Hemibagrus velox Tan & Ng, 2000

Ng, Heok Hee & Kottelat, Maurice, 2013, Revision Of The Asian Catfish Genus Hemibagrus Bleeker, 1862 (Teleostei: Siluriformes: Bagridae), Raffles Bulletin of Zoology 61 (1), pp. 205-291 : 259-261

Hemibagrus velox Tan & Ng, 2000

( Fig. 37 )

Hemibagrus velox Tan & Ng, 2000: 272 , Figs. 2–4 (type locality: Sungai Dareh, Sumatra); Ferraris, 2007: 91; Ng & Lim, 2008: 30.

Bagrus planiceps (non Valenciennes, in Cuvier & Valenciennes, 1840) - Bleeker, 1855c: 260; 1857a: 25; 1858e: 154 (in part); 1859a: 338; 1859b: 339; 1859g: 134 (in part); 1860a: 8, 46.

Hemibagrus planiceps (non Valenciennes, in Cuvier & Valenciennes, 1840) - Bleeker, 1862: 56, Pl. 71 (in part); Hubrecht, 1887: 11.

Macrones planiceps (non Valenciennes, in Cuvier & Valenciennes, 1840) - Günther, 1864: 81 (in part); Boulenger, 1890: 39; Weber, 1894: 420; Volz, 1904: 468; 1907: 166–167; Weber and de Beaufort 1913: 342–343 (in part); Regan, 1920: 308.

Mystus planiceps (non Valenciennes, in Cuvier & Valenciennes, 1840) - Kottelat et al., 1993: 66 (in part).

Material examined. — SUMATRA: Sumatera Utara: BMNH 1889.11.12:61, 1 ex., 224.0 mm SL, Medan ; CMK 4441 , 1 ex., 187.4 mm SL , CMK 4455 , 1 ex., 75.3 mm SL, Sungai Seruai at Biru Biru ; MCZ 57967, 1 ex., 128.4 mm SL, Boharok River about 1 km from Bukit Lawang ; ZMA 121.813 , 1 ex., 129.0 mm SL, Serdang, Sungai Ular .

SUMATRA: Riau: CMK 9038 , 1 paratype, 132.3 mm SL, Kecamatan Seberida, Sungai Gangsal .

SUMATRA: Sumatera Barat: MZB 9305 , holotype , 175.0 mm SL; ZRC 41505, 23 paratypes , 68.7–162 mm SL; UMMZ 243334 , 6 ex. ,

44.1–208.2 mm SL, Sungai Dareh, Pulau Punjung market. ZMA 121.627 , 5 paratypes, 162.0–185.0 mm SL, highlands of Padang, Batang Pangian . ZMA 121.628 , 3 paratypes, 238.0–357.0 mm SL, highlands of Padang, Batang Pangian, from the cave of Buo . ZMA 121.629 , 1 paratype, 264.0 mm SL, highlands of Padang, Batang Sario near Puntian (Kumanis) . UMMZ 243333 , 5 ex., 114.6–234.6 mm SL, market at Kiliranjao .

SUMATRA: Jambi: ZRC 40549, 1 paratype, 269.0 mm SL ; ZRC 40550, 2 paratypes, 236.0, 249.0 mm SL ; ZRC 41503, 3 paratypes, 145.2–199.0 mm SL, Kerinci, Sungaipenuh market . BMNH 1915.8.24:12, 1 ex., 212.0 mm SL, Lake Kerinci .

SUMATRA: Sumatera Selatan: UMMZ 155685 , 4 paratypes, 191.4–263.6 mm SL , UMMZ 155717 , 2 paratypes, 240.3–276.9 mm SL ; UMMZ 155718 , 3 paratypes, 261.8–277.0 mm SL, Danau Ranau .

Diagnosis. — Hemibagrus velox differs from H. bongan in having slightly more vertebrae (50–52, mode=52 vs. 48–50, mode=49), a relatively longer genital papilla in the males (reaching anal-fin origin, vs. not reaching), and the upper lobe of the caudal fin regularly tapering with principal ray produced into a filament (vs. upper lobe rounded posteriorly with principal ray not produced into a filament), from H. divaricatus in having a deeper adipose fin (maximum height 3.1–4.4 times in length of base vs. 1.9–3.2), a more slender caudal peduncle (6.2–7.5% SL vs. 7.3–8.0) and longer inner mandibular barbels (42–57% HL vs. 37–44), and from H. gracilis in having a relatively longer genital papilla in the males (reaching anal-fin origin, vs. not reaching), the genital papilla located nearer the anus (anus separated from genital papilla by a distance of 4.3–5.9% SL vs. 5.4–7.6) and irregular (vs. regular) serrations on the posterior edge of the dorsal spine. It is distinguished from H. lacustrinus in having a longer dorsal to adipose distance (13.2–17.5% SL vs. 7.6– 10.9; adpressed dorsal fin not reaching vs. reaching origin of the adipose fin) and a shorter adipose-fin base (13.0–17.9% SL vs. 18.8–20.4), and from H. planiceps in having more vertebrae (50–52, mode=52 vs. 47–49, mode=47), a relatively longer genital papilla in the males (reaching anal-fin origin, vs. not reaching), the upper lobe of the caudal fin regularly tapering (vs. rounded posteriorly), and more branchiostegal rays (10–11 vs. 8–10).

Description. — Biometric and meristic data as in Table 23. General description as for genus. Head depressed and broad, body moderately compressed. Snout length 33–39% HL. Interorbital distance 29–34% HL. Eye diameter 14–24% HL. Dorsal profile rising evenly but not steeply from tip of snout to origin of dorsal fin, then sloping gently ventrally from there to end of caudal peduncle. Ventral profile horizontal to origin of anal fin, then sloping dorsally to end of caudal peduncle. Adipose-fin base short, approximately as long as anal-fin base (13.0–17.9% SL); maximum height 3.1–4.4 times in length of base; separated from base of last dorsal-fin ray by distance of 13.2–17.5% SL. Dorsal spine stout, with 0–9 irregular serrations on posterior edge; length 10.0–14.3% SL. Adpressed dorsal fin not reaching adipose-fin origin. Pectoral spine stout, with 12–23 large serrations on posterior edge; length 15.3–17.6% SL. Anal-fin origin slightly posterior to adipose-fin origin. Caudal-peduncle depth 6.2–7.5% SL. Caudal fin forked; upper lobe tapering with principal ray produced into a filament, lower lobe rounded posteriorly. Maxillary-barbel length 186–251% HL. Inner mandibularbarbel length 42–57% HL. Vertebrae 50–52. Branchiostegal rays. Maximum recorded size 357 mm SL.

Males with elongate genital papilla reaching to origin of anal fin. Anus separated from genital appendages of both sexes by 4.3–5.9% SL.

Colour. — Dorsal surface of head and body uniform light grey to grey (live or freshly-dead specimens with yellowish hue, fading in preserved specimens); lateral line cream to yellow; ventral surface of head and body dirty white; adipose fin and fin rays of all fins grey; inter-radial membranes of all fins dirty yellow.

Distribution. — Known from the Batang Hari, Deli, Indragiri, and Musi River drainages in Sumatra ( Fig. 32 ).

Habitat. — Hemibagrus velox is known primarily from large, swift-flowing rivers with a substrate composed predominantly of gravel and rock, although it has also been found in some of the large volcanic lakes (excluding Danau Singkarak) in the Barisan range in western Sumatra.

Figures

Fig.37. Hemibagrus velox, UMMZ 243334, 174.3 mm SL; Sumatra: Sungai Dareh.

Fig.2. Hemibagrus baramensis, ZRC 42742, 150.0 mm SL; Borneo: Sarawak, Mulu.

Fig.3. Map showing collection localities ofHemibagrus baramensis specimens examined in this study.

Fig. 4. Hemibagrus sabanus, ZRC 40493, 104.9 mm SL, Borneo: Sabah, Segama River.

Fig.32. Map showing collection localities ofHemibagrus planiceps, H. bongan, H. divaricatus, H. gracilis, H. lacustrinus, and H. velox specimens examined in this study.