Coreoleuciscus aeruginos

Song, Ha-Yoon & Bang, In-Chul, 2015, Coreoleuciscus aeruginos (Teleostei: Cypriniformes: Cyprinidae), a new species from the Seomjin and Nakdong rivers, Korea, Zootaxa 3931 (1), pp. 140-150 : 141-146

Coreoleuciscus aeruginos

Fig. 1

Holotype. SUC 1290, male, 106.1 mm SL. Deokcheon River (a tributary of the Nakdong River). Geographic coordinates 35˚16′29.06″N, 127˚50′33.69″E. Cheonpyeong-ri, Sicheon-myeon, Sancheong-gun, Gyeongsangnamdo, Korea, Dec. 0 6, 2009, H. Y. Song.

Paratypes. SUC 1291-1309 (19), 1360-1382 (23), 2057-2075 (19), 2098-2123 (26), 2278-2301 (24) 2304- 2327 (24), 2328-2351 (24), 2397-2419 (23), 2442-2466 (25) 182 ex., 46.1–118.2 mm SL. Locality data in Table 1 .

Hwangji Stream (6) SUC7841 KF621055 Yeong River (7) SUC2304 KF621056 Miryang River (8) SUC2397 KF621057 Gyeongho River (9) SUC2442 KF621058 Deokcheon River (10) SUC1290 KF621059 Coreoleuciscus splendidus

Han River basin Imjin River (11) SUC1338 KF621035 Hantan River (12) SUC2420 KF621036 Jojong Stream (13) SUC1313 KF621037 Hongcheon River (14) SUC2231 KF621038 Pyeongchang River (15) SUC2124 KF621039 Hail Stream (16) SUC2489 KF621040 Seom River (17) SUC2163 KF621041 Diagnosis. Coreoleuciscus aeruginos is distinguished from C. splendidus using body coloration. C. splendidus has a golden line immediately above a luteous line that runs along a lateral line on side of body. C. aeruginos has a bluish-green line above the luteous line ( Fig. 2 ). During the spawning season, C. splendidus has a bright yellow line immediately above a violet and bluish line running along lateral line on side body, while C. aeruginos has a luteous line immediately above a black line ( Fig. 3 ).

The two species are futher distinguished by the shape and/or presence of black bands on dorsal, anal and caudal fin rays. Dorsal fin of C. splendidus with a thick and discontinuous distal band and a thick and continuous basal band (versus C. aeruginos with a thin and continuous band both distally and basally). C. splendidus has anal fin of quite thick and long distal dark band and short basal band (versus C. aeruginosa has anal fin of thin and relatively short distal band and no basal band). Between the two species, there are multiple notable differences in caudal fin. C. splendidus with a total of seven bands in centrosymmetric structure; three pairs of six thin bands separated into two lobes at medial and distal-most areas and a thin basal band extending outwards. In contrast, C.

aeruginos with three stripes in centrosymmetric structure; a thick and continuously band distally across lobes, one pair of two thick bands separated into two lobes medially, and a thick and short one at the basal part.

Description. Measurements and meristic data are provided in Table 2 . Body elongate, slender, and compressed. Body depth 19.0% (16.4–20.2%) SL. Predorsal length 49.9% (48.3–50.9) SL. Preanal length 75.0% (73.3–77.0%) SL. Length of caudal peduncle 20.3% (19.0–22.0%) SL. Body entirely covered by large cycloid scales. Head moderately compressed, length 25.2% (21.0–25.2%) SL; no maxillary barbels; snout elongate, length 36.4% (35.1–37.7%) HL; eye ovoid, orbital diameter 18.4% (18.2–20.8%) HL.

Lateral line scale rows 40–42; lateral line almost straight and complete, extending 1–2 scales to base of caudal fin; 4.5 scale rows above lateral line; and 3 scale rows below lateral line. Vertebrae 39–40 (inclusive of 4 for Weberian apparatus elements); gill rakers 7–8. All fins with distinct broad black stripes.

Dorsal fin rays iii, 7. There are two thin and continuous stripes at distal and basal portions of dorsal fin. Origin of dorsal fin is anterior to pelvic fin insertion. Pectoral fin with 13–14 rays. Pelvic fin rays ii, 7; fin with a single stripe consisting of black speckles on rays. Anal fin rays iii, 6; fin with a thin and relatively short stripe distally; basal band absent. Caudal fin with a total of three stripes forming a centrosymmetric structure; thick and short band at basal basally. Anal fin of adult shows sexual dimorphism; anal fin of males is always longer and wider than that of females. However, black stripes and bands on every fin ray does not exhibit sexual dimorphism in the two species Coreoleuciscus .

Coloration of live specimens. Live males. Head and body coloration light brown to black dorsally and grading to light silver ventrally to abdomen. The bluish-green line is above luteous line that runs along lateral line on the side of body. All fins colorless except for distinct black bands. Dorsal, anal, pelvic and caudal fins have black bands. Iris bright gold, pupil black ( Fig. 2 ).

Live females. Coloration is generally similar to that of males ( Fig. 2 ).

Coloration of fixed specimens. Head dark brown. Transverse black band extending from snout to operculum. Body dark brown above and yellowish below lateral line. Distal and basal dorsal fin with thin continuous black stripes; and no basal band on anal fin ( Fig. 1 ).

Sexual dimorphism. Anal fin of adult male always longer and wider than anal fin of adult female. During breeding season males possess nuptial tubercles on anal fins ( Fig. 4 ).

Description and habitat. Widely distributed in the Seomjin and Nakdong rivers of South Korea ( Fig. 4 ). Commonly inhabiting rapids of a stream ( Fig. 6 ).

Etymology. Species name “ aeruginos ” from Latin, referring to the bluish-green coloring, like verdigris. Common names. ‘Korean bluish shinner’ (English); ‘cham-swi-ri’ (Korean).

Figures

FIGURE 1. Coreoleuciscus aeruginos (holotype, SUC 1290, male, 106.1 mm SL, Nakdong River, Sancheong, Korea). Dorsal (A), lateral (B), and ventral (C) views.

FIGURE 2. Body coloration of fresh specimens of Coreoleuciscus aeruginos male (A) and female (B) from the Nakdong River and C. splendidus male (C) and female (D) from the Han River.

FIGURE 3. Nuptial coloration of fresh specimens of Coreoleuciscus aeruginos male (A) and female (B) from the Nakdong River and C. splendidus male (C) and female (D) from the Han River.

FIGURE 4. Schematic diagram showing black stripes on the dorsal, anal, and caudal fins in Coreoleuciscus aeruginos (A) and C. splendidus (B).

FIGURE 6. Typical habitat of Coreoleuciscus aeruginos in the Deokcheon River (a tributary of the Nakdong River), Sancheong, Korea.

Tables

TABLE 1. Samples, collection sites, and GenBank accession numbers for the Coreoleuciscus populations and outgroups used in the phylogenetic tree. The number in parenthesis behind the name of river or stream in locality indicates the sampling site in Figure 5.

Species	Locality (site number)	Voucher no. GenBank acc. no.
Coreoleuciscus aeruginos Seomjin River basin	Jowon Stream (1) Hwagae Stream (2)	SUC1360 KF621050 SUC2098 KF621051
Nakdong River basin	Gurim Stream (3) Samhwa Stream (4) (Namhae Island) Nakdong River (5)	SUC2328 KF621052 SUC2057 KF621053 SUC2278 KF621054

TABLE 2. Morphometric data for Coreoleuciscus aeruginos and C. splendidus.

Character	C. aeruginos	C. splendidus
Number of specimens Standard length (mm)	Holotype Paratypes SUC1290 SUC1291-1309 1 19 106.1 63.5–107.4(92.5±9.9)	SUC1313-1332 20 52.1–101.5(71.9±17.4)
Measurements on SL* (%)
Body depth Body width Depth of caudal peduncle	19.0 16.4–20.2(18.4±0.9) 13.0 9.8–13.0(11.7±0.6) 9.8 9.3–11.0(9.9±0.4)	15.8–19.4(17.2±0.9) 9.3–12.1(10.9±0.8) 8.9–10.3(9.7±0.3)
Length of caudal peduncle Predosal length	20.3 19.0–22.0(20.3±0.7) 49.9 48.3–50.9(49.3±0.7)	18.2–21.7(19.6±0.9) 49.0–51.1(49.7±0.7)
Preanal length Prepectoral length Prepelvic length Length of dorsal base	75.0 73.3–77.0(74.9±0.9) 22.7 21.0–23.5(22.5±0.7) 50.2 49.2–52.4(50.8±0.8) 12.2 10.1–12.4(11.1±0.6)	71.9–75.1(73.7±0.8) 22.4–25.6(23.8±0.9) 49.0–53.5(51.4±1.21) 9.1–12.3(11.1±1.0)
Length of anal base Head length Measurements on HL* (%) Head width	10.1 8.4–10.7(9.5±0.6) 25.2 21.0–25.2(23.7±0.9) 53.8 46.5–53.8(50.4±1.5)	7.4–10.7(8.8±1.0) 22.8–25.6(23.9±0.7) 46.3–49.9(48.2±0.8)
Snout length Orbital diameter Counts	36.4 35.1–37.7(36.4±0.7) 18.4 18.2–20.8(19.7±0.7)	34.2–36.5(35.3±0.68) 20.2–25.0(22.0±1.1)
Dorsal fin rays Anal fin rays Pelvic fin rays	iii 7 iii 7 iii 6 iii 6 ii 7 ii 7	iii 7 iii 6 ii 7
Later line scales Scales above lateral line Scales below lateral line	40 40–42 4½ 4½ 3 3	40–42 4½ 3
Vertebrae Gill raker	39 39–40 7 7–8	39–40 7–8