Yunnanilus jiuchiensis, Du & Hou & Chen & Yang, 2018

Du, Li-Na, Hou, Mian, Chen, Xiao-Yong & Yang, Jun-Xing, 2018, A new species of Yunnanilus (Cypriniformes: Nemacheilidae) from Sichuan, southwest China, Zootaxa 4532 (1), pp. 137-144 : 138-140

Yunnanilus jiuchiensis sp. nov.

( Figs. 1–3 )

Holotype. KIZ2018000002 , 35.3 mm SL; China, Sichuan Province, Pengzhou City, Jiuchi County, Tuojiang River , 30.9876° N, 104.0484° E; collected by Y. Shen in March 2018.

Paratypes. 8 ex. KIZ2018000001 , 0003–9 , 29.6 – 37.4 mm SL ; same data as holotype .

Diagnosis. The new species is placed within Yunnanilus as it possesses the diagnostic characters listed in Kottelat & Chu (1988). Yunnanilus jiuchiensis is distinguished from all other members of the genus by the following characters: processus dentiformis absent; body covered with scarce scales, except thoracic area between pectoral and pelvic fins; 8 inner gill rakers on first gill arch; eye diameter larger than interorbital width; length of caudal peduncle less than its depth; lateral head length 25.1–27.8% SL; and interorbital 20.2–24.3% of lateral head length.

Description. Morphometric and meristic data presented in Table 1. Dorsal-fin rays iii, 8; anal-fin rays iii, 6; pectoral-fin rays i, 11; pelvic-fin rays i, 6; branched caudal-fin rays 15–16; outer gill rakers absent, 8 inner gill rakers on first gill arch; cephalic lateral-line canals with 6 or 7 supraorbitals, 3+12 infraorbitals, 2+2 supratemporals, and 6–10 mandibular pores ( Fig. 2 ). Lateral line incomplete, as long as half the length of the pectoral-fin length, with 6–11 pores.

Body slender. Anterior part of body to dorsal-fin origin cylindrical; caudal peduncle laterally compressed; abdomen smooth and scaleless. Deepest point of body usually anterior to dorsal-fin origin. Head depth greater than width. Snout length less than postorbital length. Anterior and posterior nostrils widely separated, anterior nostril at tip of tube. Eyes normally developed, not reduced like in cave fish; eye diameter larger than interorbital width, interorbital space slightly convex. Mouth inferior. Upper lip smooth with slight median incision; lower lip with median incision, two lobes on each side. Processus dentiformis absent. Three pairs of barbels; inner rostral barbels reaching halfway to mouth corner; outer rostral barbels reaching mouth corner; maxillary barbels reaching posterior edge of eye.

Dorsal fin truncate, origin closer to caudal-fin base than to snout tip. Anal-fin truncate, tip reaching hypural plate. Pectoral-fin length 50.6–64.1% of distance between pectoral- and pelvic-fin origins when adpressed; pelvicfin origin slightly posterior to vertical through dorsal-fin origin. Tip of pelvic fin not reaching anus when adpressed; pelvic-fin origin closer to anal-fin origin than pectoral-fin origin. Anus closer to anal-fin origin than posterior insertion of pelvic fin. Caudal-peduncle length less than its depth. Caudal fin emarginated.

Body covered with scarce scales, except on ventral area between pectoral and pelvic fins. Air-bladder with two chambers; anterior chamber of swim bladder enclosed in bony capsule and large free posterior chamber filling body cavity to dorsal-fin origin, contacting anterior capsule by slender tube; tube length one third of posterior chamber length. Intestine straight.

Color pattern in formalin. In both sexes, body yellowish or grey yellowish; fins without blotches. In females, upper two-thirds of body and head covered by large brown blotches; faint longitudinal stripe along lateral line; several irregular brown blotches on dorsum, sometimes dorsal blotch connected with lateral blotch and bar ( Fig. 1A ). In males, body with black longitudinal stripe on both sides; without other markings observed in females ( Fig. 1B ).

Distribution and habitat. Yunnanilus jiuchiensis inhabits a tributary of the Tuojiang River, Yangtze River basin, with mud/cobble substrate in Jiuchi County, Pengzhou City, Sichuan Province, China ( Fig. 3 ). The stream is slow-flowing with dense macrophytes.

Etymology. The specific name, jiuchiensis , is derived from Jiuchi County, where the type specimens were collected.

Figures

FIGURE 1. Lateral views of Yunnanensis jiuchiensis sp. nov., A. holotype, KIZ 2018000002, 35.3 mm SL, female; B. paratype, KIZ 2018000009, 32.3 mm SL, male. Scale = 1 mm.

FIGURE 2. Head sensory pores: n.b., nostril barbel; A1+A2, infraorbital canal; B, supraorbital canal; C, supratemporal canal; D, preoperculomandibular canal. Scale = 1 mm (methods followed Kottelat, 1984).

FIGURE 3. Type locality (▲) of Yunnailus jiuchiensis in Sichuan Province, China. Gray area is Sichuan Province.