Hemibagrus fortis ( Popta, 1904 )

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 : 239-241

Hemibagrus fortis ( Popta, 1904)

( Fig. 25 )

Macrones fortis Popta, 1904: 185 (type locality: Bo River, central Borneo); 1906: 44, Pl. 2 Figs. 8a–b .

Macrones howong Popta, 1904: 181 (type locality: Howong River, Mahakam drainage, Borneo); 1906: 32, Pl. 1 Fig. 4 .

Macrones bo Popta, 1904: 183 (type locality: Bo River, Mahakam drainage, Borneo); 1906: 38, Pl. 2 Fig. 6 .

Macrones kajan Popta, 1904: 184 (type locality: Kajan River, Mahakam drainage, Borneo); 1906: 41, Pl. 2 Fig. 7 .

Macrones nemurus (non Valenciennes, in Cuvier & Valenciennes, 1840) - Vaillant, 1902: 54 (in part); Weber & de Beaufort, 1913: 341 (in part); (?) Rendahl, 1922: 201; Hardenberg, 1935: 234.

Mystus nemurus (non Valenciennes, in Cuvier & Valenciennes, 1840) - Inger & Chin, 1962: 138, Fig. 69 (in part); Samat, 1990: 343; Christensen, 1992: 600; Kottelat et al., 1993: 66 (in part; not pl. 31); Kottelat, 1994: 412; Chin & Samat, 1995: 23; Chin, 1996: 303.

Hemibagrus nemurus (non Valenciennes, in Cuvier & Valenciennes, 1840) - Lim & Wong, 1994: 53.

Hemibagrus aff. nemurus - Martin-Smith & Tan, 1998: 589.

Hemibagrus fortis - Tan & Ng, 2000: 272 (first revisers); Parenti & Lim, 2005: 189; Ferraris, 2007: 88 (in part).

Material examined. — BORNEO: Sarawak: ANSP 170232 , 34 ex., 60.8–173.4 mm SL, Sungai Lawa, gravel area about 1.0 km up from confluence with Batang Baram, 3°30'N 114°27'E ; USNM 324566 , 8 ex., 63.2–170.5 mm SL, Batang Balui , tributary stream, Batang Kuro ; USNM 324989 , 10 ex., 24.7–45.3 mm SL, Baleh River , tributary entering river in part of river opposite school, Sekolah Negara Bawai ; USNM 324991 , 1 ex., 39.5 mm SL, Batang Balui, tributary stream, Batang Taman , where it enters Batang Balui USNM 325033 , 1 ex., 54.8 mm SL , USNM 325039 18 ex., 33.0- 107.1 mm SL, Batang Balui , tributary stream, Sungai Doh Leng ; USNM 325323 , 3 ex., 106.6–152.9 mm SL, Batang Balui, tributary stream, Long Tow where it enters from Batang Balui just downstream of logging camp ; USNM 325325 , 2 ex., 126.1–130.2 mm SL, Batang Balui , tributary stream, Batang Luan ; USNM 325326 , 33 ex., 29.4–197.0 mm SL, Batang Balui , tributary stream, Long Ulu ; USNM 325327 , 2 ex., 243.3–265.3 mm SL, Kapit town morning market ; USNM 325386 , 1 ex., 104.2 mm SL, Batang Balui, tributary stream, Long Tanyit , where it enters Batang Balui ; USNM 325397 , 2 ex., 77.1–127.6 mm SL, Baleh River , southern tributary just E of confluence of Mujang and Baleh Rivers ; USNM 325401 , 1 ex., 129.0 mm SL, Batang Balui , tributary stream, Batang Luan Paha ; USNM 325403 , 3 ex., 61.0– 145.2 mm SL, Batang Balui , tributary stream, Kemtu ; USNM 325404 , 2 ex., 155.9–169.0 mm SL, Batang Balui , tributary stream, Jangan Umi flowing into Batang Besua ; USNM 325406 , 158 ex., 28.0– 148.9 mm SL, Baleh River , creek entering northern bank approximately 5 km E of Sut River ; USNM 325407 , 10 ex., 36.6–170.6 mm SL, Baleh River , southern tributary stream opposite logging camp just E of confluence of Baleh and Mujong Rivers ; ZRC 37709, 1 ex., 189.2 mm SL, Lanjak Entimau Wildlife Sanctuary .

BORNEO: Kalimantan Tengah: BMNH 1997.7.17.22–29, 8 ex., 60.4–134.6 mm SL, Sungai Batu-Ngiring, a tributary of Sungai Kerendan (a tributary of Sungai Lahei) approximately 2 km upstream from Sungai Paku-Merah ; BMNH 1997.7.17.32–41, 10 ex., 41.2–186.2 mm SL, Sungai Idow, below a waterfall approximately 7 km upstream from Sungai Kerendan (a tributary of Sungai Lahei) ; BMNH 1997.7.17.42–51, 8 ex., 33.0– 147.6 mm SL, Barito River drainage, Sungai Mata, a small tributary at Sungai Barito approximately 2 km below Muara Laung ; BMNH 1997.7.17.52–58, 7 ex., 34.8-175.6 mm SL, Sungai Panganen, a small tributary of Sungai Laung approximately 1 km from Muara Laung ; BMNH 1997.7.17.59–64, 6 ex., 38.4–190.1 mm SL, Barito River drainage, Sungai Tarusan, a small tributary of Sungai Laung, approximately 1 km upstream from Dessa Maruwei. BMNH 2000.10 .25.1289, 1 ex., 98.0 mm SL, Barito River approximately 2 km below Muara Laung ; BMNH 2000.10.25.1359–1363, 3 ex., 101.6–176.5 mm SL, Barito River at Muara Laung ; BMNH 2001.1 .15.181, 1 ex., 194.4 mm SL, Sungai Busang ; BMNH 2001.1 .15.200, 1 ex., 210.7 mm SL, Sungai Busang ; BMNH 2001.1.15.234–241, 8 ex., 50.9–78.1 mm SL, markets at Muara Teweh and Puruk Cahu ; BMNH 2001.1 .15.1338, 1 ex., 107.8 mm SL, Sungai Lahei and surrounding habitats, at Desa Kerendan .

BORNEO: Sabah: FMNH 44844 , 1 ex., 245.0 mm SL, Kinabatangan district, Lamag ; FMNH 44845 , 1 ex., 63.2 mm SL, Kinabatangan district, Bukit Kretam camp, Sungai Gaja ; FMNH 44846 , 1 ex., 99.3 mm SL, Kinabatangan district, Danau Bukit Garam ; FMNH 44847 , 3 ex., 83.1–129.1 mm SL, Labuk district, Labuk River ; FMNH 44848 , 4 ex., 103.5–158.3 mm SL, Sandakan district, Km 25, N road ; FMNH 44849 , 1 ex., 50.2 mm SL, Kota Belud district, Tempasuk River ; FMNH 44852 , 3 ex., 125.3–195.4 mm SL, Sandakan district, Gum Gum River ; FMNH 51713 , 22 ex., 68.9–157.4 mm SL ; FMNH 51714 , 10 ex., 44.3–196.3 mm SL ; FMNH 51715 , 3 ex., 154.7–209.7 mm SL ; FMNH 51716 , 9 ex., 157.3–212.0 mm SL, Kinabatangan district ; FMNH 68053 , 24 ex., 59.7–203.8 mm SL ; FMNH 68054 , 47 ex., 41.0– 179.7 mm SL, Kalabakan, Sungai Tibas camp, Sungai Tawan ; FMNH 68055 , 2 ex., 157.0– 159.2 mm SL ; FMNH 68056 , 3 ex., 107.1–152.9 mm SL ; FMNH 68071 , 10 ex., 37.7–228.0 mm SL ; FMNH 68072 , 5 ex., 120.0– 160.8 mm SL ; FMNH 68073 , 7 ex., 83.1–134.1 mm SL ; FMNH 68074 , 9 ex., 97.0– 187.3 mm SL ; FMNH 68075 , 1 ex., 126.7 mm SL ; FMNH 68076 , 12 ex., 98.7–141.8 mm SL ; FMNH 68077 , 13 ex., 110.5–230.2 mm SL ; FMNH 68078 , 1 ex., 51.0 mm SL ; FMNH 68079 , 1 ex., 78.8 mm SL ; FMNH 68082 , 2 ex., 43.9–51.2 mm SL, Kinabatangan district, Deramakot camp . FMNH 68057 , 30 ex., 21.9–187.8 mm SL, Tawau district, Kalabakan, Sungai Marikut ; FMNH 68069 , 2 ex., 106.9–124.6 mm SL, Kinabatangan district , 1 mile above Sungai Tabalin Besar ; FMNH 68070 , 1 ex., 92.5 mm SL , FMNH 68083 , 2 ex., 40.5–48.8 mm SL, Kinabatangan district, below mouth of Malubok River ; FMNH 68080 , 1 ex., 137.4 mm SL, Kalabakan, Kalabakan River, near Sungai Maga ; FMNH 68410 , 16 ex., 55.8–136.4 mm SL, Tuaram district, Tuaram River at Kiulu ; FMNH 68565 , 1 ex., 52.9 mm SL, Tambunan district, Sungai Kaingeran ; FMNH 96271 , 1 ex., 156.6 mm SL, Kota Kinabalu ; FMNH 99432 , 1 ex., 29.6 mm SL, Kota Marudu, Marak Parak, Sungai Khidingon . ZRC 40521, 1 ex., 190.0 mm SL, Danum, Sepat Kalisun stream ; ZRC 40522, 1 ex., 126.9 mm SL, Danum, Sungai Palum Tambun, tributary of Sungai Segama upstream of Danum Valley Field Centre ; ZRC 40529, 2 ex., 31.8–74.5 mm SL, Sabah : Danum Valley .

BORNEO: Kalimantan Timur: ZRC 45519, 1 ex., 217.6 mm SL, Kalimantan Timur: Kayan drainage, Bahau, Lobok , a cut-off section of Bahau River near Kuala En’ggeng B’io, 2°52'16.8"N 115°49'28.8"E ; ZRC 45525, 10 ex., 61.9–137.5 mm SL, Kalimantan Timur: Kayan drainage, Kayan River at mouth of Sungai Pingai ; ZRC 45606, 1 ex., 186.4 mm SL, Kalimantan Timur: Kayan drainage, Bahau River ; ZRC 45640, 6 ex., 41.7–127.1 mm SL, Kalimantan Timur: Kayan drainage, Bahau, Sungai En’ggeng I’nt, approx. 200–300 m downstream of Kuala En’ggeng B’io 2°51'30.6"N 115°49'40.8"E ; ZRC 45654, 7 ex., 81.5–114.5 mm SL, Kalimantan Timur: Kayan drainage, Bahau, Lalut Birai, next to Lalut Birai field station, feeder stream to En’ggeng B’io which drains into Bahau River , 2°52'34.8"N 115°49'11.4"E ; RMNH 7551 , 4 syntypes, 54.4–272.0 mm SL, Bo ; CAS 93909, 3 ex., 55.8–145.2 mm SL, Sungai Belayan, approx. 8–9 km upriver from Tabang ; RMNH 7547 , 1 ex., 106.4 mm SL, Howong [holotype of Macrones howong ] ; RMNH 7549 , 1 ex., 134.5 mm SL, Bo [holotype of Macrones bo] ; RMNH 7550 , 1 ex., 122.7 mm SL, Kajan [holotype of Macrones kajan ] .

Diagnosis. — Hemibagrus fortis is distinguished from congeners in the H. nemurus species group in having the branches of the dorsal-fin rays of almost equal length (vs. anteriormost branch of dorsal-fin rays longer than other branches) giving the dorsal fin a rounded (vs. distinctly jagged) distal margin ( Fig. 20 ), and, except for H. capitulum and H. hoevenii in having a longer, lower adipose fin (maximum height of adipose fin 2.8–4.9 times in the length of its base vs. 1.7–3.2). It further differs from H. hoevenii in having the premaxillary tooth band not (vs. partially) exposed when the mouth is closed, rounded (vs. tapering) caudal-fin lobes, absence (vs. presence) of a broad and conspicuous dark margin around the caudal fin, a rounded (vs. triangular) anal fin and broader membranes of the dorsal fin which give it a rounded (vs. triangular) appearance, from H. nemurus in having a larger eye (16–29% HL vs. 9–15), and from H. spilopterus in having a flat (vs. gently convex) interorbital space.

Description. — Biometric and meristic data as in Table 14. General description as for genus. Head depressed and broad, body moderately compressed; head width 57–77% HL. Interorbital space flat. Eye diameter 16–29% HL. Premaxillary tooth band not exposed when mouth is closed. 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; maximum height 3.3–6.2% SL (2.8–4.9 times in length of adipose-fin base). Adipose-fin origin separated from base of last dorsal-fin ray by distance of 8.7–14.6% SL. Dorsal spine stout, with 2–9 serrations on posterior edge. Branches of each dorsal-fin ray about equal length, imparting rounded distal margin to fin; membranes broad, imparting rounded appearance. Adpressed dorsal fin (excluding filamentous extensions of rays) not reaching adipose fin; filamentous extensions, when present, not reaching beyond middle of adipose-fin base. Pectoral spine stout, with 6–15 large serrations on posterior edge. Anal fin rounded, origin slightly posterior to adipose origin. Caudal fin forked; upper and lower lobes rounded. Maxillary barbels reaching barbels reaching at least vertical through base of last anal-fin ray, sometimes beyond caudal-fin base (258–439% HL). Maximum recorded size 272 mm SL.

Colour. — Dorsal surface of head and body uniform brownish-grey (live or freshly-dead specimens with a yellow hue, fading on preservation); ventral surface of head and body dirty white; adipose fin brownish-grey, without black spot; fin-rays and inter-radial membranes of all fins grey; dorsal surface of barbels brownish-grey, ventral surface dirty white.

Distribution. — Hemibagrus fortis is known only from the upper reaches of river drainages in Borneo (Barito, Kalabakan, Kayan, Mahakam, Rajang and Segama river drainages; Fig. 26 ). It has not (yet) been recorded from the Kapuas River drainage.

Habitat and biology. — A typical habitat for H. fortis consists of a shaded stream or river with a gravel bottom (Watson & Balon, 1984), although the species reportedly favours deep pools (Chin & Samat, 1995). The species has also been caught in clear, fast-flowing streams that are the typical habitat of H. baramensis (see Martin-Smith & Tan, 1998). The diet consists of arthropods (Chin & Samat, 1995).

Remarks. — Macrones fortis , M. howong , M. bo and M. kajan are simultaneous subjective synonyms. Tan & Ng (2000), as first revisers, gave precedence to H. fortis .

Figures

Fig. 25. Hemibagrus fortis, ZRC 45654. 114.5 mm SL, Borneo: Kalimantan Timur, Bahau River drainage.

Fig. 8. Map showing collection localities of Hemibagrus guttatus specimens examined in this study.

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

Fig. 6. Hemibagrus semotus, ZRC 46121, holotype, 126.0 mm SL, Borneo: Sabah, Padas River.

Fig. 7. Hemibagrus guttatus, ZRC 42555, 328.4 mm SL, China: Beijiang river.

Fig. 20. Schematic illustrations of fully extended dorsal fins of members of the H. nemurus species group: a, H. fortis, ZRC 40522, 126.9 mm SL; b, other members of the H. nemurus species group (H. nemurus, ZRC 39181, 132.4 mm SL, illustrated). Scale bar = 10 mm.

Fig. 26. Map showing collection localities of Hemibagrus fortis, H. hoevenii and H. spilopterus specimens examined in this study.