Opsarius putaoensis, Qin & Maung & Chen, 2019

Qin, Tao, Maung, Kyaw Win & Chen, Xiao-Yong, 2019, Opsarius putaoensis, a new species of subfamily Danioninae (Actinopterygii, Cyprinidae) from the Irrawaddy River basin in northern Myanmar, Zootaxa 4615 (3), pp. 585-593 : 586-589

Opsarius putaoensis sp. nov.

(Figs. 1−3)

Holotype. KIZ QT20170033 , 89.9 mm SL, Putao Market near Airport, Kachin, Myanmar, T. Qin, SS. Shu and P. Zaw, 21 Nov. 2017.

Paratypes. SEABRI QT20170032, SEABRI 20171007, 69.4−89.5 mm SL, 2 ex., collected with the holotype; SEABRI 20151021, 43.2 mm SL, 1 ex., Putao Market , Kachin, Myanmar, XY. Chen, T. Qin, SS. Shu and Yunn Mi Mi Kyaw, 25 Dec. 2015 ; SEABRI 20140030, 58.9 mm SL, 1 ex., Putao Market, XY. Chen and T. Qin, 20 Nov. 2014; SEABRI 20171876−1884, 57.1−82.0 mm SL, 9 ex., Putao market, T. Qin, SS. Shu and P. Zaw, 19 Dec. 2017.

Diagnosis. Opsarius putaoensis is distinguished from its congeners in the subcontinent of India and Southeast Asia based on the following combination of characters: barbels absent (vs. present in most species with fewer than 11 branched anal-fin rays, except O. chatricensis , O. barna , and O. arunachalensis ); dentary with parallel rows of tubercles; snout much shorter than eye diameter; mouth gape below anterior edge of orbit; pectoral and pelvic axial scales lobate; lateral line completely perforated, with 35−38 scales; scale rows between dorsal-fin origin and lateral line 7−8; predorsal scales 15; circumpeduncular scales 12; branched dorsal-fin rays 7; branched anal-fin rays 9; branched pelvic-fin rays 7 (vs. 8 in most species except O. ngawa ); insertion of dorsal-fin not reaching pelvic-fin base (vs. reaching in O. chatricensis ); body with 6−7 vertical bars, extending to lateral line; and distal edge of dorsal fin black.

Description. Meristic and morphometric data listed in Table 1 .

Head short and compressed. Head length usually larger than head depth. Mouth terminal, upper jaw slightly longer in some individuals, mouth cleft just below level of midpoint of eye, mouth corner below anterior edge of orbit. One row of small horny tubercles on ventral side of dentary around midline present, 1−3 rows of large horny tubercles on lateral aspects of dentary, median densely arranged (Figure 2). Small tubercles present on snout tip and anterior lachrymal. Eyes large, situated in anterior and upper half of head. Interorbital space convex. Gill membrane not connected to isthmus. Barbels absent, even in juveniles.

Body compressed. Dorsum outline almost straight, descending after dorsal-fin origin. Abdomen rounded, more curved than dorsum. Dorsal-fin rays ii, 7 (14). Dorsal fin inserted posterior of posterior end of pelvic-fin base; distance between dorsal-fin origin and caudal-fin base almost equal to distance from dorsal-fin origin to middle to anterior orbit. Anal-fin rays ii, 9 (14). Anal-fin origin posterior of vertical through posterior of dorsal-fin base; analfin truncate, extending to around midpoint of caudal peduncle. Pectoral and pelvic fins with axillary lobes; soft, thin and long, about one third to one half length of pectoral and pelvic fins. Pectoral-fin rays i, 12 (14). Pectoral fin pointed, almost reaching pelvic-fin origin, reaching in some individuals; unbranched ray stiff. Pelvic-fin rays i, 7 (14). Pelvic-fin tip truncate, about one scale from anus. Anus just anterior to anal-fin origin. Caudal fin with 10+9 principal rays (14). Caudal fin deeply forked, tips pointed, lower lobe slightly longer than upper one. Lateral line complete, with 34−36+1−3 scales, total 35−38, mostly 37 (8) or 38 (4). Scale rows from dorsal-fin origin to lateral line 7 (3) or 8 (11); from lateral line to pelvic-fin origin 3 (14); from lateral line to anal-fin origin 3 (14). Predorsal scales 14 (3) or 15 (11). Circumpeduncular scales 12 (14).

Coloration. Six to seven black bars on lateral side of body and caudal peduncle; each bar about 3 scales wide. Anterior vertical bars on body long and reaching lateral line; 1−2 bars on caudal peduncle short, more like round blotch; 1 black cleithral blotch above gill opening present or absent. Small black spot on caudal-fin base present or absent. Distal edge of dorsal fin black; first, second, and fourth branched rays black, membrane hyaline, last unbranched ray black on lower half, upper half yellow. Anal fin hyaline, anterior and outer margins orange. Pectoral and pelvic fins hyaline. Caudal fin dark, posterior margin black.

Distribution. Rare, only known from Mali Hka River, near Putao, Kachin State, northern Myanmar (Figure 4). Other associated fish species recorded from the type locality include: Psilorhynchidae : Psilorhynchus brachyrhynchus ; Cyprinidae : Opsarius barnoides , Garra bispinosa , Placocheilus dulongensis ; Balitoridae : Homalopteroides rupicola ; Nemacheilidae : Schistura sikmaiensis , Schistura malaisei .

Etymology. The specific name derived from the type locality of the new species in Putao plain, adjectival.

Remarks. Opsarius putaoensis is further differentiated from congeners based on the following characters: lateral-line scales 35−38 (vs. 30−32 in O. profundus and O. bernatziki ; 32−36 in O. koratensis ; 36−42 in O. barna , O. barnoides , O. dogarsinghi , O. gatensis , O. infrafasciatus , O. nelsoni , O. ornatus , O. pulchellus , and O. signicaudus ; 42−45 in O. howesi , O. lairokensis , and O. ngawa ; 47 in O. bonarensis ; and 58−75 in O. tileo , O. dimorphicus , O. pectoralis , O. radiolatus , and O. shacra ); predorsal scales 15 (vs. 16−18 in O. ardens and O. bakeri ; 17−25 in O. barnoides , O. bendelisis , O. bonarensis , O. dogarsinghi , O. howesi , O. infrafasciatus , O. kanaensis , O. lairokensis , O. ngawa , O. ornatus , O. profundus , O. radiolatus , O. shacra , and O. signicaudus ; and 28−30 in O. tileo and O. pectoralis ); circumpeduncular scales 12 (vs. more than 14 in O. barnoides , O. chatricensis , O. howesi , and O. pulchellus ; and 16−17 in O. ngawa and O. dogarsinghi ); branched dorsal-fin rays 7 (vs. 8−9 in O. gatensis , O. lairokensis , and O. pulchellus ; and 10−11 in O. ardens , O. bakeri , O. canarensis and O. malabaricus ); branched anal-fin rays 9 (vs. 7−8 in O. arunachalensis , O. bendelisis , O. howesi , O. pectoralis , and O. shacra ; 10−11 in O. barna , O. barnoides , O. chatricensis , O. dimorphicus , O. koratensis , O. ngawa , O. lairokensis , O. ornatus , O. profundus , O. radiolatus , and O. tileo ; 11−12 in O. nelsoni and O. pulchellus ; and 12−15 in O. arden s, O. bakeri , O. canarensis , O. gatensis , and O. malabaricus ); body with 6−7 vertical bars (vs. 8−12 in O. barna , O. bendelisis , O. dogarsinghi , O. kanaensis , and O. shacra ; and 13−16 in O. barnoides , O. gatensis , O. howesi , O. lairokensis , and O. ngawa ); vertical bars extending to lateral line (not in O. barnoides , O. chatricensis , O. kanaensis , and O. lairokensis ); and edge of dorsal fin black (vs. hyaline in O. barnoides , O. howesi , O. infrafasciatus , O. lairokensis , O. ngawa , and O. signicaudus ).