Schistura alboguttata, Cao & Zhang, 2018

Cao, Liang & Zhang, E., 2018, Schistura alboguttata, a new loach species of the family Nemacheilidae (Pisces: Cypriniformes) from the Pearl River basin in Guangxi, South China, Zootaxa 4471 (1), pp. 125-136 : 127-132

Schistura alboguttata , sp. nov.

( Fig. 1–4 )

Holotype. IHB2008050102 , 65.9 mm SL, from the Leli-He, flowing into the You-Jiang of the upper Pearl River basin at Leli Town , Tianlin County, Guangxi Province, South China, about 24°17'44" N, 106°13'33" E, at an altitude of 310 m above sea level; collected by E Zhang and Liang Cao in May, 2008.

Paratypes. IHB2008050101, IHB2008050103–7, 6 specimens, 59.2–76.5 mm SL; same collection data as holotype.

Diagnosis. Schistura alboguttata can be distinguished from all currently identified Chinese congeners by its unique body coloration consisting of irregular white spots scattered over the dorsal and lateral aspects of the body, and sometimes the predorsal region covered by irregular bars with narrow interspaces. The following characters, not unique to the new species, but utilized to distinguish it from other species, include: processus dentiformis welldeveloped; lower jaw with a remarkable median notch; no suborbital flap; lateral line complete; pelvic fin inserted anterior to vertical through dorsal-fin origin; caudal fin emarginated; caudal-peduncle length 1.2–1.3 times depth; black bar at caudal fin continuous and reaching dorsal and ventral midlines.

Description. Morphometric data are summarized in Table 2. Body anteriorly rounded and posteriorly compressed laterally toward caudal-fin base. Dorsal profile of head drastically sloping downward in front of anterior margin of eye; from there to posterior edge of cranium nearly straight. Dorsal profile of body convex. Body depth increasing to its maximum before dorsal-fin origin; slightly declining towards caudal-fin base. Ventral profile of head and prepelvic body nearly straight, slightly concave between pelvic-fin insertion and anal-fin origin, nearly straight in caudal peduncle. Dorsal and lateral body scales deeply embedded under skin; breast and belly scaleless. Lateral line complete.

Head depressed, wider than deep. Snout pointedly rounded when viewed dorsally, blunt when viewed laterally; cheeks greatly inflated in larger individuals. Eyes small, situated dorso-laterally near top of head, usually in anterior half of head; invisible when viewed ventrally. Mouth inferior and curved. Lips thin; processus dentiformis well-developed; lower lip with median interruption and 3–5 furrows on each side, marked corresponding median notch present in lower jaw. Anterior nostrils close to posterior one and pierced in front side of flap-like tube. Inner rostral barbel nearly reaching corner of mouth, outer one not reaching anterior margin of eye; maxillary one surpassing vertical of hind margin of eye ( Fig. 2 ).

Fins flexible; D. iii, 8; P. i, 10–11; V. i, 6–7; A. iii, 5; C. 8+8 branched rays. Dorsal-fin origin closer to caudalfin base than to tip of snout, distal margin straight or slightly convex. Pectoral-fin inserted at vertical through posteriormost point of operculum origin, adpressed fin reaching nearly halfway to pelvic-fin insertion. Pelvic fin inserted anterior to vertical through dorsal-fin origin, adpressed tip reaching or not reaching anus. Axillary pelvic lobe present. Anal fin with straight distal edge, tip of adpressed fin not reaching caudal-fin base. Caudal-fin somewhat emarginated, upper lobe as long as lower one. Caudal peduncle length 1.2–1.3 times its depth. Caudal adipose keels low and almost reaching anterior end of caudal peduncle base. Count of pores in cephalic sensory canal system as follows: 9 in supraorbital canal, 11–12 in infraorbital, 3 in occipital, 8–9 in mandibulo–opercular. Vertebral count 4+32–34.

Intestine with bend behind stomach ( Fig. 3). Air bladder fully enclosed in bony capsule.

Color pattern. In fresh specimens, general background of body cinerous ( Fig. 4 ). In formalin preserved specimens, general background of body yellowish brown. Irregular white spots scattered over dorsal and lateral aspects of body; sometimes predorsal region covered by irregular bars with narrow interspaces. Dorsal fin with dark blotch at base; dark spots more or less organized into 2 bands across branched rays. Blackish basal caudal bar indistinct and continuous, reaching dorsal and ventral midlines; caudal-fin with yellowish membranes between rays.

Sexual dimorphism. No sexual dimorphism was noted and males lack a suborbital flap.

Distribution. Known from the Leli-He(=River), a tributary of the You-Jiang (upper Pearl River drainage), Tianlin County, Guangxi Province, China ( Fig.5 ).

Etymology. The specific epithet is derived from the Latin albus (white) and guttata (spotted), in reference to the irregular white spots scattered over the dorsal and lateral regions of the body.

Figures

FIGURE 1. Schistura alboguttata, IHB2008050102, holotype, 65.9 mm SL, Leli-He, China.

FIGURE 2. Mouth in ventral view of Schistura alboguttata, IHB2008050102, holotype, 65.9 mm SL.

FIGURE 4. Live specimen of Schistura alboguttata, IHB2008050101, 71.4 mm SL, same collection data as holotype.

FIGURE 5. Distribution of Schistura alboguttata. Symbol indicates type locality.