Yunnanilus yangi, He & Li & Che & Yang & Wang & Wang, 2024

He, Yun-Rui, Li, Xue-Rong, Che, Xing-Jin, Yang, Xiao-Jun, Wang, Ji-Shan & Wang, Mo, 2024, A new species of Yunnanilus (Cypriniformes: Nemacheilidae) from upper Pearl River, Yunnan, China, Zootaxa (Zool. Res.) 5428 (2), pp. 194-206 : 195-199

Yunnanilus yangi sp. nov.

http://zoobank.org/ EA4BBD95-A90D-4D13-AACE-0FA81D0B5965

Figs 1–6 ; Table 1 .

Holotype. SWFU-C2022040110 , 57.1 mm standard length (SL); collected by YR He and XR Li on 21 st April 2022 at Long Dragon Spring , Xinshao Town , Mile City, Yunnan Province, China; Upper Pearl River (Nanpan Jiang) (24°20′05.69″N, 103°21′29.78″E; ca 1384 m).

Paratypes. SWFU-DS2022040010DS2022040012 , SWFU-C2022080268-C2022080281 , 42.4-59.2 mm standard length (SL); collected by YR He, XR Li and JM Bai on 24 th April 2022 and 16 th August 2022 at Big Tree Dragon Spring and Long Dragon Spring , Miyang Town and Xinshao Town , Mile City, Yunnan Province, China; Upper Pearl River (Nanpan Jiang) (24°20′05.69″N, 103°21′29.78″E; ca 1384 m; 24°26′00.54″N, 103°24′13.53″E; ca 1472 m) .

Diagnosis. Yunnanilus yangi sp. nov. can be distinguished from other species of Yunnanilus by the following combinative characteristics: (1) branched caudal-fin rays 16; (2) pelvic-fin rays i, 6-7; (3) upper lip with median incision; (4) upper jaw without processus dentiformis; (5) body scaleless; (6) eye diameter smaller than interorbital width; (7) dorsal-fin origin closer to snout tip base than to caudal-fin base; and (8) caudal peduncle depth less than caudal peduncle length.

Description. Morphometric and meristic data presented in Table 1 . Body slender. Anterior part of body to dorsal-fin origin cylindrical; caudal peduncle laterally compressed. Deepest point of body usually anterior to dorsal-fin origin. Head depth greater than width. Snout length longer than postorbital length.Anterior and posterior nostrils widely separated, and the distance between them is larger than distance from posterior nostril to anterior margin of eye, the anterior nostrils tube-like, and not being elongated into a barbel-like structure. Eyes of medium size and normally developed, eye diameter smaller than interorbital width. Mouth inferior. Upper lip with median incision; lower lip incised medially, with two lobes on each side and free. Upper jaw without processus dentiformis; lower jaw smooth. Three pairs of barbels; inner rostral barbel reaching anterior nostril; outer rostral barbel reaching posterior nostril; maxillary barbel reaching posterior margin of eye.

Dorsal-fin rays iii, 8; anal-fin rays ii, 5; pectoral-fin rays i, 11; pelvic-fin rays i, 6-7; branched caudal-fin rays 16. Lateral line incomplete, with the end reaching insertion of the dorsal fin.

Dorsal-fin truncate, origin closer to snout tip base than to caudal-fin base. Predorsal length 48.0%-55.0% SL. Anal-fin truncate, tip not reaching caudal-fin base. Pelvic-fin origin slightly behind dorsal-fin origin, tip of pelvic fin not reaching anus. Pelvic-fin origin closer to anal-fin origin than pectoral-fin origin. Caudal peduncle depth less than caudal peduncle length. Caudal fin emarginate.

Body scaleless. Air bladder with two chambers; anterior chamber enclosed in bony capsule, posterior chamber large and oval, filling body cavity to dorsal-fin origin.

Coloration of preserved specimens. Head and body with yellowish background colored and brown pattern. Head brown on top to lower margin of eye or with spotted pattern, cheeks and ventral head surface without colored pattern. Pre-dorsal brown or with irregular cloud-like patches. Brown patches on upper caudal peduncle, fused with blotches on flank forming in few individuals. Flank below line between pectoral-fin base and anus without pattern. There are multiple dark brown, irregularly shaped, vertically elongated cloud-like blotches along lateral midline. One distinct, small, roundish or comma-shaped, black spot at upper and lower posterior extremity of caudal peduncle. At the upper and lower posterior extremity of the caudal peduncle, there is one distinct small, roundish or comma-shaped black spot. In some individuals, the upper and lower black spots are connected. Dorsal fin and caudal fin with brown bands of small, elongated blotches on fin-rays. Anal-, pelvic- and pectoral fins hyaline ( Fig 1 ).

Etymology. The name of the new species, yangi , dedicated to Dr. JunXing Yang for his outstanding contribution to fish diversity conservation in Yunnan Province, and thus the Chinese name of this new species is “杨氏云南#” (Yáng shì yún nán qiű).

Distribution. Specimens were collected from Big Tree Dragon Spring and Long Dragon Spring belonging to Upper Pearl River (Nanpan Jiang) ( Fig. 3 , 4 ). The water of Long Dragon Spring is limpid, with depth greater than 3 m ( Fig. 3A ). The water of Big Tree Dragon Spring is also limpid, with many aquatic plants in the water and a depth greater than 5 m ( Fig. 3B ). Species of Sinocyclocheilus sp. and Discogobio sp. were also found in these springs.

Figures

FIGURE 1. Lateral, X-ray, ventral and dorsal views of Yunnanilus yangi sp. nov. Holotype, SWFU-C2022040110, 57.1 mm SL: A, Lateral view; B: X-ray view; C: ventral view; D: dorsal view.

FIGURE 2. Lips structures of Yunnanilus paludosus and Yunnanilus yangi sp. nov. Holotype, KIZ1980001276 (from Kunming Natural History Museum of Zoology); Holotype, SWFU-C2022040110: A: Yunnanilus paludosus; B: Yunnanilus yangi sp. nov.

FIGURE 3. Habitat of Yunnanilus yangi sp. nov.: A: Long Dragon Spring; B: Big Tree Dragon Spring.

FIGURE 4. Sampling distribution map of Yunnanilus yangi sp. nov.

FIGURE 5. Phylogenetic position of Yunnanilus yangi sp. nov. based on BI

FIGURE 6. Principal component analysis (PCA) results of Yunnanilus distributed in the Pearl River

Tables

TABLE 1. Morphometric and meristic data of Yunnanilus yangi sp. nov. Range, mean, and standard deviation (Mean±SD) include holotype values.

Character	Holotype	Range (n =17)	Mean± SD
Dorsal-fin rays	iii, 8	iii, 8
Pelvic-fin rays	i, 6	i, 6-7
Pectoral-fin rays	i, 11	i, 11
Anal-fin rays	ii, 5	ii, 5
Branched caudal rays	16	16
Total length (mm)	70.6	53.1-73.6	65.3±5.0
Standard body length (mm)	57.1	42.4-59.2	52.6±4.2
Percent of standard length
Body depth	23.5	16.3-21.1	19.0±1.2
Predorsal length	54.7	47.5-55.0	51.5±2.0
Dorsal-fin length	24.3	22.6-26.2	24.4±1.0
Preanal length	77.0	74.3-80.5	77.7±1.7
Anal-fin length	15.9	14.9-17.6	16.2±0.8
Pectoral-fin length	19.2	13.4-18.8	17.2±1.2
Pelvic-fin length	15.8	13.2-16.5	15.2±0.8
Caudal peduncle length	14.9	11.3-17.6	14.6±1.4
Caudal peduncle depth	9.2	7.7-9.0	8.2±0.4
Head length	20.0	17.5-21.0	19.6±0.9
Percentage of head length
Head depth	73.8	65.2-78.9	71.3±3.7
Head width	67.3	54.1-65.6	58.1±3.0
Snout length	46.0	39.2-53.5	44.3±3.3
Eye diameter	29.2	20.8-29.1	23.3±2.3
Interorbital width	30.6	23.3-30.9	26.4±2.2
Percent of caudal peduncle length
Caudal peduncle depth	61.7	47.0-74.2	56.5±6.2