Sinocrossocheilus guizhouensis Wu

Yuan, Le-Yang, Zhang, E & Huang, Yan-Fei, 2008, Revision of the Labeonine Genus Sinocrossocheilus (Teleostei: Cyprinidae) from South China, Zootaxa 1809, pp. 36-48 : 39-42

Sinocrossocheilus guizhouensis Wu in Wu, Lin, Chen, Chen & He, 1977

Figs. 2 A and 3A

Sinocrossocheilus guizhouensis Wu in Wu, Lin, Chen, Chen & He, 1977: 359 (Wu Jiang in Zunyi City, Guizhou); Zhang et al., 2000: 234 (Wu Jiang in Zunyi, Guizhou).

Material examined. IHB 6650409–11, 6650415–20, 6650503–6, 6650508, 6650510, syntypes, 15 ex., 53.6– 77.1 mm SL; South China, Guizhou Province, upper Yangtze River drainage: Wu Jiang at Zunyi City (approximately 27º42’N, 106º54’E).

Diagnosis. A species of Sinocrossocheilus having a lower lip with a greatly protruded crescentic fold; no longitudinal black stripe running along lateral line on flank; black blotches on intermediate interradial membranes between dorsal-fin rays; a submarginal stripe running along each lobe of caudal fin; a deep body (depth 20.1–24.2 [mean 22.8, SD 1.3] % SL); and a long snout (length 50.4–57.8 [mean 52.8, SD 2.2] % of HL).

Description. Morphometric data for 15 type specimens are presented in Table 1. See Figure 2 A for the morphology of the oromandibular structures and Figure 3 A for general body appearance.

Body elongate, slightly compressed, more so toward caudal-fin base, with greatest body depth immediately anterior to dorsal-fin origin and least caudal peduncle depth closer to caudal-fin base than to posterior end of anal-fin base. Dorsal head profile somewhat convex; ventral head profile straight. Dorsal body profile straight anterior to dorsal-fin origin; slightly concave from dorsal fin origin to origin of dorsal procurrent caudal-fin rays. Ventral body profile rounded anterior to anal-fin origin; slightly concave from anal-fin origin to origin of ventral procurrent caudal-fin rays.

Head relatively small, longer than width and wider than depth. Eyes small, dorsolaterally positioned in posterior half of head; interorbital space wide, slightly convex. Snout blunt when viewed dorsally, with many tubercles on tip of snout and anterior part of lachrymal. Tubercles small, conical with blunt tips, irregularly organized in two rows. Lateral portion of snout with a shallow, oblique furrow running from base of rostral barbel to lateral extremity of rostral fold along anteroventral border of lachrymal. Barbel lengths nearly equal to eye diameter; rostral barbel located in anterior end of shallow furrow on side of snout, and maxillary barbel rooted in corner of mouth, or between lateral extremity of rostral fold and lateral lobe of lower lip. Mouth slightly arch-shaped.

Rostral fold coarsely crenulated, covered densely with papillae, disconnected from lower lip at corners of mouth or ending next to maxillary barbel base. No upper lip or vestigial, with many minute papillae or lobes arranged in a longitudinal row on upper jaw. Upper jaw bearing a thick, flexible, cornified sheath entirely covered by pendulous rostral fold, and discontinuous from lower lip at corners of mouth. Median lobe of lower lip large; anterior and anterolateral edges modified to from a densely papillated, greatly protruded, crescentic fold anteriorly separated from lower jaw by a deep, arched groove and posteriorly bordered with a triangular fleshy pad in a shallow, arched groove; fleshy pad almost triangular, slightly protruded, densely papillated. Lower jaw bearing a thick, cornified cutting edge.

Dorsal fin with 3 simple and 7 (15) branched rays, last one split to base; origin closer to snout tip than to caudal-fin base; last simple ray shorter than HL; distal margin slightly concave. Pectoral fin with 1 simple and 14 (7) or 15 (8) branched rays, slightly longer than HL; tip of depressed fin extending slightly beyond halfway to pelvic-fin origin. Pelvic fin with 1 simple and 8 (15) branched rays, slightly shorter than HL; origin posterior to vertical of second or third dorsal-fin ray; tip of depressed fin not extending to anus but beyond halfway to anal-fin origin; pelvic axillary scale long, reaching beyond base of last ray. Anal fin with 3 simple and 5 (15) branched rays, last one spilt to base; origin in midway between pelvic-fin insertion and caudal-fin base; distal margin slightly concave. Anus anterior to anal-fin origin, separated from it by 3 scales. Caudal deeply forked, upper and lower lobes equal in shape and length.

Scales moderately large; lateral line complete, horizontal, 38 (6), 39 (7) or 40 (2) plus 3 scales on caudalfin base; predorsal midline scales irregularly arranged, smaller than those on flank; 5 1/2 / 1 /4 1/2 (15) scales in transverse row anterior to pelvic fin; circumpeduncular scales 14 (15). Chest and belly scaled, scales along mid-ventral region smaller than those on flank, embedded beneath skin. Gas bladder bipartite, anterior chamber round and posterior chamber slender, twice as long as anterior one. Pharyngeal teeth biserial, tooth pattern 3,5–5,3 (3), with compressed and pointed tips. Gill rakers sparse, short and small.

Colour pattern in alcohol. Body brownish dorsally, and pale yellow ventrally. A distinct black bar on upper half of flank immediately above fifth lateral line scale. Dorsal fin with black blotches on intermediate interradial membranes between rays; caudal fin with a black submargin stripe along lobe; all other fins yellowish.

Distribution. Sinocrossocheilus guizhouensis is known only from the Wu Jiang of the upper Yangtze River drainage at Zunyi County, Guizhou Province ( Fig. 4 ).

Remarks. The original description of S. guizhouensis by Wu in Wu et al. (1977) was based on 15 syntypes from the Wu Jiang of the upper Yangtze River drainage in Guizhou Province, South China. To preserve stability of nomenclature, a specimen (IHB 6650508, 59.0 mm SL) from the syntypes is here designated as the lectotype of S. guizhouensis to be the unique bearer of the name. The other syntypes therefore automatically become paralectotypes.

Sinocrossocheilus guizhouensis is distinguished from a single congener, S. labiatus , in having a lower lip with a greatly protruded (vs. flattened) crescentic fold; no longitudinal black stripe along the lateral line on the flank (vs. present); black blotches on intermediate interradial membranes between dorsal-fin rays (vs. absent); a submargin stripe along each lobe of the caudal fin (vs. absent); a deeper body (depth 20.1–24.2 [mean 22.8, SD 1.3] % SL vs. 17.4 –22.6 [mean 18.9, SD 2.0]; Fig. 5 ); and a longer snout (length 50.4–57.8 [mean 52.8, SD 2.2] % of HL vs. 42.2–49.0 [mean 45.6, SD 2.5]).

Li in Wu (1989) recognized, as S. guizhouensis , material from the Dagou He, a tributary flowing to the Liu Jiang of the Pearl River drainage, at Libo County, Guizhou Province, South China. In his description and figure, the material has no conspicuous black bar on the upper half of the flank immediately above the fifth lateral line scale, eight branched dorsal-fin rays, 15–18 gill rakers, and 16 circumpeduncular scales. All these characters disagree with the original description of either S. guizhouensis or S. microstomatus (here referred to Hongshuia , see the discussion section), a species presently known from the same locality as Lin in Wu’s material. However, the description of the lower lip morphology given by Li in Wu (1989) is vague, and does not clearly indicate that the material belongs in Hongshuia or Sinocrossocheilus . Given that Sinocrossocheilus here defined is known only from the upper Yangtze River drainage, it is highly likely that this material belong in Hongshuia . Without access to Lin in Wu’s material in this study, we leave its taxonomic status to be

Figures

FIGURE 2. Ventral view of lower lip morphology in: (A) Sinocrossocheilus guizhouensis, IHB 6650508, lectotype, 59.0 mm SL; (B) Sinocrossocheilus labiatus; KIZ 995338, holotype, 56.1 mm SL; (C) Hongshuia paoli, IHB 200210911, holotype, 54.3 mm SL; (D) Hongshuia microstomatus, IHB 87 IV 506, paratype, 81.7 mm SL; (E) Pseudocrossocheilus bamaensis, IHB 85 VII 056, 152.9 mm SL; (F) Pseudocrossocheilus tridentis, KIZ 774079, holotype, 118.0 mm SL. cf = crescentic fold of median lobe of lower lip; fp = fleshy pad of median lobe of lower lip; mb = median lobe of lower lip; rlf = ring-like fold of median lobe of lower lip.

FIGURE 3. Lateral view of: (A) Sinocrossocheilus guizhouensis, IHB 6650508, lectotype, 59.0 mm SL; (B) Sinocrossocheilus labiatus; KIZ 995338, holotype, 56.1 mm SL; (C) Hongshuia paoli, IHB 200210911, holotype, 54.3 mm SL.

FIGURE 4. Map showing distributions of two species of Sinocrossocheilus in South China.

FIGURE 5. Body depth plotted against SL, showing the difference in the body depth between two species of Sinocrossocheilus: S. guizhouensis () and S. labiatus ()