Sinocyclocheilus xingrenensis Luo, Xiao, Zhou, Xiao & Zhou, 2025

Sinocyclocheilus xingrenensis Luo, Xiao, Zhou, Xiao & Zhou sp. nov.

Fig. 4 View Figure 4 , Table 4 View Table 4

Chresonymy.

Sinocyclocheilus gaowuensis : Liu 2018 (Xingren City, Guizhou Province, China).

Material examined.

Holotype. • GZNU 20190508001 , total length 149.4 mm (TL), standard length 123.5 mm (SL), collected by Jia-Jun-Zhou on May 8, 2019, in Yangsitun Village , Tianba Community, Xingren City, Guizhou Province, China (25.41255686 ° N, 105.21536082 ° E; ca. 1323 m a. s. l.). GoogleMaps

Paratypes. • Six specimens from the same locality as the holotype: GZNU 20190508002 – GZNU 20190508007 , 79.7–123.5 mm SL, collected by Jia-Jun-Zhou on May 8, 2019 GoogleMaps ; GZNU 201250907001 , 69.5 mm SL, collected by Tao Liu on September 7, 2012, in Gaowu Village , Xiashan Town, Xingren City, Guizhou Province, China (25.52536100 ° N, 105.20758400 ° E; ca. 1415 m a. s. l.) GoogleMaps .

Diagnosis.

Sinocyclocheilus xingrenensis sp. nov. can be distinguished from its congeners by a combination of the following characteristics: (1) absence of horn-like structures and indistinct elevation at the head-dorsal junction; (2) body scaleless, with irregular black markings scattered above the lateral line; (3) eyes large, diameter 16–21 % of head length; (4) dorsal-fin rays, iii, 6–7, last unbranched ray serrate along posterior margin; (5) tip of the pectoral fin not reaching the pelvic fin origin; (6) pelvic fin rays, i, 8, tip not reaching the anus; (7) lateral line complete and curved, with pores 65–77; (8) tip of maxillary barbel reaching the anterior margin of the operculum; (9) six rakers on the first gill arch. The major diagnostic characters for new species and related species are summarized in Table 3 View Table 3 .

Description.

Body fusiform, moderately elongated and compressed. Dorsal profile convex from nape to dorsal fin; body maximum depth positioned at insertion of dorsal fin; ventral profile slightly concave, tapering gradually toward the caudal fin.

Head short, length, 26–29 % of SL, slightly compressed, head length greater than width. Eyes large, eye diameter 16–21 % of HL, interorbital distance greater than distance between posterior nostrils. Snout short, U-shaped, and projecting beyond lower jaw in dorsal view, less than half HL. Mouth subinferior and arched, with slightly projecting lower jaw. Two pairs of nostrils, anterior nostril close to posterior nostril, nares at about 1 / 3 between snout tip and anterior margin of eye; anterior nostril short tubular, posterior margin of short tube with posterior flap, forward to cover mouth of tube; posterior nostril subcircular, open. Two pairs of barbels; rostral barbels not reaching the anterior margin of operculum when extended backward; maxillary barbel slightly shorter compared with rostral barbel, tips beyond the eye but reaching anterior margin of operculum when extended backward. Gill opening moderate, opercular membranes connected at isthmus. Six outer rakers on first gill arch. Pharyngeal teeth in three rows with counts of 2, 3, 4–4, 3, 2; pharyngeal teeth strong and well developed, with curved and pointed tips.

Dorsal-fin rays iii, 6–7; pectoral-fin rays i, 12–16; pelvic-fin rays i, 8; anal-fin rays iii, 5; and 15–18 branched caudal-fin rays. Dorsal fin short, 19–24 % of SL, less than head length, 67–88 % of HL; distal margin truncated, origin opposite to pelvic-fin origin, situated slightly anterior to midpoint between snout tip and caudal-fin base; last unbranched ray strong, softening toward tip, with serrations along posterior margin; first branched ray longest, shorter than HL, tip beyond the vertical of the anus. Pectoral fin short, distal margin truncated, length slightly smaller than HL, 18–22 % of SL, tips beyond 3 / 4 of the distance between pectoral-fin origin and pelvic-fin origin, tips not reaching the pelvic-fin origin. Pelvic fin moderately developed, distal margin rounded, length 14–17 % of SL, and tips not reaching the anus. Anal fin short, 14–17 % of SL, distal margin rounded, origin close to the anus, a short distance between the origin and the anus, tips not reaching the caudal fin base. Caudal peduncle length 18–23 % of SL, depth 47–67 % of body depth. Caudal fin forked, upper lobe equal in length to the lower one, tips truncated.

Body scaleless. Lateral line complete and slightly curved, with pores 65–77, originating from upper margin of operculum and extending to end of caudal peduncle. With about 30 to 58 irregular black markings scattered above the lateral line, almost in a straight line, and a large black spot in the center of the end of the caudal peduncle.

Coloration and variation.

In life, the body is golden yellow overall, with white pectoral fins and a slightly translucent white dorsal fin; the gills are blackish, with numerous black markings on the back and a relatively large black spot at the caudal fin base (Fig. 5 View Figure 5 ). In 7 % formalin solution, the specimens are dark gray above the lateral line and white below the lateral line, with each fin yellowish white (Fig. 4 View Figure 4 ). Most specimens are consistent in their morphological characteristics, except for specimen GZNU 20190508004 , where the lateral line separates backward into two from the upper pectoral fin and converges at the base of the caudal fin.

Distribution.

Sinocyclocheilus xingrenensis sp. nov. is found only in caves near Xingren City, Guizhou, China, including the type locality and from Gaowu Village, Xiashan Town, Xingren City. Much ecological information about the new species is currently unknown. The discovery site belongs to the Beipanjiang River basin.

Etymology.

The specific epithet “ xingrenensis ” refers to the type locality of the new species: Xingren City, Guizhou Province, China. We propose the common English name “ Xingren Golden-lined Fish ” and the Chinese name “ Xīng Rén Jīn Xiàn Bā (兴仁金线鲃) ”.