Korea (34 ◦ 39 ′ 42 ′′ N, 125 ◦ 56 ′ 51 ′′ E), 14 September 2002, sieved mud; one female, Jungwang-ri, Seosan-si, Korea (36 ◦ 53 ′ 12 ′′ N, 126 ◦ 22 ′ 49 ′′ E), 25 September 2002, sieved mud ; 19 females, Daewhang-ri , Seosan-si, Korea (36 ◦ 50 ′ 14 ′′ N, 126 ◦ 21 ′ 27 ′′ E), 25 September 2002, sieved mud ; 34 females, Bongjeon-ri Yeosu-si , Korea (34 ◦ 48 ′ 41 ′′ N, 127 ◦ 31 ′ 25 ′′ E), 21 March 2004, sieved mud. All material collected by Y.-H. Kim.

Etymology

The new species is named after the main collecting location. The Korean name for the Yellow Sea is Hwanghae.

Description

Holotype female. Body ( Figure 10A ) 4.5 mm long, head as long as pereonites 1–3 combined, narrowing anteriorly; rostrum subacute apically, reaching about 0.3 times peduncular article 1 of antenna 1; lateral cephalic lobe acute; trace of ommatidia not observed.

Antenna 1 ( Figure 10B ) subequal in length to head and pereonites 1–2 combined; length ratio of peduncular articles 1–3 = 1.00: 0.43: 0.24; peduncular article 1 stout, with 9–11 tiny plumose setae on surface and four or five penicillate setae marginally; peduncular article 3 short, 0.71 times flagellum article 1; flagellum six-articulate, setose, slightly shorter than peduncle.

Antenna 2 ( Figure 10C ) slightly longer than antenna 1; gland cone of peduncular article 2 well developed, nearly reaching end of peduncular article 3; peduncular articles 3–5 setose laterally and ventrally, length ratio = 1.00: 1.36: 1.22; flagellum reduced, very short, 0.26 times peduncles, four-articulate, flagellum article 1 subequal to following articles combined.

Lower lip ( Figure 10D ) inner lobe rounded, coalescent; outer lobe pubescent apically, armed with two pairs of small gland cones on inner margin.

Left mandible ( Figure 10E ) incisor smooth, with small teeth on both sides; lacinia mobilis broad, appearing five-dentate; accessory spine row with four spines; molar small, with two spines (bifid and serrulate), positioned far away from end of spine row; palp triarticulate, length ratio = 1.00: 1.73: 1.60, second article with eight A2 and D2 simple setae, distal article with three D3 setae and two long E3 setae.

Right mandible ( Figure 10F ) similar to left one, but lacinia mobilis absent, accessory spine row with five spines.

Maxilla 1 ( Figure 10G ) inner plate ovate, with one apical seta; outer plate with seven spine-teeth (bifid, trifid and denticulate) apically; palp biarticulate, distal article 3.20 times proximal one, with 11 simple setae apically.

Maxilla 2 ( Figure 10H ) plates narrowing distally and bent inwards, inner plate slightly shorter than outer one, with five unequal simple setae apically.

Maxilliped ( Figure 10I ) inner plate small, with three apical setae; outer plate reaching 0.75 times palp article 2, medial and apical margins with 15 spines; palp four-articulate, length ratio = 1.00: 2.44: 1.38: 1.10; article 2 longest, setose medially.

Gnathopod 1 ( Figure 11A ) coxa subquadrate, with four setae ventrally, posteroventral margin with small cusp; basis rectangular, anterior margin with tiny setae, anterodistal and posterior margins each with four long simple setae; ventral margin of merus subequal in length to dorsal margin of carpus; carpus 0.44 times propodus, carpal lobe sword-like, robust, extending slightly beyond posterior end of propodus, with simple setae ventrally; propodus subrectangular, palm oblique, with row of feeble hooked setae, 0.66 times ventral margin, delimited by one spine; dactylus falcate, fitting palm.

Gnathopod 2 ( Figure 11B ) very similar to gnathopod 1 in form, but each article slightly longer and larger in proportion than gnathopod 1.

Pereopod 3 ( Figure 11C ) setose; coxa similar to coxa 1 but wider, ventral margin slightly concave with 10 simple setae, one tiny seta anteroventrally and cusp posteroventrally; basis robust, narrowed proximally, 1.35 times merus, with two groups of oblique setal rows on surface; merus strongly widened anterodistally, with strong setal row along broadened anterolateral margin, subequal in length to carpus and propodus combined; carpus strongly setose posteriorly; propodus with three stout setae and one simple seta posteriorly, and group of 11 simple setae distally; dactylus broad, elongate, longer than propodus, with penicillate seta proximally.

Pereopod 4 ( Figure 11D ) similar to pereopod 3, but coxa subsquare, margins of basis setose, anterior margin of merus slightly less broadened.

Pereopod 5 ( Figure 11E ) coxa wide, 1.66 times length, 1.57 times coxa 4, bilobate, midventral margin slightly concave; basis oval, anterior margin with 17 long setae, anteromedial and posteromedial surfaces with one and 13 plumose setae; merus expanded distally, both margins with nine simple setae, posterodistal corner with three plumose setae; carpus–propodus short, subequal to merus; dactylus short, 0.64 times propodus.

Pereopod 6 ( Figure 12A ) similar to pereopod 5, but coxa 6 much narrower, 0.63 times coxa 5; anterior margin of basis strongly convex, anteroproximal margin with eight simple setae, anterodistal margin with 16 long, plumose setae, anterolateral surface with eight simple setae, anterodistal corner with three simple setae, posteromedial margin fully setose; merus longer and narrower than that of pereopod 5; propodus 1.3 times carpus; dactylus short, 0.38 times propodus.

Pereopod 7 ( Figure 12B ) coxa small, subquadrate, narrowing posteriorly, ventral margin with tiny seta and six plumose setae; basis pyriform, gradually narrowed distally, anterior margin with five spines, posterior margin with four simple and 11 plumose setae, posterodistal margin with one spine; merus subequal in length to carpus, 0.82 times propodus, both with spinose margins; dactylus elongate, slightly shorter than propodus, margins with seven short setae and nine long simple setae, with long simple seta apically.

Epimeral plate 1 ( Figure 12C ) ventral margin straight, with two setae, posterodistal margin narrowly rounded; epimeral plate 2 slightly deeper than plates 1 and 3, broadly rounded ventrally, with six setae, posterodistal margin subquadrate; epimeral plate 3 medially broad, ventral margin rounded, with two setae, posterodistally truncate.

Pleopods strong, rami long, subequal, articles with long plumose setae.

Uropod 1 ( Figure 12D ) peduncle rectangular, 1.59 times outer ramus, dorsolateral margin with 13 spines, medial margin with 10 setae, proximolateral margin with one spine; outer ramus shorter than inner one, with two spines; inner ramus with six long, slender setae medially.

Uropod 2 ( Figure 12E ) peduncle 1.21 times outer ramus, with seven dorsolateral spines, medial margin with seven spine-like setae; outer ramus 0.82 times peduncle, with two dorsolateral spines; inner ramus with five slender setae medially.

Uropod 3 ( Figure 12F ) peduncle slightly shorter than rami, dorsomedial margin with two spines; inner ramus slightly shorter than outer one, with three slender setae medially; medial margin of outer ramus minutely serrate.

Telson ( Figure 12G ) length 1.21 times breadth, distal margin with a pair of setules, dorsolateral margins with a pair of unequal penicillate setae.

Male. Unknown.

Remarks

Before our study, Sinoediceros homopalmulus Shen, 1955 represented a monotypic genus that was reported from the coastal waters of the East China Sea. Sinoediceros hwanghaensis sp. nov. is differentiated from S. homopalmulus by the following characteristics ( S. homopalmulus characters in parentheses): 1) flagellum of antenna 2 very short, 0.25 times peduncle (vs. 0.45 times peduncle); 2) the carpal lobe of gnathopod 2 extending just beyond posterior end of propodus (vs. greatly exceeding posterior end of propodus); 3) rami of uropod 3 slightly longer than peduncle, about 1.1 times peduncle (vs. much longer than peduncle, about 1.5 times peduncle); 4) mandibular palp article 3 elongate, subequal to article 2 (short, 0.5 times article 2); and 5) outer plate of the maxilliped elongate, reaching 0.75 times palp article 2 (vs. short, reaching palp article 1).

Distribution

Korea (Yellow Sea, Korea Strait).

Key to the species of Sinoediceros

1. Antenna 2 flagellum long, about 0.45 times peduncles; carpal lobe of gnathopod 2 greatly exceeding propodus; rami of uropod 3 elongate, about 1.5 times peduncle; outer plate of maxilliped short, reaching palp article 1................................................ S. homopalmulus Shen, 1955 Antenna 2 flagellum very short, 0.25 times peduncles; carpal lobe of gnathopod 2 extending just beyond propodus; rami of uropod 3 about 1.1 times peduncle; outer plate of maxilliped elongate, greatly exceeding palp article 1.......................................... S. hwanghaensis sp. nov.

Figures

Figure 10. Sinoediceros hwanghaensis sp. nov., holotype, female, 4.5 mm: (A) habitus; (B) antenna 1; (C) antenna 2; (D) lower lip (from paratype, 4.3 mm); (E) left mandible; (F) right mandible; (G) maxilla 1; (H) maxilla 2; (I) maxilliped. Scale bars = 0.5 mm (A), 0.2 mm (B, C), 0.05 mm (D–I).

Figure 11. Sinoediceros hwanghaensis sp. nov., holotype, female, 4.5 mm: (A) gnathopod 1; (B) gnathopod 2; (C) pereopod 3; (D) pereopod 4; (E) pereopod 5. Scale bar = 0.2 mm.

Figure 12. Sinoediceros hwanghaensis sp. nov., holotype, female, 4.5 mm: (A) pereopod 6; (B) pereopod 7; (C) pleonites; (D) uropod 1; (E) uropod 2; (F) uropod 3; (G) telson. Scale bars = 0.4 mm (C), 0.2 mm (A, B, D–F), 0.1 mm (G).