Sinocyclocheilus xiejiahuai Luo, Fan, Xiao & Zhou, 2024

Fan, Cui, Wang, Man, Wang, Jia-Jia, Luo, Tao, Zhou, Jia-Jun, Xiao, Ning & Zhou, Jiang, 2024, Sinocyclocheilus xiejiahuai (Cypriniformes, Cyprinidae), a new cave fish with extremely small population size from western Guizhou, China, ZooKeys 1214, pp. 119-141 : 119-141

Sinocyclocheilus xiejiahuai Luo, Fan, Xiao & Zhou sp. nov.

Fig. 4 , Table 5

Material examined.

Holotype. GZNU 20230304001 , total length 242.8 mm (TL), standard length 201.8 mm (SL), • Hongguo Town , Panzhou City, Guizhou Province, China; 25.6576 ° N, 104.4044 ° E; ca 1852 m a. s. l.; collected on October 2, 2021.

Diagnosis.

Sinocyclocheilus xiejiahuai sp. nov. can be distinguished from all other congeners by the following combination of characters: (1) absence of horn-like structures and indistinct elevation at the head-dorsal junction; (2) absence of irregular black markings on the body lateral and scaleless; (3) eyes large, eye diameter 13 % of head length; (4) dorsal-fin rays, iii, 6 ½, last unbranched ray strong, with serrations along posterior margin; (5) pectoral-fin rays, i, 13; (6) anal-fin rays, iii, 5; (7) pelvic-fin rays, i, 7; (8) lateral line pores 74; (9) gill rakers well developed, nine on first gill arch; (10) pectoral fins short, tip not reaching to pelvic-fin origin (Table 5 ).

Description.

Body fusiform, moderately elongate and compressed. Dorsal profile convex from nape to dorsal-fin, greatest body depth at dorsal-fin insertion, ventral profile slightly concave, tapering gradually toward the caudal-fin, greatest body depth slightly anterior to dorsal-fin insertion.

Head short, compressed laterally, length longer than maximum head width, depth longer than maximum head width. Eyes present, eye diameter 13 % of head length (HL), interorbital distance larger than distance between posterior nostrils. Snout short, U-shaped, and projecting beyond lower jaw in dorsal view, length 37 % of HL. Mouth subterminal, with slightly projecting upper jaw. Two pairs of nostrils, anterior and posterior nostrils close set, nares at 2 / 3 between snout tip and anterior margin of eye, anterior nares possessing an anterior rim with a posterior fleshy flap forming a half-tube. Two pairs of barbels, rostral barbels short, not reaching the anterior edge of operculum when extended backwards, maxillary barbel slightly long compared to rostral barbel, beyond the anterior edge of operculum when extended backwards (Table 5 ).

Dorsal fin rays iii, 6 ½, pectoral fin rays i, 13, pelvic fin rays i, 7, anal fin rays iii, 5, and 13 branched caudal fin rays. Dorsal fin long, 24 % of SL, less than head length, distal margin truncated, origin posterior to pelvic fin insertion, situated slightly anterior to midpoint between snout tip and the caudal fin base, last unbranched ray strong, softening toward tip, with serrations along posterior margin, first branched ray longest, shorter than HL, tip reaching to the vertical of the anus. Pectoral fin developed, distal margin rounded, length slightly small than HL, 16 % of SL, tips beyond 2 / 3 of the distance between pectoral-fin origin and pelvic-fin origin, tips not reaching to pelvic fin-origin. Pelvic fin moderately developed, distal margin rounded, length 14 % of SL, and tips not reaching to anus. Anal fin short, 15 % of SL, distal margin truncated, origin close to the anus, tips not reaching to caudal fin base. Caudal peduncle well developed, length 52.4 mm, depth 23.4 mm, and without adipose crests along both dorsal and ventral sides. Caudal fin slight forked, upper lobe equal in length to the lower one, tips rounded.

Body non-scale, lateral line pores 74. Complete lateral line, slightly curved, curved downward at the anus position, originating from posterior margin of operculum and extending to end of caudal peduncle.

Coloration.

In 7 % formalin solution, the specimen was grayish brown overall, with each fin pale yellow.

Geographical distribution and habitat.

Sinocyclocheilus xiejiahuai sp. nov. is the only vertical cave found at an altitude of 2276 m in Hongguo Town, Panzhou City, Guizhou Province, China, some distance away. The discovery site is within the Beipanjiang River Basin (Fig. 1 ). There is no light in the cave. Individuals were distributed in a small pool ~ 25 m from the cave entrance. The pool is ~ 1.8 m wide and 80 cm deep, and the water temperature at the time of collection was ~ 16 ° C and pH 7.4. Inside the cave, the species of S. xiejiahuai sp. nov. is symbiotic with S. longicornus ( S. angularis group) and Triplophysa panzhouensis . The arable land outside the cave is mainly cultivated with maize, wheat, and potatoes.

Etymology.

The specific name xiejiahuai is in honor of Professor Jia-Hua Xie (谢家骅), for his contribution to zoological research in China. Before retiring from Guizhou Normal University, he described S. angustiporus , the first species distributed in Guizhou within the S. tingi species group, and his work has been an important contribution to the study of zoology in Guizhou, especially the conservation of critically endangered species. We propose the common English name “ Xie’s Golden-lined Fish ” and the Chinese name “ Xiè Shì Jīn Xiàn Bā (谢氏金线鲃). ”

Figures

Figure 1. Sampling collection localities and distribution of the Sinocyclocheilus xiejiahuai sp. nov. and 26 species of the S. tingi species group of the genus Sinocyclocheilus in southwest China. The base maps are from Standard Map Service website (http://211.159.153.75/).

Figure 4. Lateral view of adult holotype GZNU 20230304001 of Sinocyclocheilus xiejiahuai sp. nov. in preservative A left side B right side.