Claea scet, Lei & He & Huang & Zhou & He, 2025

Lei, Hao-Tian, He, Li, Huang, Jun-Hao, Zhou, Jia-Jun & He, De-Kui, 2025, Description of a new cave-dwelling species of Claea (Teleostei, Cypriniformes, Nemacheilidae) from the Yangtze River basin in Sichuan, southern China, Zoosystematics and Evolution 101 (2), pp. 681-695 : 681-695

publication ID	https://doi.org/10.3897/zse.101.146469
publication LSID	lsid:zoobank.org:pub:DA08B820-ACC8-4F3D-B098-E446674360C4
DOI	https://doi.org/10.5281/zenodo.15089900
persistent identifier	https://treatment.plazi.org/id/DD63F2B6-96CD-5C12-BA14-55760FACDCB5
treatment provided by	Zoosystematics and Evolution by Pensoft
scientific name	Claea scet
status	sp. nov.

Treatment

Claea scet sp. nov.

Holotype.

• IHB 202305300005 About IHB , 51.3 mm SL; a subterranean tributary of the Dadu River in the Yangtze River drainage in Taojin Cave , Shiqianggou, Hulu Town, Shawan District, Leshan City, Sichuan Province, China (29°30'2"N, 103°63'6"E; 570 m elevation); collected by Li He & Ze-Yu Li, 28. V. 2023.

Paratypes.

• IHB 202305300001 –202305300004, IHB 202305300006 –202305300009, 8, 43.1–56.4 mm SL; other data same as holotype ; • IHB 202305300010 –202305300016, 7, 34.2–58.9 mm SL; same locality as holotype, collected by Yuan Li & Ze-Yu Li, VI- 16-2024 .

Diagnosis.

C. scet resembles all known species of Claea in possessing a processus dentiformis at the medium of the upper jaw, absence of tubercle-bearing, elevated skin on the sides of the head and a thickened tuberculated pad on the dorsal surface of the thickened and widened rays of the pectoral fin in males, absence of adipose crest between dorsal fin and caudal fin base, body scaleless, and absence of supra-pelvic flap, all of which are diagnostic features of Claea . C. scet can be distinguished from C. dabryi , C. minibarba and C. wulongensis by the combination of the following characters (see Table 2 View Table 2 ): Processus dentiformis reduced, not covering lower jaw when mouth shut; eye vestigial, diameter of eye 3.8–5.9 % SL; short anal fin, anal fin height 7.0–8.4 % SL. C. scet is further distinguished from C. dabryi by shorter maxillary barbels (22.4–27.5 % SL vs. 29.8–47.4 % SL) and shorter outer rostral barbels (23.0–29.8 % SL vs. 30.2–47.5 % SL). C. scet is further distinguished from C. minibarba by a more depressed body (body depth 10.1–13.5 % SL vs. 14.7–17.6 % SL), a more posteriorly situated pelvic fin (prepelvic length 51.7–56.0 % SL vs. 47.7–50.6 % SL), a longer pectoral fin (17.6–20.2 % SL vs. 15.0–17.6 % SL), a shallower caudal peduncle (5.5–8.5 % SL vs. 9.5–11.7 % SL) and a more elongated head (head depth 41.4–46.5 % HL vs. 55.5–59.4 % HL and head width 52.3–60.3 % HL vs. 61.5–68.0 % HL). C. scet is further distinguished from C. wulongensis by a more posteriorly situated pelvic fin (prepelvic length 51.7–56.0 % SL vs. 48.3–50.9 % SL), a longer anal fin base (8.4–9.6 % SL vs. 6.6–8.2 % SL), more closely situated eyes (interorbital length 23.5–31.9 % HL vs. 38.5–43.1 % HL).

Description.

Morphometric data for 16 type specimens of C. scet are provided in Suppl. material 1. Juvenile individuals with a standard length (SL) of less than 40 mm were excluded from morphological comparisons with congeners (Table 2 View Table 2 ). The general body profile is illustrated in Fig. 1 View Figure 1 . The body is elongated, subcylindrical anteriorly, and laterally compressed posteriorly. The dorsal profile of the head is nearly straight, while the dorsal profile of the body is convex. The ventral profile is almost straight from the snout tip to the anal fin origin, with a slight concavity posterior to the anal fin origin. The greatest body depth occurs anterior to the dorsal fin origin, gradually decreasing toward the caudal fin base. The body is entirely scaleless and smooth, with a complete and straight lateral line. The cephalic lateral line system comprises 3 + 8 infraorbital, 6 supraorbital, 3 supratemporal, and 10 preopercular-mandibular pores (Fig. 2 View Figure 2 ).

The head is moderately depressed, longer than wide, and wider than deep. The snout is pointed, with a snout length measuring 38.1–44.7 % of the head length (HL). The eyes are reduced, with a diameter of 3.8–5.9 % HL, and are positioned dorsolaterally on the head. Both anterior and posterior nostrils are closely situated; the anterior nostril is housed in a short tube with an elongated, tube-like tip that does not reach the anterior margin of the eye. The mouth is inferior and curved, with thin lips exhibiting shallow surface furrows. The upper lip is complete and connected to the lower lip at the corners of the mouth. The lower lip features a distinct V-shaped median incision. The upper and lower jaws are arched, with a weakly developed processus dentiformis on the upper jaw compared to congeners (Figs 2 View Figure 2 , 3 View Figure 3 ), not covering the lower jaw when mouth is shut. Three pairs of barbels are present: two pairs of rostral barbels (the inner pair not reaching the corner of the mouth, and the outer pair slightly longer than the inner pair) and one pair of maxillary barbels, which extend to the posterior margin of the eye when fully extended (Fig. 2 View Figure 2 ).

Dorsal fin with 3 simple and 8 (n = 12) or 9 (n = 4) branched fin rays, origin behind mid-point between snout tip and caudal-fin base and posterior to the pelvic fin origin, distal margin truncate, length of dorsal fin greater than body depth. Pelvic fins with 1 simple and 5 (n = 1) or 6 (n = 15) branched fin rays, origin closer to anal fin origin than pectoral fin origin, tips of pelvic fins not reaching anus. Pectoral fins with 1 simple and 10 branched fin rays, extending beyond the halfway to pelvic-fin origin. Anal fin with 3 simple and 5 (n = 7) or 6 (n = 8) branched fin rays, origin closer to pelvic-fin insertion than to caudal fin base. Caudal fin forked, with 2 simple and 16 branched fin rays, the upper lobe slightly longer than the lower (Figs 1 View Figure 1 , 6 View Figure 6 ).

Intestine short, without bend or loops immediately posterior to stomach. Bony capsule of the air bladder large and thin, dumbbell-shaped, (Fig. 5 View Figure 5 ), posterior chamber of air bladder degenerated. Vertebrae 4 + 38 (Fig. 4 View Figure 4 ).

Coloration.

In their natural subterranean aquatic habitats, live specimens exhibit a general body coloration of light gray with a faint pinkish hue, accompanied by sparse pigmentation distributed laterally and dorsally. The ventral region is semi-transparent, while all fins appear hyaline. In specimens preserved in 10 % formalin, the body coloration transitions to light gray with a moderate yellowish tint, and pigmentation is observed to fade in some individuals (Figs 1 View Figure 1 , 6 View Figure 6 ).

Distribution.

This species is presently only known from a subterranean tributary of the Dadu River in the upper Yangtze River in Taojin Cave, Shiqianggou, Hulu Town, Shawan District, Leshan City, Sichuan Province, China (Figs 7 View Figure 7 , 9 View Figure 9 ).

Etymology.

The specific name “ scet ” is in reference to the abbreviation of Sichuan Cave Exploration Team, a cave exploration team who collected the type specimens, in recognition of their contributions to the understanding of cave fishes of Sichuan Province. “ 川洞山鳅 (Pinyin: Chuan Dong Shan Qiu) ” is proposed for the Chinese common name of this new species.

Field notes.

The Taojin Dolomite Cave, situated adjacent to a backroad in Shiqianggou, is characterized as a shaft-type cave with a broad entrance. Access to the cave is restricted to the Single Rope Technique (SRT) for descent. During the rainy season, elevated water levels render the cave inaccessible, while at other times, the interior remains humid with spacious tunnels. This species inhabits pools located within the deep dark zone of the cave, where environmental conditions during the survey period in May 2023 included an air temperature of 18–19 ° C and a water temperature of 15 ° C (Fig. 7 View Figure 7 ). Other troglobites found inside the same cave were Jujiroa duqianae Tian & He, 2023 ( Coleoptera , Carabidae ), Paratachys sp. ( Coleoptera , Carabidae ), Domene lizeyui Wang & He, 2024 ( Coleoptera , Staphylinidae ), Epanerchodus sp. ( Polydesmida , Polydesmidae ), and Chetoneura sp. ( Diptera , Keroplatidae ).