Sinigarra napoense, Zhang, E & Zhou, Wei, 2012

Zhang, E & Zhou, Wei, 2012, Sinigarra napoense, a new genus and species of labeonin fishes (Teleostei: Cyprinidae) from Guangxi Province, South China, Zootaxa 3586, pp. 17-25 : 19-21

Sinigarra napoense , new species

Figures 2 , 3 ; Table 1

Holotype. IHB 201001008, 87.3 mm SL, a tributary flowing into Zuo-Jiang of Zhu-Jiang (Pearl River) drainage at Napo County, Guangxi, South China; coll. Yu Zhu, July, 2010.

Paratypes. IHB 201001010–11, 201001015–6, 201001018–22, 9 specimens, 46.8–84.6 mm SL, same data as holotype.

Diagnosis. See generic diagnosis.

Description. Morphometric data for ten type specimens are given in Table 1. Body elongate, slightly compressed, more so towards caudal-fin base, with greatest depth at dorsal-fin origin and least depth of caudal peduncle slightly closer to caudal-fin base than to posterior end of anal-fin base ( Fig. 2 ). Dorsal profile of head slightly convex, with a small hump immediately posterior to head. Profile of predorsal body straight or slightly convex; from dorsal-fin origin to origin of dorsal procurrent caudal-fin rays profile somewhat concave. Ventral profile from snout tip to anal-fin origin rounded; from there to origin of ventral procurrent caudal-fin rays nearly straight.

Head relatively small, longer than wide. Eyes small with a wide, slightly convex interorbital space, dorsolaterally positioned in middle of head. Snout blunt in lateral view and pointed in dorsal view, with a shallow groove running along anteroventral border of lachrymal from rostral-barbel base to lateral extremity of rostral cap; no tubercle on its tip and anterior portion of lachrymal. Two pairs of tiny barbels; rostral barbel placed at anterior end of shallow sublachrymal groove on each side of snout and extending far away from anterior edge of eye; maxillary barbel rooted in corners of mouth, originating from exterior surface of confluence between anterolateral lobe of lower lip and lateral extremity of rostral cap, extending slightly beyond anterior edge of eye to opercle. Mouth inferior.

TABLE 1. Morphometric data for type specimens of Sinigarra napoense . Paratypes (9)

Rostral cap slightly crenulated in median part of its distal margin, and laterally connected with lower lip around corners of mouth. Upper lip present, but separated from upper jaw, laterally connected by a frenum with rostral cap and lower lip. Upper jaw with a thick flexible horny sheath on its margin, and laterally discontinuous from lower lip at corner of mouth ( Fig. 3 ). Lower lip modified into a mental adhesive disc posteriorly discontinuous with mental region; mental adhesive disc composed of an anteromedian callous pad, two anterolateral lobes and two lateroposterior lobes. Anteromedian callous pad large, coarsely inverted-triangular, anteriorly separated from lower jaw by a transverse groove, lateroposteriorly bordered in an oblique groove with lateroposterior lobe, and posteromedially confluent with lateroposterior lobe. Anterior edge of anteromedian callous pad slightly protruded, but not forming a distinctive anteromedian fold and central part slightly protruded; no clearly delineated boundary between them. Anterolateral lobe small, irregularly furrowed, and placed between maxillary barbel and anteromedian callous pad. Lateroposterior lobe elongate, with its anterior end confluent with anterolateral lobe and its posterior end anteriorly confluent with anteromedian callus pad and posteriorly free, separated from its counterpart by a median interruption that slightly intrudes into the anteromedian callous pad. Indistinct papillae sparsely scattered over ventral margin of rostral cap and lower lip. Lower jaw bearing a thick, flexible, horny sheath on its distal margin.

Dorsal-fin with four simple and 8* (10) branched rays, last one split to base; origin slightly nearer to tip of snout than to caudal-fin base; last unbranched ray slightly shorter than HL; distal margin concave. Pectoral fin falcate, with one unbranched and 11* (6) or 12 (4) branched rays, inserted posterior to vertical through posteriormost point of opercle, extending beyond halfway to pelvic-fin insertion and as far as fourth or fifth scale anterior to pelvic-fin insertion. Pelvic fin with one unbranched and 8* (10) branched rays, inserted vertically posterior to first branched dorsal-fin ray base, but not extending to vent. Anal fin with three unbranched and 5*(10) branched rays, last one split to base; distal margin slightly concave or straight; origin closer to pelvic-fin insertion than to caudalfin base. Caudal deeply forked; upper and lower lobes equal in length and shape.

Body scales moderately sized; chest and belly scaled, scales smaller than ones on flank, especially those on nearby mid-ventral region, embedded beneath skin. Lateral line complete, horizontal, with 38*(1), 40 (7) or 41(2) plus three scales on caudal-fin base; scale rows above lateral line 5* (10) and below 3 (5) or 4* (5). Predorsal scales 13 (2), 14*(4) or 15 (4), smaller than those on flank. Circumpeduncular scale rows 14 (4) or 16*(6). Axillary scale present at pelvic-fin base, extending slightly beyond base of last ray. Anus apart from anal-fin origin by two scales. Pharyngeal teeth triserial; tooth pattern 2, 3, 5–5, 3, 2 (1), with pointed and compressed tips. Gas bladder bipartite; anterior chamber oval, wider than posterior one; posterior one stick-like or elongate with an enlarged, rounded distal end, about twice as long as anterior one. Intestine long, forming many coils. Gill rakes on outer side of first gill arch, sparse, short and small.

Color pattern in formalin. Top of head, snout, cheek, opercle and subopercle brownish. Ventral surface of head yellowish-white. Ground color of body brownish dorsally and laterally, yellowish-white ventrally. Each scale on flank with dark chromatophores along exposed portion of its posterior margin forming a dark, crescentic, vertically-elongate mark; marks on scales above lateral line more prominent. Black mark on dorsal-fin base. Dorsal and caudal fins with dark chromatophores on fin rays, giving them a dusky appearance. Pectoral fins with dark chromatophores on anterior fin rays, giving them a dusky appearance. Pelvic and anal fins hyaline.

Distribution. Known only from a tributary of the Zuo Jiang of the Zhu Jiang drainage at Napo County, Guangxi Province, South China (Fig. 4).

Etymology. The specific epithet, used as adjective, is based on the type locality Napo County.

Figures

FIGURE 2. Lateral view of Sinigarra napoense, IHB 201001008, holotype.

FIGURE 3. Ventral view of oromandibular structures in Sinigarra napoense, IHB 201001008, holotype.