Description. General appearance shown in Fig. 2 A. Morphometric and meristic data given in Table 1. Dorsohypural distance equal to distance from dorsal-fin origin to area between vertical through anterior margin and posterior margin of eye. Limit between head and trunk indistinct in lateral view. Cephalic tubercles absent. Lateral line complete (all scales perforated; 24 – 26 + 3 – 5). Dorsal-fin origin over 13 th lateral-line scale. Tip of adpressed pectoral fin barely reaching vertical through pelvic-fin insertion. Pelvic fin inserted below 12 th lateral-line scale and distinctly anterior to vertical through dorsal-fin origin. Tip of adpressed pelvic fin extending past anal opening almost to anal-fin origin; in larger specimens reaching anal-fin origin. Anal-fin origin below 18 th or 19 th lateralline scale. Coloration in alcohol. General body coloration in alcohol preservation shown in Fig. 2 A. Schematic lateral body pigmentation shown in Fig. 7 A. Lachrymal region superficially pigmented with scattered small melanophores more concentrated peripherally. Dusky gular pigmentation reaching posteriorly to vertical through rictus. Occipital region with two superficial lines and one deeply-embedded solid line in between. Post-opercular streak thick and prominent with dense melanophores; situated posterior to and running along pectoral girdle and reaching ventrally to axillary lobe of pectoral fin. Axillary lobe pigmented with more sparsely-distributed and stellate melanophores as far as subdistal portion. Mid-dorsal stripe one-fourth scale wide and extending from nape to dorsal part of caudal peduncle. Rasbora arundinata Rasbora haru n = 31 n = 25 Range Mean ± SD Range Mean ± SD Standard length (mm) 42.7 – 86.3 68.8 ± 14.2 26.5 – 80.3 56.7 ± 13.8 Percentage of standard length Total length 135.0 – 142.7 139.2 ± 1.7 136.6 – 144.3 140.0 ± 1.7 Peripheral reticulation distinct and covering at maximum four longitudinal scale rows along dorsolateral portion of body. Basal reticulation distinct and covering up to five longitudinal scale rows and also dorsal scale row, with network of independent chevron-shaped bars. Peripheral and basal reticulation overlapping on first to fourth longitudinal scale rows and also on dorsal scale row. Black midlateral stripe prominent, more intense on central portion forming somewhat wedge-shaped subdorsal blotch, and overall forming reed-leaf-like profile. Stripe slightly angled anteroventrally and strongly tapering anteriorly until becoming obscure thin line reaching mid-humeral region. Stripe slightly attenuating posteriorly with ventral margin slightly ascending and extending to black basicaudal blotch. Axial streak posteriorly overlapping dorsal margin of black midlateral stripe, but streak separate from stripe in area above 12 th or 13 th lateral-line scale. Streak decreasing in intensity anteriorly until diffusing above 7 th lateral-line scale. Longitudinal light area indistinct, most visible along area adjacent to posterodorsal portion of axial streak and black midlateral stripe, but covered with reticulation. Deeply-embedded diamond-shaped black basicaudal blotch confluent anteromedially with black midlateral stripe. Blotch consisting two elements: basicaudal triangular patch and basicaudal spot. Basicaudal triangular patch confluent anteriorly with black midlateral stripe, originating posterior to hypural notch, and flaring posteriorly. In some specimens, triangular expansion not well-developed. Basicaudal spot confluent anteriorly with and appearing darker than triangular patch, and terminating anterior to medial sheath scale of caudal fin. Supranal pigmentation distinct appearing as a somewhat tear-shaped black patch smaller than pupil, originating slightly posterior to vertical through anal-fin origin, and terminating at vertical through base of third branched anal-fin ray. Subpeduncular pigmentation dusky, slightly decreasing in intensity anteriorly. Distal edge of caudal fin pigmented with scattered melanophores resulting in narrow dusky striped margin. Coloration in life. Ground coloration of dorsolateral surface of head and body pale brown with slightly silvery sheen, ventral surface barely pigmented with whitish reflective guanine (Fig. 4 A – C). Dorsum of head largely dusky, with scattered yellowish reflective patches and streaks on snout, lateral-line canals, meningeal layer, and supraorbital. Anterodorsomedial portions of operculum and upper end of gill slit with reflective yellowish patches (Fig. 4 C). Reflective midlateral stripe metallic yellowish, juxtaposed ventrally by black midlateral stripe. Reflective stripe prominent on anterior portion of trunk, continuously extending from humeral region, slightly widening posteriorly until above 9 th or 10 th lateral-line scale, then tapering posteriorly until appearing as thin reflective line below dorsal fin, and terminating at hypural notch (Fig. 4 A – B). Black peripheral reticulation bordered anteriorly by metallic yellowish sheen overall appearing as reticulated pattern of yellowish reflective crescents. All fins hyaline. Dorsal and caudal fins with yellowish sheen on subdistal portion of branched rays. Habitat and distribution. The specimens of Rasbora arundinata were collected in various types of habitat, such as gravel-bottomed mountain streams, moderate-flowing turbid rivers, and muddy backwater pools. This species is known from the Tripa Jaya, Kluet, and Alas rivers that flow into the Indian Ocean in the southern part of northwestern Sumatra (Fig. 8). Rasbora arundinata was collected sympatrically with Rasbora api, R. kluetensis (only in the Kluet River), R. jacobsoni, and R. truncata (only in the Alas River).
