Barilius ornatus Sauvage 1883

Tejavej, Anuratana, 2012, Redescription of Barilius ornatus Sauvage (Cypriniformes: Cyprinidae) with data from a population from the eastern part of the Isthmus of Kra, Thailand, Zootaxa 3586, pp. 148-159 : 149-154

Barilius ornatus Sauvage 1883

( Figure 1A–G)

Barilius ornatus Sauvage 1883: 153–154 (type locality: Menam , Siam, herein restricted to the eastern part of the Isthmus of Kra of southern Thailand).

Diagnosis. A species of Barilius reaching approximately 110 mm SL. Distinguished from all other congeners in Southeast Asia by having 37–40 scales (rarely 36) along lateral line, 6–7 scale rows above lateral line, 17–20 (rarely 16 or 21) predorsal scales, 12–14 circumpeduncular scales, anal-fin origin opposite the 6th branched dorsalfin ray to behind last branched dorsal-fin ray, head depth 17–21% SL, predorsal length not more than 58% SL, dark pigment on dorsal fin concentrated at edge of branched dorsal-fin rays, 1–2 small caudal spots present or absent, generally short and thin rostral and maxillary barbels (if present), and small dentary tubercles.

Description. Morphometric and meristic measurements in Tables 1 and 2 are based on 34 specimens, 46.38–108.88 mm SL. Body shape and coloration are shown in Figs. 1A–G. Body fusiform, deep and compressed with ventral profile more convex than dorsal profile. Head deep and compressed, snout slightly blunt to acute. Caudal peduncle long, narrow near caudal base. Mouth large, oblique, terminal, with maxilla extending from vertical from anterior margin of eye to vertical from posterior edge of pupil. In some specimens, snout projects beyond lower jaw, and in a few specimens, lower jaw projects beyond upper jaw. Lower jaw with no notch or slight notch with corresponding emargination in upper jaw. Two pairs of barbels (often missing on either side): rostral and maxillary barbels generally short and tiny, often rudimentary, with rostral barbel length generally far shorter than 50% of distance between origin of rostral barbel and corner of mouth. Rostral barbel often under rostral groove. Eye large but size generally decreases with body length, from diameter longer than snout in small specimens to slightly shorter than snout in large specimens. Infraorbital bones large. Presumed fully developed male with greatly enlarged chest ( Figs. 1B and E).

Scales. 37–40 scales in lateral-line row to end of hypural plate (rarely 36), 2–4 scales more to the end of caudal base. 6–7 scale rows above lateral line (predorsal scale row not included), 2–4 rows below lateral line; 17–20 scales in predorsal row (rarely 16 or 21); 12–14 circumpeduncular scales. Axillary process at the anterior base of pectoral fin and axillary scale at the anterior base of pelvic fin well developed.

were provided by Chaiwut Grudpan. Number and length of maxillary barbels of type specimens from Kottelat (1984).

Fins. Dorsal fin origin behind vertical to origin of pelvic fin and in posterior half of body (not including caudal fin). Dorsal fin with 2–3 simple rays and 7–8 branched rays, straight to slightly concave in most specimens; convex with middle and posterior branched rays lengthened in presumed alpha male, the posterior tip sometimes surpasses vertical from posterior base of anal fin in presumed alpha male ( Figs. 1B and E). Anal-fin origin at vertical from 6th branched ray to behind last branched dorsal-fin ray at distance of up to 3 times width between two dorsal branched rays,. Anal fin with 2–3 simple rays and 9–11 branched rays; first 3–4 branched rays elongated, creating concave margin; in presumed alpha male margin is less concave or straight. Lower lobe of caudal fin longer or equal to upper lobe. Pectoral fin large, with 12–15 rays, often reaches anterior base of pelvic fin. Pelvic-fin origin far in front of dorsal-fin origin, anterior ray not reaching origin of anal fin, with 8–9 rays, posterior ray generally not reaching anterior origin of anal fin but often reaching anterior origin of anal fin in presumed developed male.

Tuberculation. In presumed fully developed males, numerous small tubercles cover the whole body, head and parts of fins ( Figs. 1B and E). Dentary tubercles on highly tuberculated males generally up to 5 incomplete rows in large specimens, anterior ones larger than posterior ones, more distinct on outer and inner edges of dentary. Small tubercles on side of snout, end of maxilla, front of eye, top of eye, all areas below eye, opercle and branchiostegal region. Larger tubercles on entire side of body, generally up to 4 tubercles per scale in large specimens. Small and large tubercles on snout, top of head, and back. Tubercles on presumed fully developed males also cover outer surface of pectoral and pelvic fins, part of dorsal and anal fins, and the upper lobe of caudal fin. In normal specimens tubercles restricted mainly to snout and dentary, and in these specimens they are not as numerous nor as large as tubercles on presumed fully developed male.

Coloration (live and fresh specimens). Dorsum greenish to grayish, side silvery to greenish or bluish depending on light angle; belly silvery in most specimens but some specimens with slightly reddish-orange to bronze belly ( Figs. 1D, F–G). Presumed fully developed dominant males ( Fig. 1E) often with slightly reddishorange to bronze belly, excluding lower jaw region. Side with 8–14 blue to green vertical bars (not including the caudal spot), each bar generally 1–2 scales wide; most bars in front of anal fin generally reach or cross lateral line, but in some specimens these bars do not reach lateral line and appear as spots or disappear (but reappear in preservation). Bars often broken into double bars both vertically and horizontally; number of bars on either side of the body often unequal. Caudal spot, if present, does not extend far beyond caudal scale margins into anterior region of caudal fin. Sometimes two caudal spots align vertically. All bars may become indistinct depending on light reflection and mood of the fish, and sometimes become hard to distinguish. Pectoral and pelvic fins clear to yellowish or orange. Pelvic fins sometimes with small, whitish anterior and posterior margins. Anal fin clear to yellow to reddish-orange, sometimes with small, whitish anterior tip. Caudal fin with dark margins on principal rays, outer parts of branched rays, and whole branched rays in middle of fin; caudal-fin membrane clear to yellowish, sometimes with small light margin before dark margin. Dorsal fin clear to orangish or pinkish, with dark pigment on rays and membrane, concentrated at edge of dorsal-fin rays. In most specimens dark pigment on first 3–5 branched dorsal rays do not reach tip of fin, leaving it clear to white; in presumed developed male dark pigment expands to anterior tip of dorsal fin.

Coloration (preserved). Silvery, white, red, and green colorations usually disappear. Dorsum dark brown to dark gray; ventral areas lighter. All dark pigment in fins, body bars and caudal blotch turns dark brown to black. Dark, thin horizontal stripe occasionally appears midlaterally, from behind opercle to caudal base.

Distribution. Barilius ornatus is restricted to streams and rivers in Chumphon Province in southern Thailand, mainly in the Tha Sae drainage ( Fig. 2). Chumphon Province occupies the eastern part of the Isthmus of Kra.

Habitat. Barilius ornatus is found in running waters of various types from small, slow streams to fast rivers with mud, sand or gravel substrates. Among various fishes found with it such as Rasbora paucisqualis , Rasbora trilineata , Rasbora paviana , Hampala macrolepidota , Homaloptera sp. , Nemacheilus masyae , Pangio sp. , Xenenthodon sp. , the most notable one is Poropuntius genyognathus which was described and previously reported to be in Tenasserim Basin in Myanmar ( Roberts 1998). It was found by the author from the area east of Tenasserim from the lower part of Prachuap Khiri Khan Province down to the eastern part of Surat Thani Province.

Material examined. MNHN A-5074 (lectotype), 90.3 mm SL, Menam, Thailand, 1882, Harmand , examined by C. Grudpan . MNHN B-2981 (paralectotype), 91.1 mm SL, same data, examined by C. Grudpan . UNMF 00579 (6 specimens) 53.3–94.9 mm SL, Tarn Lord Yai Cave , Sawi District, Chumphon Province, Thailand, 21 January 2003 , S. Janekitkarn and O. Chamason . UNMF 00580 (5 specimens) 46.38–108.88 mm SL, Klong Nam Lord, Wang Mai County, Muang District , Chumphon Province, Thailand, 9 April 2004 . UNMF 00581 (8 specimens) 50.3–91.7 mm SL, Ban Tha Yai, Tha Sae District , Chumphon Province, Thailand, 9 April 2004 . UNMF 00582 (1 specimen) 93.6 mm SL, bridge at Tha Sae River , Song Phi Nong County, Tha Sae District, Chumphon Province, Thailand, 16 August 2004 . UNMF 00583 (3) 48.8–56.9 mm SL, same location as UNMF 00582, 22 April 2006 . UNMF 00584 (9 specimens) 61.8–76.63 mm SL, sand dredging site at Tha Sae River near Tha Sae District, Chumphon Province, Thailand, 15 August 2004 .