Altigena malihkaia, a new species of Labeonini (Teleostei: Cyprinidae) from the Irrawaddy River basin in Myanmar Author Zheng, Lan-Ping Author Qin, Tao Author Chen, Xiao-Yong text Zootaxa 2018 2018-09-13 4476 1 87 93 journal article 29434 10.11646/zootaxa.4476.1.8 57639aad-66a2-4235-8d6f-86db8f713b38 1175-5326 1440456 23AFF101-7EC9-4478-B016-E9C18E4247E9 Altigena malihkaia sp. nov. ( Figs. 1–4 ) Holotype . SEABRI 2016000004, 122.7 mm SL; Putao market, Kachin State, Myanmar , August , 2016. Paratypes . KIZ 20140063, 096–097, 3 ex. 74.6–98.6 mm SL, Putao market, Kachin State, Myanmar , December, 2014; SEABRI 2015000001–007, KIZ 20150263–264, KIZ 2015005389, 10 ex., 92.0– 167.5 mm SL, Putao market, Kachin State, Myanmar , December, 2015; SEABRI 2016000001-003, KIZ 20160294, 4 ex. 89.2– 162.0 mm SL, Putao market, Kachin State, Myanmar , August, 2016. Non-types. SEABRI 20170184–185, 2 ex., 72.6–144.9 mm SL; Mali Hka River, a tributary of Irrawaddy River, 27°38'51"N 97°22'34"E , Kachin State, Myanmar , 6 December 2017 . Diagnosis. Altigena malihkaia sp. nov. is distinguished from all other genera of Labeonini by the combination of a thick, pendulous rostral fold, upper lip closely adnate to upper jaw, upper and lower lips continuous around corner of mouth, continuous postlabial groove, pair of mental grooves, one pair of maxillary barbels, and 10–11 branched dorsal-fin rays. It differs from the congeneric species by having 12–14 circumpeduncular scales, 17–20 pre-dorsal midline scales, wide head (96.8–138.5% HL), longer postorbital length (64.6–81.0% HL), and short dorsal fin (21.9–26.2% SL). TABLE 1. Morphometric data for type specimens of Altigena malihkaia sp. nov.

n=18	17 paratypes and the holotype
Characters	Holotype	Range	Mean	SD
Standard length (mm)	107.6	74.6–167.5	-	-
Total length (mm)	136.4	95.1–223.2	-	-
Percentage of SL
Body depth	24.1	20.1–24.5	22.4	1.36
Head length	23.0	18.9–23.0	20.5	1.10
Head depth	15.6	13.6–16.4	15.1	0.78
Head width	14.3	13.9–17.2	15.3	0.91
Dorsal-fin length	26.2	21.9–26.2	24.1	1.17
Pectoral-fin length	21.4	17.8–22.7	20.6	1.25
Pelvic-fin length	17.7	16.8–21.6	18.8	1.20
Anal-fin length	21.5	18.9–21.7	20.2	0.95
Caudal-peduncle length	16.3	16.3–21.8	18.2	1.26
Caudal-peduncle depth	15.1	11.8–15.2	13.5	0.82
Predorsal length	43.7	43.6–49.4	46.1	1.81
Prepectoral length	22.1	19.6–22.1	20.9	0.85
Prepelvic length	54.9	48.8–55.2	52.6	2.02
Preanal length	76.4	68.3–77.7	72.5	2.99
Percentage of HL
Snout length	43.8	41.9–55.5	47.7	3.87
Head depth	67.6	67.4–80.0	73.7	3.88
Eye diameter	19.7	18.8–26.4	22.0	2.19
Interorbital width	39.4	39.4–56.3	48.5	4.12
Head width	103.3	96.8–138.5	112.2	9.31
Postorbital length	66.9	64.6–81.0	72.4	4.38

Description. Morphometric data are listed in Table 1 . Body rounded and caudal peduncle compressed, abdomen smooth. Deepest part of body usually in front of dorsal-fin origin. Head rounded, depth smaller than width. Snout moderately rounded, length longer than postorbital length. Small distinct keratinized tubercles densely set on tip of snout. Eye moderately large, diameter 18.8–26.4% HL, in posterior half of head, close to dorsal profile. Largest specimen 167.5 mm SL; 45 vertebrae (KIZ 2015005389, n=1) ( Fig. 3 ). FIGURE 1. Lateral view of Altigena malihkaia sp. nov. , paratype, SEABRI 2016000003, 154.4 mm SL. FIGURE 2. Oromandibular structures of Altigena : (A) A. malihkaia sp. nov. , SEABRI 2016000003, 154.4 mm SL; (B) A. tonkinensis , KIZ 200401163, 135.4 mm SL; (C) A. wui , KIZ 776521, 188.6 mm SL; (D) A. yunnanensis , KIZ 20160172, 368.3 mm SL. rf = rostral fold; ul = upper lip; lj = lower jaw; ll = lower lip; mg = mental groove; pg = postlabial groove. Mouth inferior ( Fig. 2 ). Rostral fold thick, pendulous, shallowly crenulated medially, smooth laterally, edge of upper lip exposed. Upper lip closely adnate to upper jaw and easily overlooked, except at lateral-most extremities. Upper and lower lips continuous around corner of mouth. Edge of lower jaw keratinized, blunt and crescentic, conspicuously exposed, separated from lower lip by deep groove. Lower lip with band of papillae along anterior edge. Posterior groove deep and continuous. Pair of mental grooves present on lower lip, connected with postlabial grooves. Pair of very short maxillary barbels. Maxillary barbels slender, weak, shorter than eye diameter, at corner of mouth. Three rows of pharyngeal teeth: 5.4.2 (KIZ 20150264, n=1) or 5.3.3 (KIZ 20150263, n=1). FIGURE 3. Radiograph of Altigena malihkaia sp. nov. , KIZ 2015005389, paratype, 107.6 mm SL. FIGURE 4. Altigena malihkaia sp. nov. , alive, SEABRI 20170184, 144.9 mm SL. Dorsal fin with 3 soft unbranched rays and 10–11 branched rays, origin nearer tip of snout than caudal-fin base, margin concave. Anal fin with 3 unbranched and 5 branched rays, margin concave, tip exceeding halfway between anal-fin and caudal-fin bases, but not reaching caudal-fin base. Pectoral fin with 12–14 branched rays, exceeding halfway between pectoral-fin and pelvic-fin origins. Pelvic-fin with 8–9 branched rays, origin posterior to dorsalfin origin, tip exceeding halfway between pelvic-fin and anal-fin origins, not reaching anal-fin origin in large individuals, reaching in specimens less than 93 mm SL. Axillary pelvic lobe present. Anus closer to anal-fin origin than to posterior endpoint of pelvic-fin base. Distance from anus to anal-fin nearly equal to eye diameter. Caudal fin with 9 upper + 8 lower branched rays, forked, upper lobe slightly shorter than lower lobe. Scales large, scales of abdomen embedded under skin. Pre-dorsal midline scales 17–20, smaller than flank scales, somewhat irregular, not embedded under skin. Lateral line complete and straight, ending at caudal-fin base; 45–49 lateral-line scales; 5–6 scale rows between lateral line and origin of dorsal-fin; 4–5 scale rows between lateral line and origin of pelvic-fin; 12–14 circumpeduncular scales. Colouration. In preserved specimens, body dark brown dorsally, light brown ventrally. Black blotch on flank above pectoral fin and on caudal-fin base, their width equal to 3 scales. Fin-rays black, membranes hyaline. Body of live olive green, with light purple sheen on scales, paired fins orange ( Fig. 4 ). Distribution and ecology. Altigena malihkaia is known only from the upper reach of Mali Hka River, a tributary of Irrawaddy River in Myanmar ( Fig. 5 ). This species occurs in the sluggish zone of the main stream at an altitude of 539 meters, particularly in areas about 2–3 meters deep. The substrate of the river consists of boulders, cobble and sand ( Fig. 6 ). Syntopic species include Devario fangae , Tor qiaojiensis , Neolissochilus compressus , Garra salweenica , and Pterocryptis berdmorei . Etymology. Named for the type locality, the Mali Hka River. To be treated as a noun in apposition.