Devario fangae, Kullander, Sven O., 2017

Kullander, Sven O., 2017, Devario fangae and Devario myitkyinae, two new species of danionin cyprinids from northern Myanmar (Teleostei: Cyprinidae: Danioninae), Zootaxa 4227 (3), pp. 407-421 : 409-412

Devario fangae , new species

( Figs. 1–3 )

Holotype. NRM 45659. Male, 47.9 mm SL; Myanmar, Kachin State, Putao, Ayeyarwaddy River drainage , Nan Hto Chaung, in Putao , ca. 1 mile from 46th regiment, close to rice mill, 27°19′44″N 97°22′36″E; 27 Mar 1998. S.O. Kullander & R. Britz (SOK-98-021A).

Paratypes. NRM 40918, 13, 43.0–61.0 mm SL; NRM 40919, 3, 36.5–55.7 mm SL; NRM 40930, 52, 10.9– 18.9 mm SL; NRM 41677, 1, ca. 20 mm SL; NRM 41678, 1, 23.5 mm SL; NRM 69442, 30, 29–58.7 mm SL; NRM 69443, 9, 21.0– 26.1 mm SL; NRM 69444, 15, 32.6–46.2 mm SL; NRM 69447, 10, 26.9–33.8 mm SL; Same data as holotype.—NRM 40942, 57, 11.9–25.4 mm SL; NRM 41274, 15, 12.6–18.3 mm SL; NRM 69439,11, 34.7– 51.3 mm SL; NRM 69440, 31, 29.1–50.0 mm SL; NRM 69441, 25 , 24.6–31.0 mm SL; Myanmar, Kachin State, Putao, Ayeyarwaddy River drainage, Ma Kyaww Wa Chaung and its tributary Nan Hto Chaung , in Putao , ca 1 mile from 46th regiment, approximately 27°19′44″N 97°22′36″E; 28 Mar 1998, S.O. Kullander & R. Britz (SOK-98- 021B).

Diagnosis. Devario fangae shares uniquely with D. browni and D. kakhienensis an anterior expansion in width of the P stripe. It differs from D. browni and D. kakhienensis in presence of a broad P stripe, wider than adjacent interstripes, vs. narrow, as wide as or narrower than interstripes. Devario fangae is further similar to species of Devario characterized by three dark stripes (P, P+1, P-1) along the side, but differs from these in having all three stripes wide and of similar width vs. P stripe wide and P+1 and P-1 stripes much narrower as in D. aequipinnatus , D. acrostomus , D. deruptotalea , D. fangfangae , D. fraseri , and D. gibber . In D. regina and D. malabaricus , the stripes are relatively wide but not wider than interspaces and the P stripe is split anteriorly by a short light interspace.

The status and diagnoses of D. assamensis (Barman, 1984) from the Brahmaputra River in southern Assam, and D. ostreographus (M’Clelland, 1839) , without locality, are uncertain, but both were described as extremely deep-bodied, and thus unlikely to be confused with D. fangae . From D. devario , D. fangae can be distinguished by presence vs. absence of infraorbital process and rostral barbel; distinct vs. very shallow danionine notch; 9½–11½ vs. 15½–17½ dorsal-fin rays; 30–32 vs. 42–47 lateral line scales; and 12 vs. 16 circumpeduncular scales.

From other species of Devario in Myanmar, D. fangae can be distinguished from nominal species D. affinis , D. annandalei , D. strigillifer , D. spinosus and D. yuensis by fewer scales in the lateral line (30–32, vs. 35–53); fewer circumpeduncular scales (12 vs. 14–20; and absence of a supraorbital process. It differs from D. xyrops in having a continuous P stripe vs. P stripe separated into two blotches. It differs from D. myitkyinae by the colour pattern, characterized by three dark, straight horizontal stripes on the middle of the side, vs. up to five irregular stripes; branched dorsal-fin rays 9½–10½, exceptionally 11½, vs. 11½–13½, exceptionally 10½; and branched anal-fin rays 9½–11½ vs. 12½–13½, exceptionally 11½ or 14½,

Devario fangae can be distinguished from all remaining species of Devario also by the striped colour pattern, vs. a pattern of large blotches as in D. kysonensis , D. pathirana , or smaller blotches as in D. quangbinhensis ; a very narrow posterior P stripe as in D. chrysotaeniatus , D. laoensis , D. leptos , D. micronema , D. neilgherriensis ; vertical bars as in D. apogon , D. apopyris , D. auropurpureus , D. interruptus , D. jayarami , D. maetaengensis , D. salmonatus , D. shanensis ; uniform, with or without a thin dark stripe posteriorly on the side as in D. acuticephala and D. sondhii ; P stripe separated into two blotches as in D. anomalus ; or wide P stripe posteriorly on side, but no other dark stripes as in D. naganensis . From barred devarios, D. fraseri , and D. malabaricus , D. fangae can be distinguished further by presence vs. absence of infraorbital process.

Description. Based on specimens in measurement series, with notes on variation. Largest female 61.0 mm SL, largest male 58.8 mm SL. Measurements are presented in Tables 1–2 . Counts for holotype are marked with an asterisk.

Body laterally compressed, elongate. Females deeper, prepelvic and preanal distances greater, than in males ( Fig. 3 , Table 2 ). Predorsal contour straight or slightly curved, ascending, with slight indentation marking position of lateralis canal of temporal commissure; sloping posteriorly from dorsal-fin insertion. Prepelvic contour curved, more so in females; chest compressed below pectoral fin, but not keeled. Snout short, rounded in dorsal aspect, subtriangular in lateral aspect, about as long as eye diameter in lateral aspect, relatively shorter in juveniles. Infraorbital process laminar, about twice as broad as high, with truncate or slightly concave distal margin. Danionine notch caudally margined by blunt anteromediad projecting laminar dentary process. Skin cover absent from distal part of infraorbital process, dentary process, and anterior margin of supraorbital. Mouth terminal, obliquely directed upwards. Small knob at dentary symphysis, fitting in depression in upper jaw. Maxilla reaching to below anterior margin of orbit. Jaws equal anteriorly; lower jaw ending anteriorly at horizontal through middle of eye, posteriorly at vertical through middle of eye. Lower jaw with large conical tubercles in band of 3–4 rows mediodorsally, band tapering to single row of tubercles symphysially and posteriorly. Males with strong, densely arranged sharp-tipped conical tubercles in narrow bands on anterior 5 branched rays of pectoral fin; smallest specimen with pectoral-fin tubercles 34.7 mm SL. Rostral barbel short, reaching slightly beyond base of maxillary barbel; maxillary barbel much shorter, less than half length of rostral barbel, not reaching below middle of orbit.

Lateral line complete, along 30 (8), 31* (7), 32 (5) scales, and 2 scales on caudal-fin base; comprising one tubed scale followed by a canal running steeply caudoventrad under about 5 unperforated scales to slightly posterior to pectoral-fin base, where curved caudad and represented by perforated scales running in a curve parallel to the ventral body outline and ending low on caudal peduncle and caudal-fin base; continued by two scales on caudal-fin base. Median predorsal scales 13 (8), 14* (12). Lateral scale rows passing between dorsal and pelvic fins ½7+1+2½* (20). Circumpeduncular scale rows 12* (20). A row of scales along anal-fin base. About ¼ of caudalfin length scaled basally.

Dorsal-fin rays iii.9 ½ (2), iii.10 ½* (16), iii.11 ½ (2). Anal-fin rays iii.9 ½ (1), iii.10 ½ (12), 11½* (7). Pectoralfin rays i.10 (3), i.11 * (8), i.12 (9). Pelvic-fin rays i.6 (1) i.7 * (19). Dorsal fin inserted at highest point of dorsum, little posterior to middle of body; distal margin straight, rays increasing in length to first branched ray, posterior rays gradually slightly shorter, last ray about 2/3 length of first branched ray, not reaching to middle of caudal peduncle. Anal fin inserted below anterior rays of dorsal fin; distal margin about straight, except last unbranched and first branched rays forming short extended tip; rays increasing in length to first branched ray, posterior rays gradually slightly shorter, last ray about half the length of first branched ray, reaching to middle of caudal peduncle. Pectoral-fin insertion at about vertical through posterior margin of osseous opercle; pectoral fin extending to pelvic-fin origin or, usually, slightly shorter. Pectoral-fin axial lobe well developed. Pelvic fin inserted slightly anterior to midbody, not reaching to anal-fin origin. Pelvic axillary scale present. Caudal fin forked, lobes of about equal length.

Vertebrae 16+15=31 (1), 16+16= 32 (2), 16+17=33 (1), 16+18=34* (1), 17+16=33 (6), 17+17=34 (9). Pharyngeal teeth 2,3,5/5,3,2 (NRM 40918, 48.8 mm SL).

Colouration in preservative. Dorsum pale grey or brown, sides pale yellowish white, abdomen white. Opercle pale brownish, grey or silvery depending on preservation. Sides of head sparsely pigmented. Narrow dark brown middorsal stripe from occiput to end of caudal peduncle. Dark brown or black, vertically extending cleithral spot covering part of first lateral-line scale and scale above. Dark brown or black broad P stripe, posteriorly one scale wide, anteriorly slightly widened to 1½ scale depth, from end of caudal peduncle rostrad to above pelvic-fin insertion (young, many adult females), or close to gill opening (most males, some adult females). P stripe bordered dorsally by narrow interstripe I. P+1 stripe brown or dark grey, parallel with P stripe, about one scale wide on middle, narrowing and fading on caudal peduncle and anteriorly on flank. P+1 stripe bordered dorsally by narrow interstripe I+2. No distinct P+2 stripe. Wide brown or dark grey P-1 stripe paralleling P stripe, tapering caudad and not reaching end of caual peduncle. Indistinct P-2 stripe in many specimens, fading separated from P-1 stripe by narrow indistinct I-1 interstripe. In specimens in which horizontal stripes not reaching head region dark pigment suffused over area anterior to P stripe, but no pattern formed. P stripe generally more contrasted in males than in females, and anterior terminal blotch variably developed. P stripe and cleithral spot present in juveniles 19 mm SL, adult pattern developing gradually ( Fig. 2 ). A few young specimens with aberrant colour pattern due to curvature and congruence of interstripes I and I+1, forming an oblong blotch ( Fig. 2 b), or fragmentation of interstripe I.

Dorsal and anal fins lightly pigmented, without markings; caudal fin basally lightly pigmented along middle rays, most of fin hyaline. Pectoral and pelvic fins hyaline.

Geographical distribution ( Fig. 3 ). Known only from small hillstreams near Putao, northern Myanmar. At the time of collecting in the low water season, the streams, in a setting of hilly low forests, were shallow, mostly less than 0.5 m deep, rarely more than 3 m wide, with clear water running over gravel, rocks or sand (Kullander, 2012: fig. 10). The velocity was relatively fast, including frequent riffles. Syntopic species included Amblyceps murraystuarti (Amblycipitidae) , Barilius barnoides , Danio flagrans , Garra sp., Pethia tiantian , Puntius compressus (Cyprinidae) , Badis pyema (Badidae) , Batasio procerus (Bagridae) , Heteropneustes fossilis (Clariidae) , Mastacembelus armatus (Mastacembelidae) , Acanthocobitis sp., Schistura sp. ( Nemacheilidae ), and Psilorhynchus brachyrhynchus (Psilorhynchidae) . A single specimen of Devario aequipinnatus was reported by Chaudhuri (1919) from Putao. Based on Chaudhuri’s short description it probably represents D. fangae .

Etymology. This species was singled out by the late Fang Fang (1962–2010) for description as new, including separation of the holotype, and it seems pertinent to attach her name to it as the proper discoverer, and also recognizing her deep personal interest in the freshwater fishes of Myanmar. A noun in the genitive case.

Figures

FIGURE 1. Devario fangae. (a) holotype, NRM 45659, male, 47.9 mm SL; (b) paratype, NRM 40919, male 58.5 mm SL; c) paratype, NRM 69442, female, 49.2 mm SL. All from Kachin State, Putao, Ayeyarwaddy River drainage, Nan Hto Chaung.

FIGURE 2. Devario fangae. (a) paratype NRM 69440, 30.0 mm SL; (b) paratype, NRM 69442, 43.4 mm SL. Both from Kachin State, Putao, Ayeyarwaddy River drainage, Nan Hto Chaung.

FIGURE 3. Devario fangae. Plot of body depth on standard length by sex, based on sample from out of NRM 40918 – 40919, 45659, 69440, 69442, 10 males, 10 females. Regression lines are significantly different (ANCOVA, p = 0).