Yaoshania pachychilus ( Chen 1980b )

Yang, Jian, Kottelat, Maurice, Yang, Jun-Xing & Chen, Xiao-Yong, 2012, Yaoshania and Erromyzon kalotaenia, a new genus and a new species of balitorid loaches from Guangxi, China (Teleostei: Cypriniformes), Zootaxa 3586, pp. 173-186 : 175-179

Yaoshania pachychilus ( Chen 1980b)

Protomyzon pachychilus ( Chen 1980b) : 106, type locality: Dayaoshan Mountain, Jinxiu County, Xi Jiang (a tributary of the Pearl River); Yue 1981: 169; Chen & Zheng 1989: 249; Chen & Tang 2000: 477; Kottelat 2004: 301; Neely et al. 2007: 97; Kong et al. 2008: 243.

Material examined. IHB 8 , lectotype, 57.7 mm SL , IHB 7 , 12–14 , 4 paralectotypes 27.6–56.0 mm SL, Dayaoshan Mountain , Jinxiu County, Guangxi, China .— KIZ 200241648–200241649 , 200243055 , 200243060–200243061 , 200243063–200243064 , 200243068 , 200243080–200243081 , 200241655 , 11 , 34.4–51.2 mm SL, Meicun village ( Meicun river ) (24°08'23.0"N, 110°06'49.0"E), Jinxiu County, Guangxi, China; Kong De Ping, 11 April 2002 .— KIZ 2008007849 , 2008007851 , 2008007856 , 2008007857 , 4 , 19.0– 24.4 mm SL, Jinxiu County, Guangxi, China; Lan Jia Hu , 2008 .— KIZ 2002005610 , 2002005621 , 2002005648 , Shibajia, Jinxiu County, Guangxi, China; Kong De Ping , 2002 .— ZRC 53443, 4 , 15.0–23.0 mm SL; aquarium import, from China; don. P. Yap , 14 December 2011 .

Diagnosis. See generic diagnosis.

Description. Morphometric characters of Y. pachychilus are given in Table 1. See Figure 1 for general appearance and Figure 3A for ventral view of head.

Body moderately elongate, anterior part cylindrical, posterior part compressed. Head length greater than head width. Snout blunt. Anterior and posterior nostrils close together, anterior nostril with a short tubular flap. Eye small, 10.4–16.2% of head length, eye diameter shorter than gill opening length. Interorbital width shorter than snout length, 39.5–53.8% of head length. Gill opening large, its ventral extremity at lower extremity of pectoral-fin base. Mouth inferior, width 32.9–45.2% of head width. Rostral fold with four notches to accommodate rostral barbels; notches create three lobes of rostral fold; middle lobe largest, crescentic. A maxillary barbel at corner of mouth, longer than rostral barbels. A groove present between rostral fold and upper lip. Lip lamina at angle of mouth. A small fleshy lobe present posterior to each maxillary barbel on lower lip. Lips smooth, lower lip fleshy and laterally enlarged. Lower jaw arched, with radial grooves on surface.

Dorsal fin inserted posterior to midpoint of body, with 3 simple and 7 branched rays, longest dorsal-fin ray shorter than head length; pectoral fin with 1 simple and 16–17 branched rays; pectoral-fin length greater than head length, last 4 or 5 branched pectoral rays shorter, close to flank; tip of pectoral fin reaching two-thirds of distance between pectoral fin and pelvic-fin origins; pelvic-fin origin posterior or opposite to vertical through dorsal-fin origin, with 1 simple and 7–8 branched rays, tip of pelvic fin reaching anus; anal fin with 3 simple and 5 branched rays, reaching caudal-fin base. Caudal fin shallowly emarginate, lower lobe slightly longer than upper one. Lateral line complete, with 71–75 scales. No tubercles observed on side of body.

(mean±SD). Data for E. yangi and Y. pachychilus from Neely et al. (2007).

Coloration. After fixing in 10% formalin and storage in 75% ethanol, in juveniles (less than 27.6 mm SL), body pale yellowish with bold black marks: a black blotch at tip of snout and three broad black bars circling the body, one located between eye and midlength of pectoral fin, one between dorsal-fin origin and tip of dorsal fin, and one on posterior extremity of caudal peduncle, extending onto caudal fin in three triangular processes, one in the middle of the fin and one each along upper and lower edges. A black blotch at base of dorsal and pelvic fins. Anal-fin rays black. Coloration changing with increasing size, with bars becoming connected along dorsal midline and along middle of flank while at same time disappearing in intermediate areas. In adults, after fixation in 10% formalin and preservation in 75% alcohol, body background light yellow, markings dark brown to black. Head mottled leaving two yellow longitudinal stripes, one running from tip of snout, along nostrils, and ending at upper edge of eye; the other from side of snout to lower edge of eye. A bold black stripe (height less than 1/3 body depth) along lateral line; a thin black stripe from above dorsal side of pectoral-fin base, along pelvic-fin base, along analfin base, and ending at ventral extremity of caudal-fin base. Dorsum dark brown, with short band connecting to midlateral stripe, leaving a row of elongated yellow marks between them (between upper extremity of gill opening and upper part of caudal-fin base: Fig. 1). A light yellow mark across back at middle of base of dorsal fin, connected to series of yellow marks above midlateral stripe. One row of dark-brown spots on dorsal-fin rays, two rows on caudal-fin rays.

Distribution. Yaoshania pachychilus is presently known from three headwater streams (Meicun, Changtan and Dishui streams) on Dayaoshan Mountain, Guangxi, China ( Fig. 4).

Remarks. Yaoshania pachychilus was first described by Chen (1980a) based on seven syntypes, of which we were able to examine five: IHB 8, 57.7 mm SL is here designated as lectotype. IHB 7, 27.6 mm SL, is juvenile, IHB 8, IHB 12–14, 39.3–57.7 mm SL, are adults. IHB 8, the specimen in best condition, is apparently the one illustrated by Chen (1980a).

Fishes exported in 2011 by the aquarium fish trade from China as "panda loach" are apparently juveniles of Yaoshania pachychilus . Four specimens obtained in Singapore ( ZRC 53443, 4 ex., 15.0–23.0 mm SL) were examined and the lips show the lip lamina already completely formed ( Fig. 5) .