Altigena laticeps ( Wu & Lin 1977 )

Ciccotto, Patrick J., Lin, Feng & Chen, Xiao-Yong, 2021, Taxonomic revisions of Altigena laticeps and A. lippa (Cyprinidae: Labeoninae) from the Mekong River Basin, Zootaxa 4941 (2), pp. 271-280 : 272-273

Altigena laticeps ( Wu & Lin 1977)

Figures 1–2

Sinilabeo tonkinensis laticeps Wu & Lin in Wu, Lin, Chen, Chen & He 1977

Sinilabeo laticeps— Chu & Cui in Chu & Chen 1989

Diagnosis. A member of Altigena based on characters listed by Kottelat (2017). Altigena laticeps can be distinguished from all species in the genus by the following combination of characters: 14–16 predorsal scales; 40–42 lateral-line scales; and 20 circumpeduncular scales.

Description. Morphometrics of type and non-type material presented in Table 1. Mouth inferior, strongly arched. Rostral cap thick, pendulous; crenulated medially, smooth laterally in smaller specimens, uniformly smooth in larger specimens, separated from upper lip by deep groove, covering all but edge of upper lip. Upper lip entirely enclosing upper jaw, edge smooth, continuous with labial fold at corners of mouth. Labial fold thin and papillose, separate from lower jaw by deep grove, margined posteriorly by plical groove. Pair of gular grooves present, connected with plical groove. Maxillary barbels, if present small. Three rows of tubercles on tip of snout, sublachrymal grooves on sides of rostral cap partially divide anteriormost row from posterior rows. Shallow ethmoidal furrow present, separating 3 rows of tubercles on snout from row or patch of small tubercles between nares.

Dorsal profile slightly arched, deepest at dorsal-fin insertion. Ventral profile flat to slightly concave. Head short, longer than wide; snout conical, rounded or triangular when viewed from dorsal side; eyes dorsolateral. Dorsal-fin origin anterior of pelvic-fin origin. Pectoral fins positioned ventrally, reaching approximately 2/3 from origin to pelvic-fin origin. Pelvic fins reaching ¾ to anal fin. Anal fin just reaching insertion of caudal-fin when adpressed. Dorsal and anal fins concave to falcate; pectoral and pelvic fins triangular. Caudal fin forked. Axillary pelvic lobes well-developed.

Dorsal fin with 3 simple and 10½ branched rays; anal fin with 3 simple and 5½ branched rays; pelvic fin with 1 simple 8 branched rays; pectoral fin with 1 simple and 14 branched rays; caudal fin with 10+9 principal rays, 9+8 branched. Body entirely scaled except for predorsal midline; scales on chest smaller and more embedded than remainder of body. Lateral-line scales and pored scales on caudal fin 40–42; predorsal scales 14–16; scale rows between dorsal-fin insertion and lateral line 5–5½; scale rows between anal-fin insertion and lateral line 4–4½; scale rows between pelvic-fin origin and lateral line 4½; 20 circumpeduncular scales.

In preservative ( Fig. 1 ), specimens brown, generally lighter on venter; dark brown vertically elongate blotch present at base of caudal peduncle. Fins clear except for tiny melanophores on interradial membranes of dorsal and caudal fin. In life, ( Fig. 2 ), body olive green with pink to red spots in center of scales along flank and caudal peduncle, spots on anterior ½ of flank larger than those on posterior ½; venter white; blotch at base of caudal peduncle with blue-green iridescence. Fins orange to red, ventral fins with white leading edges.

Distribution. Altigena laticeps is distributed in the Upper Mekong River basin in Xishuangbanna of the Yunnan Province of China ( Fig. 3 ).

Material Examined. China: IHB 634069 , 1 (syntype), 196.0 mm SL, Yunnan Province, Mengla County, Bu- Yuen Jiang , 21.92141N, 101.27921E ; IHB 8810217 , 1 , 88.6 mm SL, Yunnan Province, Xishuangbanna, Menglun , 21.9383N, 101.252E ; KIZ 1981001234 , 1, 155.9 mm SL, same as IHB 8810217 ; KIZ 197800799 , 1, 135.3 mm SL, same as IHB 8810217 ; KIZ 2008077 , 1, 237.9 mm SL, Yunnan Province, Xishuangbanna, Daluo , 22.08829N, 101.0248E ; KIZ 2008078 , 1, 189.9 mm SL, same as IHB 8810217 .

Figures

FIGURE 1. KIZ 1981001234, Altigena laticeps, 155.9 mm SL.

FIGURE 2. Altigena laticeps, KIZ uncatalogued, 214 mm SL, from Manpa Village, Xiang Ming Township, Menla County, Xishuangbanna, Yunnan. Photograph by T. Qin (KIZ).

FIGURE 3. Distributions of georeferenced specimens examined of Altigena laticeps and A. lippa. Map by D. Boyd (FLMNH).