Sarcocheilichthys hanjiangensis Chen & Li, 2024

Chen, I-Shiung & Li, Hsien-En, 2024, A new rainbow gudgeon of Sarcocheilichthys (Teleostei: Cyprinidae) from Fujian Province, China with redescriptions of S. hainanensis, Zootaxa 5550 (1), pp. 258-270 : 262-268

Sarcocheilichthys hanjiangensis Chen & Li , new species

( Figs 2–6 )

Materials Examined

Holotype: NTOUP-2008-12-004 , 53.02 mm SL; Ting Jiang, tributary of Hanjiang, Changtin County, Longyan City, Fujian Province, PRC; coll. I-S. Chen et al., 4 December 2008 .

Paratypes: All paratypes were collected with the holotype. NTOUP-2008-12-005, 12 (44.85–57.94 mm SL) .

Diagnosis. The Hanjiang rainbow gudgeon, Sarcocheilichthys hanjiangensis , can be distinguished from its congeners by the following unique combination of characters (counts for holotype marked with an asterisk): (1) fin rays: D 3+7*; A 3+6*; P 1 1+14*; P 2 1+7*; (2) scales: LL 37*–39; TR 8*–9; PreD 10*; (3) vertebral count 4+33*; (4) body features: body relatively robust. Pharyngeal teeth in 2 rows. Lip lobes elongated, spindle-like with blunt anterior end; barbles absent. Male individuals with a finger-like protrusion posterior to anus; female ovipositor short, with a simple tube-like opening; and (5) coloration: body scattered with patches of black blotch; fins whitishorange; dorsal fin with a tadpole-like blotch.

Description. Body proportions as shown in Table 1 , frequencies of meristic counts in Table 2 . Counts for holotype marked with an asterisk. Body spindle-shaped, depth greatest at dorsal fin base, and slightly compressed laterally. Body profile slightly convex anterior to dorsal fin base and straight posterior towards posterior end of caudal peduncle dorsally and ventrally. Snout blunt. Mouth slightly oblique, inferiorly positioned; upper jaw prominent, posterior end of gape touches the anterior edge of orbit but not succeeding; both jaws retractable, outstretching downward. Upper lip thin; tip of lower lip with well-developed horny sheath. Pharyngeal teeth in two rows ( Fig. 3 ), longer teeth hook-like. Lower lip with two lateral lobes ( Fig. 4A ), elongated and narrow, situated along lower jaw, anterior end pointing towards tip of lower jaw, connecting to upper lip posteriorly. Barbles absent. Anus located in middle between pelvic fin insertion and anal fin origin. Male individuals with a short, finger-like extension just posterior to anus ( Fig. 7A ). Female individuals with ovipositor, length not extending to anal fin origin, ovipositor tube gradually reduced posteriorly until shaping like a bottleneck at posterior tip with a simple pore opening ( Fig. 7B ). Vertebrae 4+33.

Fins. Dorsal fin with 3 unbranched rays and 7 branched rays (13); anal fin with 3 unbranched rays and 6 branched rays (13); pectoral fins with 1 unbranched ray and 14 branched rays (13); pelvic fins with 1 unbranched ray and 7 branched rays (13). All fins flexible. Both dorsal fin and anal fin with exceptionally short first unbranched ray. Dorsal fin origin anterior to pelvic fin insertions, posterior end of fin base about vertical position of anus. Pectoral fins almost horizontal, almost same length as head, posterior tips not surpassing pelvic fin insertions. Posterior tip of pelvic fins extending beyond anus when compressed. Caudal fin forked, upper and lower lobes equal in length and shape, posterior tips rounded. All fins without elongated rays in both sexes.

Squamation. Lateral line pored scales 37* (4), 38 (7), or 39 (2); transverse scale rows 8* (9) or 9 (4); predorsal scales 9 (3) or 10* (10). All scales cycloid and in moderate size; no exceptionally enlarged scales. Head completely naked, predorsal regions scaled until vertical position of the upper edge of gill slit. Thoracic region and abdomen scaled; anus almost covered by scales. Lateral line complete, almost straight with anterior end slightly curved upwards.

Coloration and markings when fresh. See Fig. 2 . Body creamy yellow, dorsal side black, not reaching downward beyond lateral line. Scales with black spots posteriorly, forming irregular blotch patches. Rows of relatively regularly lined black spots aside lateral line, forming a vague lateral stripe. Head yellowish with dorsal side black until lower rim of orbit, ventral side until thoracic region white. Ventral side of body whitish yellow. A narrow, black marking just posterior to opercle, upper side narrow and round on lower side, width no more than one scale, shaping like an elongated teardrop, and upper end not extending upwards beyond lateral line ( Fig. 6A ). Dorsal fin yellowish orange with a large, tadpole-shaped blotch from base of second and third branched ray until covering tips of third unbranched ray to third branched ray ( Fig. 5A ). Pectoral fins, pelvic fins, and anal fin white with an orangish yellow shade medially, scattered with bits of pigmentation between branched rays. Caudal fin milky yellow with two stripes along unbranched rays on both lobes, scattered with bits of black spots between these stripes.

Colouration in preservatives. Body overall yellowish (caused by long-term preservations), all shades of color faded. All blotches remain intact, body with a lateral stripe extending from gill slits to caudal fin base. All fins whitish.

Remarks. The characters of having a vague lateral stripe and body mottled with black blotch patches can be employed to initially differentiate the new species Sarcocheilichthys hanjiangensis from its Chinese congeneric species, S. sinensis and S. lacustris (both having three to four large patches of transverse bands), and S. sciistius , S. parvus , and S. caobangensis (all three having clear lateral stripe extending from snout tip to caudal fin base). S. hanjiangensis can also be differentiated from S. kiangsiensis by its absence of barbels (vs. barbels present), fewer lateral line scales (37–39 vs. 42–44), higher pharyngeal teeth row counts (2 vs. 1), and a relatively robust head (20.26% in SL vs 25% in SL), and from S. hainanensis by having higher pharyngeal teeth row counts (2 vs. 1), lower predorsal scale counts (9–10 vs. 11–12), a shorter caudal peduncle length (20.59% in SL vs. 21.26% in SL), a greater caudal peduncle depth (12.94% in SL vs. 11.83% in SL), a lower lip lobe morphology (long and narrow vs. short, bulb-like) ( Fig. 4A; 4B ), dorsal fin markings (tadpole-like blotch vs. single stripe along unbranched ray) ( Fig. 5A; 5B ), and a post-opercle blotch pattern (narrow, elongated teardrop shape vs. slight oval shaped blotch below lateral line)( Fig. 6A; 6B ) ( Table 1 ; 2).

S. hanjiangensis is most similar to S. nigripinnis and S. davidi in overall fin ray and scale counts, body proportions, and pharyngeal teeth row counts. However, S. hanjiangensis can be distinguished from S. nigripinnis by its male anus morphology (having a finger-like protrusion vs. no such character), female ovipositor length (not reaching anal fin origin vs. extending beyond anal fin origin) and ovipositor opening morphology (single pore vs. pedal shaped) ( Fig. 7B; 7E ), dorsal fin markings (tadpole-like blotch vs. dusky, slightly pigmented) ( Fig. 5A; 5C ), body markings (vague lateral streak with patches of spots vs. large, connected patches of pigmentation) ( Fig. 1B ; 2 ), and post-opercle blotch pattern (narrow, elongated teardrop shape vs. thin, single blotch below lateral line) ( Fig. 6A; 6C ). S. hanjiangensis can be further distinguished from S. davidi by its lower lip lobe morphology (narrow and long, situated along lower jaw vs. slightly bulbish, anterior end pointing towards midline of lower jaw), dorsal fin markings (tadpole-like blotch vs. dusky, slightly pigmented), body markings (vague lateral streak with patches of spots vs. large, connected patches of pigmentation), and post-opercle blotch pattern (narrow, elongated teardrop shape vs. single thin blotch below lateral line).

Etymology. The specific name, hanjiangensis , refers to Hanjiang, a river system of Fujian Province that runs through Changtin County, where the types of the new species were collected.

Distribution. Sarcocheilichthys hanjiangensis sp. nov. has been known so far only from its type locality.

Figures

FIGURE 1. Specimens of Sarcocheilichthys hainanensis and S. nigripinnis examined.A. S. hainanensis, NTOUP2013-05-026, 85.14 mm SL, male; B. S. nigripinnis, NTOUP2014-10-014, 92.11 mm SL, male. Scale bar = 1 mm.

FIGURE 2. Fresh and preserved (lower) holotype of Sarcocheilichthys hanjiangensis, NTOUP2008-12-004, 53.02 mm SL, male. Scale bar = 1 mm.

FIGURE 3. Left pharyngeal teeth of S. hanjiangensis, holotype, NTOUP2008-12-005, 50.69 mm SL, male. Scale bar = 0.01 mm. Photo taken by WC Chen.

FIGURE 4. Lower lip of three Sarcocheilichthys species examined herein. A. S. hanjiangensis, holotype, NTOUP2008-12- 004, 53.02 mm SL, male; B. S. hainanensis, NTOUP2013-05-026, 85.14 mm SL, male; C. S. nigripinnis, NTOUP2014-10-014, 92.11 mm SL, male.

FIGURE 5. Dorsalfin markings ofthreeSarcocheilichthys species examined herein.A.S.hanjiangensis, holotype,NTOUP2008- 12-004, 53.02 mm SL, male; B. S. hainanensis, NTOUP2013-05-026, 85.14 mm SL, male; C. S. nigripinnis, NTOUP2014-10- 014, 92.11 mm SL, male. Scale bar = 0.1 mm.

FIGURE 6. Head of three Sarcocheilichthys species examined herein, showing tubercle and post-opercle marking patterns. A. S. hanjiangensis, paratype, NTOUP-2008-12-005, 57.94 mm SL, male; B. S. hainanensis, NTOUP-2013-05-026, 85.14 mm SL, male; C. S. nigripinnis, NTOUP-2014-10-014, 92.11 mm SL, male. Scale bar = 0.1 mm.

FIGURE 7. Anus and female ovipositor of three Sarcocheilichthys species examined herein, yellow arrow marks the position of anus, red arrow marks the finger-like protusions, green dot indicates anal fin origin, and yellow circle highlighting the opening of female ovipositor tube. A. S. hanjiangensis, holotype, NTOUP2008-12-004, 53.02 mm SL, male; B. S. hanjiangensis, paratype, NTOUP2008-12-005, 53.95 mm SL, female; C. S. hainanensis, NTOUP2013-05-026, 85.14 mm SL, male; D. S. nigripinnis, NTOUP2014-10-014, 92.11 mm SL, male; E. S. nigripinnis, NTOUP2014-10-014, 90.18 mm SL, female.