Search

Gastromyzon ocellatus group Diagnosis.-This species group is defined by an angular gill slit; a distinct subopercular groove, which is continuous to the pectoral fin origin; a reddish orange caudal fin in life; absence of a secondary rostrum; absence of a postoral pouch; absence of scales on abdomen; and dorsum of body with 7-10 cream bars., Published as part of H. H. Tan & C. U. M. Leh, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from southern Sarawak., pp. 1-19 in Zootaxa 1126 on page 14

Gastromyzon aeroides, new species Figs. 3-4 Gastromyzon ridens (non Roberts) - Choy & Chin, 1994: 762; Kottelat & Lim, 1995: 235 Gastromyzon monticola (non Vaillant) - Chin, 1990: SC-22 (part); Rahim et al., 2001: 126. Material examined: SABAH (Mengalong River basin): HOLOTYPE: MUS uncatalogued, 38.8 mm SL; Sipitang: Sungai Malamum, ca. 9 km into track, tributary to Mengalong River (04��59.120'N115��37.581'E [50 m asl]); H. H. Tan, K. K. P. Lim & R. Goh, 9 Dec 2000. PARATYPES: MUS uncatalogued, 3 ex., 32.6-34.7 mm SL; ZRC 47021, 4 ex., 32.1- 43.4 mm SL; same locality as holotype. SABAH (Padas River basin): ZRC 47022, 7 ex., 35.0-45.9 mm SL; Keningau: Sungai Agudon, mile 1 from Keningau to Crocker Range National Park headquarters, (05��21.206'N116��07.532'E [395 m asl]); H. H. Tan, K. K. P. Lim & R. Goh, 7 Dec 2000. NON-TYPE MATERIAL: SABAH (Petagas River basin): ZRC 47023, 3 ex., 37.7- 44.4 mm SL; Penampang: Penampang River, Sungai Moyog, Kampong Kibunut (05��53.301'N116��14.102'E [225 m asl]); H. H. Tan, K. K. P. Lim & R Goh, 10 Dec 2000. BRUNEI DARUSSALAM (Temburong district: Temburong River basin): UBD-B-1a, 1 ex., 33.0 mm SL; ZRC 38760, 2 ex., 33.3-37.8 mm SL; Sungai Belalong at Kuala Belalong; K. K. P. Lim et al., 14-17 Jun 1995. ZRC 47024, 5 ex., 31.0-34.4 mm SL; Sungai Belalong, in front and near to the Kuala Belalong Field Studies Centre (04��32'50.4"N115��09'27.6"E [80 m asl]); H. H. Tan & K. K. P. Lim, 4-7 Oct 2001. UBD- SC/92/7/F5a, 1 ex., 41.9 mm SL; Sungai Belalong, Kuala Belalong Field Study Centre; S. Choy, 27 Jul 1992. Diagnosis. Gastromyzon aeroides differs from its congeners in having the following unique combination of characters: angular gill slit; subopercular groove present and continuous to pectoral fin origin; body, including dorsum, brown; head dorsum with very fine cream reticulate pattern (similar to a cream head with brown spots and blotches); dorsal, caudal and anal fins blue in life; presence of sublacrymal groove; snout rounded when viewed dorsally; absence of secondary rostrum; absence of postoral pouch; scales absent on belly; 47-65 scales in lateral line (Sabah population: 56-65, Brunei population: 47-49); pelvic fin not overlapping level of anal fin origin, adpressed dorsal fin falling short of level of anal fin origin. Maximum size: 45.9 mm SL (ZRC 47022). Description. General body shape and appearance as in Figs. 3-4. Meristic and morphometric data appear in Table 1. Head rounded in dorsal view; relatively long (27.9- 32.5 % SL) and wide (23.5-30.7 % SL, 83.1-100.0 % HL), head relatively flattened (head depth 12.6-15.2 % SL, 42.3-52.7 % HL); snout relatively long (snout length 59.6-70.3 % HL). Tubercles over entire head and anterior half of body. Sublacrymal groove present, not visible from side. Angular gill slit. Subopercular groove present and continuous to pectoral fin origin. Postoral pouch absent. No scales on belly. Posterior part of pectoral fin overlapping pelvic fin origin. Pelvic fin not reaching level of anal fin origin. Pectoral and pelvic fins with serrae on anteriormost rays. Dorsal fin situated at about mid body (predorsal length 53.8-60.4 % SL). Adpressed dorsal fin falling short of level of anal-fin origin. Deepest part of body at dorsal-fin origin (body depth at dorsal-fin origin 17.7-21.4 % SL). Anus situated just behind posterior margin of pelvic fin base. Caudal peduncle relatively deep (9.5-11.2 % SL) and short (6.8-9.6 % SL). Body pigmentation and life coloration. See Fig. 3. Body uniform brown on dorsum and sides; a white spot on posterior edge of every body scale; ventrum cream. Head dorsum brown, with fine cream reticulate pattern (i.e. reticulations very dense, the head creamy with brown spots and blotches). Dorsal fin with 4 irregular black bars, the subdistal bar the most complete; interradial membranes and margin of fin blue; anterobasal black spot present. Caudal fin with 4-5 black bars, the interradial membranes and margin of fin blue (blue most intense in middle of fin). Anal fin with 2 faint black bars, the interradial membranes and margin of fin blue. Pectoral and pelvic fins brown with fine cream reticulate pattern and a brown margin. Pelvic axillary flap brown. Colour in alcohol. See Fig. 4. Body black on dorsum and sides; ventrum cream. Head dorsum black. Dorsal fin grey with 4 irregular black bars, the subdistal bar most complete, interradial membranes and margin hyaline; fin with antero-basal black spot. Caudal fin grey, with 4-5 black bars, the interradial membranes and margin hyaline. Anal fin grey, with 2 faint black bars, the edges hyaline. Pectoral and pelvic fins greyish-black, with marked hyaline margin. Pelvic axillary flap dark grey. Remarks. In addition to the characters mentioned in the diagnosis, G. aeroides can be differentiated from other congeners of the G. punctulatus group by the following characters: dorsal, caudal and anal fins blue in life (vs. yellow in G. punctulatus); head rounded in dorsal view (vs. head truncate in G. punctulatus); body plain (vs. spotted in G. punctulatus); caudal peduncle depth greater than in G. punctulatus (13.0-15.1 vs. 12.0- 13.9 % BL). The populations of G. aeroides in Brunei and Sabah exhibit some differences, the most prominent being the range of lateral scale counts. The Brunei population has 47-49 lateral line scales, whereas the Sabah population has 56-65 scales. However, based on present limited material available, the two populations cannot otherwise be readily discerned. Distribution. Gastromyzon aeroides is found in the Petagas, Padas and Mengalong river basins in western Sabah and in the Temburong River basin in Brunei Darussalam (Fig. 7). Etymology. From the Latin aeroides, meaning sky-blue. This is in allusion to the blue dorsal, anal and caudal fins in life. Used as a noun. Field notes. Syntopic species of Balitoridae include: G. lepidogaster (Padas River basin); G. borneensis, G. lepidogaster (Mengalong River basin); and G. cranbrooki, G. lepidogaster, G. punctulatus, G. venustus and Neogastromyzon sp. (Temburong River basin)., Published as part of H. H. Tan & Z. H. Sulaiman, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from the Temburong River basin, Brunei Darussalam, Borneo., pp. 1-19 in Zootaxa 1117 on pages 9-13

[[Gastromyzon]] The genus Gastromyzon, a unique group of fishes endemic to the island of Borneo, exhibits extreme morphological adaptations for life in torrential waters. The included species, which are obligate bottom dwellers, are poor swimmers that have lost the ability to hover or swim in mid-water. As a consequence, the genus has evolved new modes of locomotion, which involve creeping and crawling along the bottom. Balitorid locomotion had been studied by Wickler (1971) using aquarium stocks of G. ctenocephalus (misidentified as G. borneensis). He found that the horizontally oriented pectoral fins, fused pelvic fins, and depressed head and body collectively form a suction cup that enables the fish to adhere to the submerged rock substrate of fast flowing streams. The genera Gastromyzon, Hypergastromyzon and Neogastromyzon are characterized by fused pelvic fins; and a higher number of branched pectoral and pelvic-fin rays (numbering 20-30 and 16-24 respectively) than are found in the other 250 or more species of cyprinoids in the Sunda Islands, in which the number of branched pectoral rays does not usually exceed 17 and branched pelvic rays does not exceed 12 (and is usually not more than 8; Inger & Chin, 1961). Unicellular horny projections, or unculi, on the ventral surfaces of the fish���s body apparently also serve to increase adhesion on smooth rocky surfaces (Roberts, 1982a, 1982b, 1989)., Published as part of H. H. Tan & Z. H. Sulaiman, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from the Temburong River basin, Brunei Darussalam, Borneo., pp. 1-19 in Zootaxa 1117 on page 1

[[Gastromyzon]] The genus Gastromyzon, which is endemic to Borneo, exhibits extreme external morphological adaptations for life in torrential waters. Obligate bottom dwellers, the included species have lost the ability to hover or swim in the mid-water column, and as a consequence have evolved new modes of locomotion, which involve creeping and crawling over submerged rocks. Locomotion in the genus has been studied by Wickler (1971) using aquarium stocks of G. ctenocephalus (misidentified as G. borneensis). The horizontally oriented pectoral fins, fused pelvic fins, and depressed head and body collectively form a suction cup, which enables the fish to adhere to the submerged rocky substrate of fast-flowing stream habitats. In addition, the genus is characterized by greater numbers of pectoral and pelvic-fin rays, these numbering 20-30 and 16-24 branched rays, respectively. This compares to the other 250 or more species of cyprinoids in the Sunda Islands, in which the number of branched pectoral rays usually does not exceed 17 and the number of branched pelvic rays does not exceed 12 (with the latter usually no more than 8; Inger & Chin, 1961). Unicellular horny projections, or unculi, on the ventral surfaces of the fish apparently also serve to increase adhesion on smooth rock surfaces (Roberts, 1982a, 1982b, 1989). The morphological adaptations described above are shared by the closely related balitorid genera Hypergastromyzon and Neogastromyzon, which are also endemic to Borneo. During the course of a taxonomic revision of Gastromyzon, collaborations were made with regional scientists to facilitate research and collections, which resulted in discovery of the three new species described in this paper.

Gastromyzon venustus, new species Figs. 5-6 Gastromyzon monticola (non Vaillant) - Choy & Chin, 1994: 762. Material examined: BRUNEI DARUSSALAM (Temburong district: Temburong River basin): HOLOTYPE: UBD uncatalogued, 38.8 mm SL; Sungai Belalong, in front and near to the Kuala Belalong Field Studies Centre (04��32'50.4"N115��09'27.6"E [80 m asl]); H. H. Tan & K. K. P. Lim, 4-7 Oct 2001. PARATYPES: UBD uncatalogued, 3 ex., 37.4-39.6 mm SL; ZRC 47104, 4 ex., 36.6-49.4 mm SL; same locality as holotype. NON-TYPE MATERIAL: BRUNEI DARUSSALAM (Temburong district: Temburong basin): UBD-B-1b, 1 ex., 39.0 mm SL; ZRC 38777, 1 ex., 33.7 mm SL; Sungai Temburong, about 1 km downstream of Kuala Belalong; K. K. P. Lim et al., 16 Jun 1995. UBD-SC/92/7/F5b, 2 ex., 28.1-41.5 mm SL; Sungai Belalong, Kuala Belalong Field Study Centre; S. Choy, 27 Jul 1992. Diagnosis. Gastromyzon venustus differs from its congeners in having the following unique combination of characters: body plain brown, head dorsum plain brown; dorsal, caudal and anal fins red in life; absence of secondary rostrum; absence of postoral pouch; gill slit angular, subopercular groove present and continuous with pectoral-fin origin; a broadly rounded snout when viewed dorsally; presence of sublacrymal groove; absence of scales on abdomen; 58-63 scales in lateral line; pelvic fin just reaching level of anal fin origin, adpressed dorsal fin not overlapping level of anal fin origin. Maximum size: 49.4 mm SL (ZRC 47104). Description. General body shape and appearance as in Figs. 5-6. Meristic and morphometric data appear in Table 1. Head broadly rounded when viewed dorsally, relatively short (27.5-28.7 % SL) and wide (27.1-28.5 % SL, 95.6-102.8 % HL), head relatively flattened (head depth 12.4-14.5 % SL, 43.7-52.8 % HL). Snout elongated (snout length 63.7-71.7 % HL). Tubercles present over entire snout. Sublacrymal groove present, not visible from side. Gill slit strongly angular. Subopercular groove pronounced and continuous to origin of pectoral fin base. Postoral pouch absent. Scales absent from belly. Posterior part of pectoral fin not overlapping anterior part of pelvic fin in adults, but overlapping in juveniles. Pectoral and pelvic fins with serrae on anteriormost rays. Dorsal fin situated at about mid body (predorsal length 53.9-58.1 % SL). Adpressed dorsal fin not overlapping level of anal fin origin. Deepest part of body at dorsal fin origin (body depth at dorsal fin origin 16.4-18.2 % SL). Anus situated just behind posterior base of fused pelvic fins. Caudal peduncle relatively deep (11.0-11.8 % SL) and long (6.8-10.7 % SL). Body pigmentation and life coloration. See Fig. 5. Body plain yellowish brown, ventrum cream, a tiny golden spot on posterior edge of every body scale. Head dorsum plain yellowish brown. Eye with golden iris. Dorsal fin red with 3 black bars, the subdistal bar most distinct, with interradial membranes and margin red; and with antero-basal black spot. Caudal fin red with 3-4 black bars, anterior central part gold, subdistal band most distinct, with interradial membranes and margin red. Anal fin reddish, with 2 faint black bars and reddish margin. Pectoral and pelvic fins yellowish brown, with reddish margins. Pelvic axillary flap light yellowish brown. Choy and Chin (1994: 762) noted that small individuals have a blackish-blue spotted appearance, particularly if seen under bright sunlight. The fins have red edges and the caudal fin has 4 dark vertical bands. Colour in alcohol. See Fig. 6. Body dark brown or black, the ventrum cream. Head dorsum black. Dorsal fin red (when freshly preserved) or brown with 3 black bars, the subdistal bar most distinct, with an antero-basal black spot. Caudal fin red (when freshly preserved) or brown with 3-4 black bars, subdistal bar most distinct, hyaline interradial membrane and margin. Anal fin brown with 2 faint black bars, and a hyaline margin. Pectoral and pelvic fins grey, with reddish to hyaline margin. Pelvic axillary flap brown. Remarks. In addition to the characters mentioned in the diagnosis, G. venustus can be further differentiated from other congeners of the G. pariclavis group by the following characters: plain body pattern (vs. barred body in G. pariclavis and reticulated body pattern in G. embalohensis); fewer transverse scales than G. pariclavis (11-13.1.10-12 vs. 15-18.1.14-15); greater dorsal depth than G. embalohensis (19.5-21.7 vs. 18.2-18.9 % SL); greater body depth than G. embalohensis (16.4-18.2 vs. 14.8-15.7 % SL); dorsal fin base length less than G. pariclavis (17.1-20.2 vs. 20.1-22.4 % SL). Distribution. Gastromyzon venustus is known only from Sungai Belalong, Temburong River basin, Brunei Darussalam (Fig. 7). Etymology. From the Latin venustus, meaning charming, beautiful. This is in reference to the distinctive life coloration. An adjective. Field notes. See under G. cranbrooki for list of syntopic species., Published as part of H. H. Tan & Z. H. Sulaiman, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from the Temburong River basin, Brunei Darussalam, Borneo., pp. 1-19 in Zootaxa 1117 on pages 13-18

Gastromyzon punctulatus group Diagnosis. This species group is defined by the following suite of characters: an angular gill slit; presence of a shallow subopercular groove, which extends to the pectoral fin origin; absence of scales on belly; absence of a secondary rostrum; absence of a postoral pouch; and presence of brightly coloured fins in life. Gastromyzon punctulatus is characterized by yellow dorsal, anal and caudal fins, and reddish top and bottom margins to the caudal fin. Gastromyzon aeroides is characterized by blue dorsal, anal and caudal fins., Published as part of H. H. Tan & Z. H. Sulaiman, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from the Temburong River basin, Brunei Darussalam, Borneo., pp. 1-19 in Zootaxa 1117 on page 9

Gastromyzon ctenocephalus group Diagnosis.-This species group is defined by body with evenly distributed cream spots; an angular gill slit; presence of a subopercular groove, which is continuous to the pectoral fin origin; absence of a secondary rostrum; absence of a postoral pouch; absence of scales on abdomen; and small adult size (maximum 40 mm SL)., Published as part of H. H. Tan & C. U. M. Leh, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from southern Sarawak., pp. 1-19 in Zootaxa 1126 on page 3

Gastromyzon borneensis group Diagnosis.-This species group is defined by the following combination of characters: presence of a postoral pouch, just before or at level of pectoral-fin origin; presence of a secondary rostrum (except for G. monticola and G. ornaticauda); a vertical gill slit; absence of a subopercular groove; absence of scales on abdomen; caudal fin with barred pattern (except for G. ornaticauda); and large adult size (maximum 70-95 mm SL)., Published as part of H. H. Tan & Z. H. Sulaiman, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from the Temburong River basin, Brunei Darussalam, Borneo., pp. 1-19 in Zootaxa 1117 on page 3

Gastromyzon farragus, new species Figs. 5-6 Material examined: BORNEO: SARAWAK (Sadong River basin): HOLOTYPE: SM uncatalogued, 30.9 mm SL; Serian, Sungai Kuhas, 6.9 km after Tebelu Tebakang turnoff, 5.8 km inside right side road (01��0910.0���N110��2922.7���E); H. H Tan et al., 5 Sept. 1995. PARATYPES: SM uncatalogued, 6 ex., 17.3-22.8 mm SL; ZRC 47108, 7 ex., paratypes, 15.4-35.9 mm SL; collected with holotype. The following paratypic lots are also from the type locality, but with different collectors and dates of collection, as indicated. ZRC 47109, 6 ex., 15.3-36.1 mm SL; H. H Tan et al., 14 Jan. 1996. ZRC 47110, 6 ex., 24.0-37.1 mm SL; H. H. Tan et al., 19 Feb. 1997. ZRC 47111, 36 ex., 18.7-38.5 mm SL; Honours 98/99 Fish Group, 23 June 1998. NON-TYPE MATERIAL: ZRC 47120, 4 ex., 18.4-28.9 mm SL; Sarawak: Tebedu, Sungai Ahi, on road towards Mongkos (00��55.44'N110��32.34'E); H. H. Tan et al., 12 June 1999. The following non-type lots are all from the type locality, but with different collectors and dates of collection, as indicated. ZRC 47123, 5 ex., 24.9-32.0 mm SL; H. H Tan et al., 14 Jan. 1996. ZRC 41212, 9 ex., 19.9-37.9 mm SL; H. H Tan et al.,19 Feb. 1997. ZRC 47112, 12 ex., 13.6-37.0 mm SL; H. H. Tan et al., 29 Oct. 1997. ZRC 47113, 9 ex., 28.8-38.8 mm SL (site 1, sample 1); ZRC 47114, 16 ex., 14.5-35.0 mm SL (site 1, sample 2); ZRC 47115, 64 ex., 13.3-37.1 mm SL (site 1, sample 3); Honours 98/99 Fish Group, 24 June 1998. ZRC 47116, 31 ex., 11.0-37.6 mm SL (site 2, sample2); ZRC 47117, 30 ex., 20.8-37.8 mm SL (site 2, sample 3); Honours 98/99 Fish Group, 25 June 1998. ZRC 47118, 10 ex., 14.7-33.2 mm SL (site 3, sample 2); Honours 98/99 Fish Group, 26 June 1998. ZRC 43621, 20 ex., 10.3-38.2 mm SL; H. H Tan & W. K. Goh, 6 Feb. 1999. ZRC 47119, 76 ex., 16.1-40.2 mm SL; H. H. Tan et al., 10 June 1999. ZRC 47189, 10 ex., 24.4-39.5 mm SL; native collectors, 22 June 2002. Diagnosis.- Gastromyzon farragus differs from its congeners in having the following unique combination of characters: body dark brown, dorsum with 9-10 thin cream bars, side with spots and blotches, head dorsum dark brown with fine cream spots; caudal fin red in life; sublacrymal groove just visible when viewed from side; absence of a secondary rostrum; absence of a postoral pouch; gill slit angular, subopercular groove present and continuous to pectoral fin origin; a rounded snout when viewed dorsally; abdomen without scales; 52-55 scales in lateral line; pelvic fin not overlapping anal fin origin, adpressed dorsal fin not overlapping anal fin origin. Maximum size: 40.2 mm SL (ZRC 47119). Description.-General body shape and appearance as in Figs. 5-6. Meristic and morphometric data appear in Table 1. Head rounded in dorsal profile, relatively short (26.7-28.3 % SL) and wide (20.1-21.8 % SL, 73.0-80.4 % HL), head relatively flattened (head depth 13.1-14.3 % SL, 49.0-51.1 % HL); snout elongated (snout length 57.5-61.8 % HL), tubercles present over entire head, concentrated on anterior part of snout; sublacrymal groove present, just visible from side of snout; gill slit strongly angular, subopercular groove pronounced and continuous to origin of pectoral fin base; postoral pouch absent; belly scales absent; posterior part of pectoral fin overlapping anterior part of pelvic fin; anteriormost pectoral and pelvic-fin rays with dorsal serrae; dorsal fin situated about mid body (predorsal length 56.0-58.6 % SL), adpressed dorsal fin not overlapping level of anal fin origin; deepest part of body at dorsal fin origin (body depth at dorsal fin origin 19.2-20.2 % SL); anus situated just beyond posterior base of fused pelvic fins; caudal peduncle relatively deep (10.3-11.5 % SL) and relatively long (9.3-11.1 % SL). Pigmentation and life coloration. See Fig. 5. Body dark brown; dorsum with 9-10 thin cream bars; side with fine cream spots; ventrum cream; a tiny gold spot on posterior edge of every body scale. Head dorsum dark brown, with fine cream spots. Eye with golden iris. Dorsal fin yellowish brown, with 2 black bars, subdistal bar most distinct, hyaline interradial membrane and margin, antero-basal black spot present. Caudal-fin base yellowish, fin light brown with 1 subdistal thick black bar suffused with red, hyaline interradial membrane and yellowish margin. Anal-fin base black, fin light brown with 2 thin black bars, and hyaline margin. Pectoral and pelvic fins dark brown, with 2-3 rows of cream spots, and hyaline margins. Pelvic axillary flap brown with 5-6 cream spots. Color in alcohol.-See Fig. 6. Body dark brown or black; dorsum with 9-10 faint thin cream bars; side with indistinct cream spots; ventrum cream. Head dorsum dark brown, with fine cream spots. Dorsal fin cream, with 2 black bars, subdistal bar most distinct, hyaline interradial membrane and margin, antero-basal black spot present. Caudal fin base cream, fin cream with 1 subdistal thick black bar, hyaline interradial membrane and margin. Anal-fin base black, fin cream with 2 thin black bars, hyaline margin. Pectoral fin dark brown with 2-3 broad rows of cream spots, hyaline margin. Suprapelvic posterior part over pelvic fin base flap light brown. Pelvic fin cream, with dark brown base, and thick hyaline margin. Juveniles with interrupted cream bars on posterior half of grey body; dorsum uniform; caudal fin base with 1 black bar. Remarks.- Gastromyzon farragus can be further differentiated from G. ocellatus by having the head dorsum with fine cream spots only (vs. cream spots and blotches); anterior half of body with spots (vs. bars); 4-5 cream bars anterior to dorsal fin origin (vs. 3 bars); sublacrymal groove just visible from side (vs. not visible); fewer lateral-line scales (52-55, vs. 56-61); narrower head width (20.1-21.8, vs. 23.3-27.2 % SL; 73.0-80.4, vs. 90.0-95.9 % HL). Distribution.- Gastromyzon farragus is currently only known from hill streams of the Sadong River basin in southern Sarawak (Fig. 7). Etymology.-The species name is from the Latin farrago, meaning mixture. This is in allusion to the presence of both bars (on the dorsum) and spots (on the lateral) on body. Used as an adjective., Published as part of H. H. Tan & C. U. M. Leh, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from southern Sarawak., pp. 1-19 in Zootaxa 1126 on pages 15-18

Gastromyzon crenastus, new species Figs. 3-4 Material examined: BORNEO: SARAWAK (Sadong River basin): HOLOTYPE: SM uncatalogued, 28.1 mm SL; Serian, Sungai Kuhas, 6.9 km from Tebelu Tebakang turnoff, 5.8 km inside right side road (01º09’10.0”N110º29’22.7”E); H. H. Tan et al., 5 Sept. 1995. PARATYPES: SM uncatalogued, 9 ex., 16.9-24.7 mm SL; ZRC 39416, 10 ex., 16.7-28.4 mm SL; CMK 11958, 4 ex., 25.1-28.0 mm SL; preceding lots collected with holotype. The following paratype lots are also from the type locality, but with different collectors and dates of collection, as indicated. ZRC 39831, 7 ex., 20.3-29.7 mm SL; H. H Tan et al., 14 Jan. 1996. ZRC 47075, 6 ex., 18.9-22.4 mm SL; H. H. Tan et al., 19 Feb. 1997. ZRC 47076, 24 ex., 18.2-26.8 mm SL; Honours 98/99 Fish Group, 23 June 1998. NON-TYPE MATERIAL: ZRC 47084, 1 ex., 29.0 mm SL; Sarawak: Tebedu, Sungai Ahi, on road towards Mongkos (00°55.44'N110°32.34'E); H. H. Tan et al., 12 June 1999. The following non-type lots are all from the type locality, but with different collectors and dates of collection, as indicated. ZRC 41213, 16 ex., 18.0-22.2 mm SL; H. H Tan et al., 19 Feb. 1997. ZRC 47077, 2 ex., 19.8-27.8 mm SL; H. H. Tan et al, 29 Oct. 1997. ZRC 47078, 5 ex., 21.5-24.3 mm SL (site 1, sample 2); ZRC 47079, 6 ex., 18.1-26.1 mm SL (site 1, sample 3); Honours 98/99 Fish Group, 24 June 1998. ZRC 47080, 2 ex., 22.7-25.4 mm SL (site 2, sample 2); ZRC 47081, 2 ex., 17.3-23.4 mm SL (site 2, sample 3); Honours 98/99 Fish Group, 25 June 1998. ZRC 47082, 2 ex., 16.6-16.9 mm SL (site 3, sample 2); Honours 98/99 Fish Group, 26 June 1998. ZRC 47083, 14 ex., 14.5-24.0 mm SL; H. H. Tan et al., 10 June 1999. ZRC 47188, 9 ex., 21.4-25.3 mm SL; native collectors, 22 June 2002. Diagnosis.- Gastromyzon crenastus differs from its congeners in having the following unique combination of characters: a black body; dorsum with 6-8 thin cream bars or spots; head black, with cream spots and blotches; sublacrymal groove visible from side; absence of a secondary rostrum; absence of a postoral pouch; absence of a subopercular groove; gill slit vertical; snout truncate when viewed dorsally; abdomen without scales; 60-65 scales in lateral line; pelvic fin not overlapping anal fin origin, adpressed dorsal fin not at level overlapping anal fin origin. Maximum size: 29.7 mm SL (ZRC 39831), the smallest known species of Gastromyzon. Description. General body shape and appearance as in Figs. 3-4. Meristic and morphometric data appear in Table 1. Head truncate in dorsal profile, relatively short (27.5-29.8 % SL) and relatively wide (21.3-24.2 % SL, 74.3-83.3 % HL); head relatively flattened (head depth 12.8-13.9 % SL, 44.3-47.6 % HL); tubercles concentrated at anterior part of snout; snout relatively long (snout length 54.1-58.2 % HL); sublacrymal groove present, distinct when viewed from side; gill slit straight and vertical; length of gill slit about same as eye diameter; subopercular groove absent; postoral pouch absent; belly scales absent; pectoral fin overlapping anterior part of pelvic fin; pelvic fin not overlapping anal fin origin; anteriormost pectoral and pelvic-fin rays with dorsal serrae; dorsal fin situated at about mid body (predorsal length 55.2-59.2 % SL), adpressed dorsal fin not extending past level of anal-fin origin; deepest part of body at dorsal-fin origin (body depth at dorsal-fin origin 16.2-18.5 % SL); anus situated just beyond posterior base of fused pelvic fins; caudal peduncle relatively deep (9.5-10.7 % SL) and relatively short (8.5-10.8 % SL). Pigmentation and life coloration.-See Fig. 3. Body black on dorsum and sides; dorsum with 6-8 thin cream bars or spots; side with bars interrupted to form spots and blotches; ventrum cream. Head dorsum black, with cream spots and blotches. Eye with golden iris. Dorsal fin light brown, with 1 thick black bar, hyaline interradial membrane and margin; antero-basal black spot present on dorsal fin. Caudal fin base black, fin rays light brown with subdistal part a large black blotch, area just before blotch with iridescent blue, upper border with red, hyaline interradial membrane and thick margin. Anal-fin rays brown, hyaline edge. Pectoral and pelvic fins brown with 1 black bar. Pelvic axillary flap black with distal cream margin. Color in alcohol.-See Fig. 4. Body black on dorsum and sides, dorsum with 6-8 thin cream bars or spots, side with bars interrupted to form spots and blotches, ventrum cream. Head dorsum black with cream spots and blotches. Dorsal fin rays light brown with 1 thick black bar, fin with hyaline interradial membrane and margin, antero-basal black spot present. Caudal fin base black, anterior part with thin crescentic black band, centre of fin with large black blotch and with thin hyaline margin, hyaline interradial membrane and margin. Anal fin black, with hyaline margin. Pectoral and pelvic fins grey with 1 black bar. Pelvic axillary flap black, with distal cream margin. Juveniles with 5-6 cream spots and blotches on black body, head plain, caudal fin base black, with faint central black bar. Remarks.- Gastromyzon crenastus can be further differentiated from other congeners of the G. ridens group by the following characters: snout truncate in dorsal profile vs. rounded in G. ridens; adpressed dorsal fin not overlapping level of anal-fin origin vs. overlapping in G. ridens; pelvic fin not overlapping anal fin origin vs. overlapping in G. ridens. Distribution.-This species is known only from the hill streams feeding the Sadong River basin in southern Sarawak (Fig. 7). Etymology.-The species name is from the Latin crena, meaning notch. This is in reference to the white blotches and bars on the dark coloured body. Used as an adjective.

Gastromyzon farragus, new species Figs. 5-6 Material examined: BORNEO: SARAWAK (Sadong River basin): HOLOTYPE: SM uncatalogued, 30.9 mm SL; Serian, Sungai Kuhas, 6.9 km after Tebelu Tebakang turnoff, 5.8 km inside right side road (01º0910.0”N110º2922.7”E); H. H Tan et al., 5 Sept. 1995. PARATYPES: SM uncatalogued, 6 ex., 17.3-22.8 mm SL; ZRC 47108, 7 ex., paratypes, 15.4-35.9 mm SL; collected with holotype. The following paratypic lots are also from the type locality, but with different collectors and dates of collection, as indicated. ZRC 47109, 6 ex., 15.3-36.1 mm SL; H. H Tan et al., 14 Jan. 1996. ZRC 47110, 6 ex., 24.0-37.1 mm SL; H. H. Tan et al., 19 Feb. 1997. ZRC 47111, 36 ex., 18.7-38.5 mm SL; Honours 98/99 Fish Group, 23 June 1998. NON-TYPE MATERIAL: ZRC 47120, 4 ex., 18.4-28.9 mm SL; Sarawak: Tebedu, Sungai Ahi, on road towards Mongkos (00º55.44'N110º32.34'E); H. H. Tan et al., 12 June 1999. The following non-type lots are all from the type locality, but with different collectors and dates of collection, as indicated. ZRC 47123, 5 ex., 24.9-32.0 mm SL; H. H Tan et al., 14 Jan. 1996. ZRC 41212, 9 ex., 19.9-37.9 mm SL; H. H Tan et al.,19 Feb. 1997. ZRC 47112, 12 ex., 13.6-37.0 mm SL; H. H. Tan et al., 29 Oct. 1997. ZRC 47113, 9 ex., 28.8-38.8 mm SL (site 1, sample 1); ZRC 47114, 16 ex., 14.5-35.0 mm SL (site 1, sample 2); ZRC 47115, 64 ex., 13.3-37.1 mm SL (site 1, sample 3); Honours 98/99 Fish Group, 24 June 1998. ZRC 47116, 31 ex., 11.0-37.6 mm SL (site 2, sample2); ZRC 47117, 30 ex., 20.8-37.8 mm SL (site 2, sample 3); Honours 98/99 Fish Group, 25 June 1998. ZRC 47118, 10 ex., 14.7-33.2 mm SL (site 3, sample 2); Honours 98/99 Fish Group, 26 June 1998. ZRC 43621, 20 ex., 10.3-38.2 mm SL; H. H Tan & W. K. Goh, 6 Feb. 1999. ZRC 47119, 76 ex., 16.1-40.2 mm SL; H. H. Tan et al., 10 June 1999. ZRC 47189, 10 ex., 24.4-39.5 mm SL; native collectors, 22 June 2002. Diagnosis.- Gastromyzon farragus differs from its congeners in having the following unique combination of characters: body dark brown, dorsum with 9-10 thin cream bars, side with spots and blotches, head dorsum dark brown with fine cream spots; caudal fin red in life; sublacrymal groove just visible when viewed from side; absence of a secondary rostrum; absence of a postoral pouch; gill slit angular, subopercular groove present and continuous to pectoral fin origin; a rounded snout when viewed dorsally; abdomen without scales; 52-55 scales in lateral line; pelvic fin not overlapping anal fin origin, adpressed dorsal fin not overlapping anal fin origin. Maximum size: 40.2 mm SL (ZRC 47119). Description.-General body shape and appearance as in Figs. 5-6. Meristic and morphometric data appear in Table 1. Head rounded in dorsal profile, relatively short (26.7-28.3 % SL) and wide (20.1-21.8 % SL, 73.0-80.4 % HL), head relatively flattened (head depth 13.1-14.3 % SL, 49.0-51.1 % HL); snout elongated (snout length 57.5-61.8 % HL), tubercles present over entire head, concentrated on anterior part of snout; sublacrymal groove present, just visible from side of snout; gill slit strongly angular, subopercular groove pronounced and continuous to origin of pectoral fin base; postoral pouch absent; belly scales absent; posterior part of pectoral fin overlapping anterior part of pelvic fin; anteriormost pectoral and pelvic-fin rays with dorsal serrae; dorsal fin situated about mid body (predorsal length 56.0-58.6 % SL), adpressed dorsal fin not overlapping level of anal fin origin; deepest part of body at dorsal fin origin (body depth at dorsal fin origin 19.2-20.2 % SL); anus situated just beyond posterior base of fused pelvic fins; caudal peduncle relatively deep (10.3-11.5 % SL) and relatively long (9.3-11.1 % SL). Pigmentation and life coloration. See Fig. 5. Body dark brown; dorsum with 9-10 thin cream bars; side with fine cream spots; ventrum cream; a tiny gold spot on posterior edge of every body scale. Head dorsum dark brown, with fine cream spots. Eye with golden iris. Dorsal fin yellowish brown, with 2 black bars, subdistal bar most distinct, hyaline interradial membrane and margin, antero-basal black spot present. Caudal-fin base yellowish, fin light brown with 1 subdistal thick black bar suffused with red, hyaline interradial membrane and yellowish margin. Anal-fin base black, fin light brown with 2 thin black bars, and hyaline margin. Pectoral and pelvic fins dark brown, with 2-3 rows of cream spots, and hyaline margins. Pelvic axillary flap brown with 5-6 cream spots. Color in alcohol.-See Fig. 6. Body dark brown or black; dorsum with 9-10 faint thin cream bars; side with indistinct cream spots; ventrum cream. Head dorsum dark brown, with fine cream spots. Dorsal fin cream, with 2 black bars, subdistal bar most distinct, hyaline interradial membrane and margin, antero-basal black spot present. Caudal fin base cream, fin cream with 1 subdistal thick black bar, hyaline interradial membrane and margin. Anal-fin base black, fin cream with 2 thin black bars, hyaline margin. Pectoral fin dark brown with 2-3 broad rows of cream spots, hyaline margin. Suprapelvic posterior part over pelvic fin base flap light brown. Pelvic fin cream, with dark brown base, and thick hyaline margin. Juveniles with interrupted cream bars on posterior half of grey body; dorsum uniform; caudal fin base with 1 black bar. Remarks.- Gastromyzon farragus can be further differentiated from G. ocellatus by having the head dorsum with fine cream spots only (vs. cream spots and blotches); anterior half of body with spots (vs. bars); 4-5 cream bars anterior to dorsal fin origin (vs. 3 bars); sublacrymal groove just visible from side (vs. not visible); fewer lateral-line scales (52-55, vs. 56-61); narrower head width (20.1-21.8, vs. 23.3-27.2 % SL; 73.0-80.4, vs. 90.0-95.9 % HL). Distribution.- Gastromyzon farragus is currently only known from hill streams of the Sadong River basin in southern Sarawak (Fig. 7). Etymology.-The species name is from the Latin farrago, meaning mixture. This is in allusion to the presence of both bars (on the dorsum) and spots (on the lateral) on body. Used as an adjective.

[[Gastromyzon]] The genus Gastromyzon, which is endemic to Borneo, exhibits extreme external morphological adaptations for life in torrential waters. Obligate bottom dwellers, the included species have lost the ability to hover or swim in the mid-water column, and as a consequence have evolved new modes of locomotion, which involve creeping and crawling over submerged rocks. Locomotion in the genus has been studied by Wickler (1971) using aquarium stocks of G. ctenocephalus (misidentified as G. borneensis). The horizontally oriented pectoral fins, fused pelvic fins, and depressed head and body collectively form a suction cup, which enables the fish to adhere to the submerged rocky substrate of fast-flowing stream habitats. In addition, the genus is characterized by greater numbers of pectoral and pelvic-fin rays, these numbering 20-30 and 16-24 branched rays, respectively. This compares to the other 250 or more species of cyprinoids in the Sunda Islands, in which the number of branched pectoral rays usually does not exceed 17 and the number of branched pelvic rays does not exceed 12 (with the latter usually no more than 8; Inger & Chin, 1961). Unicellular horny projections, or unculi, on the ventral surfaces of the fish apparently also serve to increase adhesion on smooth rock surfaces (Roberts, 1982a, 1982b, 1989). The morphological adaptations described above are shared by the closely related balitorid genera Hypergastromyzon and Neogastromyzon, which are also endemic to Borneo. During the course of a taxonomic revision of Gastromyzon, collaborations were made with regional scientists to facilitate research and collections, which resulted in discovery of the three new species described in this paper., Published as part of H. H. Tan & C. U. M. Leh, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from southern Sarawak., pp. 1-19 in Zootaxa 1126 on pages 1-2

[[Gastromyzon]] The genus Gastromyzon, a unique group of fishes endemic to the island of Borneo, exhibits extreme morphological adaptations for life in torrential waters. The included species, which are obligate bottom dwellers, are poor swimmers that have lost the ability to hover or swim in mid-water. As a consequence, the genus has evolved new modes of locomotion, which involve creeping and crawling along the bottom. Balitorid locomotion had been studied by Wickler (1971) using aquarium stocks of G. ctenocephalus (misidentified as G. borneensis). He found that the horizontally oriented pectoral fins, fused pelvic fins, and depressed head and body collectively form a suction cup that enables the fish to adhere to the submerged rock substrate of fast flowing streams. The genera Gastromyzon, Hypergastromyzon and Neogastromyzon are characterized by fused pelvic fins; and a higher number of branched pectoral and pelvic-fin rays (numbering 20-30 and 16-24 respectively) than are found in the other 250 or more species of cyprinoids in the Sunda Islands, in which the number of branched pectoral rays does not usually exceed 17 and branched pelvic rays does not exceed 12 (and is usually not more than 8; Inger & Chin, 1961). Unicellular horny projections, or unculi, on the ventral surfaces of the fish’s body apparently also serve to increase adhesion on smooth rocky surfaces (Roberts, 1982a, 1982b, 1989).

Gastromyzon pariclavis group Diagnosis. This species group is defined by the following suite of characters: an elongated snout, with snout length 50.0-73.1 % HL; a rounded and protruding head when viewed dorsally; an angular gill slit; a distinct subopercular groove, which is continuous with the pectoral fin origin; caudal fin appearing to have the distal top and bottom rays elongated when the fin is not stretched out; absence of secondary rostrum; absence of postoral pouch; absence of scales on abdomen; and coloured fins in life. Males and females of G. embalohensis have red and yellow fins, respectively (Rachmatika, 1998). In G. venustus, both sexes have reddish fins., Published as part of H. H. Tan & Z. H. Sulaiman, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from the Temburong River basin, Brunei Darussalam, Borneo., pp. 1-19 in Zootaxa 1117 on page 13

Gastromyzon scitulus, new species Figs. 1-2 Material examined: BORNEO: SARAWAK (Sadong River basin). HOLOTYPE: SM uncatalogued, 25.1 mm SL; Serian, Sungai Kuhas, 6.9 km from Tebelu Tebakang turnoff, 5.8 km inside right side road (01º0910.0”N110º2922.7”E); H. H. Tan et al., 5 Sept. 1995. PARATYPES: ZRC 47035, 5 ex., 18.0-23.5 mm SL; CMK 11959, 3 ex., 18.7-23.6 mm SL; same collection data as holotype. The following paratypic lots are also from the type locality, but with different collectors and dates of collection, as indicated. ZRC 47036, 3 ex., 23.3-26.1 mm SL; H. H Tan et al., 14 Jan. 1996. ZRC 47037, 6 ex., 18.4- 26.7 mm SL; H. H. Tan et al., 19 Feb. 1997. SM uncatalogued, 9 ex., 16.7-25.0 mm SL; ZRC 47038, 9 ex., 15.2-29.7 mm SL; Honours 98/99 Fish Group, 23 June 1998. NON-TYPE MATERIAL: ZRC 47046, 4 ex., 23.2-25.0 mm SL; Sarawak: Tebedu, Sungai Ahi, on road towards Mongkos (00º55.44'N110º32.34'E); H. H. Tan et al., 12 June 1999. The following non-type lots are from the type locality, but with different collectors and dates of collection, as indicated. ZRC 41214, 20 ex., 17.0-30.9 mm SL; H. H Tan et al., 19 Feb. 1997. ZRC 43620, 2 ex., 18.1-27.8 mm SL; H. H Tan & W. K. Goh, 6 Feb. 1999. ZRC 47039, 5 ex., 16.6-25.0 mm SL; H. H. Tan et al., 29 Oct. 1997. ZRC 47040, 21 ex., 12.0-23.6 mm SL (site 1, sample 2); ZRC 47041, 4 ex., 12.3-26.8 mm SL (site 1, sample 3); Honours 98/99 Fish Group, 24 June 1998. ZRC 47042, 6 ex., 17.4-28.2 mm SL (site 2, sample 2); ZRC 47043, 14 ex., 15.6-20.5 mm SL (site 2, sample 3); Honours 98/99 Fish Group, 25 June 1998. ZRC 47044, 13 ex., 11.5-21.3 mm SL (site 3, sample 2); Honours 98/99 Fish Group, 26 June 1998. ZRC 47045, 57 ex., 17.2-31.3 mm SL; H. H. Tan et al., 10 June 1999. ZRC 47190, 23 ex., 16.6-30.6 mm SL; native collectors, 22 June 2002. Diagnosis. Gastromyzon scitulus differs from its congeners in having the following unique combination of characters: gill slit angular; subopercular groove present and continuous to pectoral fin origin; body black with numerous evenly spaced small light brown spots, head dorsum black with numerous cream spots, pectoral and pelvic fins with cream spots; caudal fin with iridescent blue streaks in life; sublacrymal groove present; snout strongly sloping from eye to snout, snout rounded when viewed dorsally; absence of a secondary rostrum; absence of a postoral pouch; abdomen without scales; 57-58 scales in lateral line; pelvic fin just reaching anal fin origin, adpressed dorsal fin just reaching level of anal fin origin. Maximum size: 31.3 mm SL (ZRC 47045). Description. General body shape and appearance as in Figs. 1-2. Meristic and morphometric data appear in Table 1. Head rounded in dorsal profile; short (27.6-28.8 % SL) and relatively wide (20.1-21.8 % SL, 69.7-77.3 % HL), head relatively flattened (head depth 13.9-14.9 % SL, 48.5-54.2 % HL), tubercles over entire head; snout relatively long (snout length 53.0-62.5 % HL); sublacrymal groove present, not visible from side; gill slit angular; subopercular groove present and continuous to pectoral fin origin; postoral pouch absent; belly scales absent; posterior part of pectoral fin overlapping anterior fourth of pelvic fin; pelvic fin just touching anal fin origin; serrae on anterior rays of pectoral and pelvic fins; dorsal fin situated about mid body (predorsal length 55.2-58.2 % SL), adpressed dorsal fin just touching level of anal-fin origin; deepest part of body at dorsal-fin origin (body depth at dorsal-fin origin 19.0-20.9 % SL); anus situated just beyond posterior margin of pelvic fin; caudal peduncle short (8.4-10.5 % SL) and relatively narrow (9.9-10.5 % SL). Pigmentation and life coloration.-See Fig. 1. Body dark brown, dorsum and sides with numerous evenly spaced small light brown spots; ventrum cream. Head dorsum dark brown, with numerous cream spots. Eye with golden iris. Dorsal fin base with 3 cream spots. Dorsal fin light brown, with 3 black bars, the subdistal bar most distinct; proximal part of dorsal fin yellowish, with hyaline fin margin and interradial membrane; anterobasal black spot present. Caudal fin base yellowish, fin rays brown, the central portion black and shaped in a figure 8; caudal streaked with iridescent blue on interradial membranes, the top distal half of rays with thick hyaline edge, middle with thin hyaline edge, and bottom half of rays with thin reddish edge. Anal fin brown with 2 black bars and a hyaline edge. Pectoral and pelvic fins dark brown with 2-3 rows of light brown spots and a light brown edge. Pelvic axillary flap brown with 4-5 cream spots. Color in alcohol.-See Fig. 2. Body dark brown or black, the dorsum and sides with numerous faint, evenly spaced small cream spots; ventrum cream. Head dorsum dark brown or black, with numerous cream spots. Dorsal fin base with 3 cream spots. Dorsal fin light brown, with 3 black bars, the subdistal bar most distinct; fin with hyaline interradial membrane and margin; antero-basal black spot present. Caudal fin base grey, fin rays cream, central portion black with figure 8 shape, thick hyaline edge. Anal fin cream, with 2 black bars and hyaline edge. Pectoral and pelvic fins dark brown with 2-3 rows of light brown spots and brown edge. Pelvic axillary flap brown, with faint spots. Remarks.- Gastromyzon scitulus can be further differentiated from G. ctenocephalus by the following characters: dorsal fin without iridescent blue spots (vs. spots present); dorsal fin base with 3 cream spots (vs. 4-5 spots); pelvic axillary flap with 4-5 spots (vs. 7 or more spots); fewer pectoral-fin rays (25-26, mode 25, vs. 27-29, mode 28); fewer pelvic-fin rays (17, vs. 18-19, mode 19); fewer lateral-line scales (57-58, mode 58, vs. 59- 62, mode 60); fewer predorsal scales (24-27, mode 25, vs. 30-33, mode 30); fewer caudalpeduncle scales (5.1.5, vs. 6-7.1.6-7); narrower head width (20.1-21.8, vs. 21.5-27.0 % SL); greater interorbital width (12.3-13.4, vs. 10.7-12.5 % SL). Distribution.- Gastromyzon scitulus is currently only known from the Sadong River basin, in southern Sarawak (Fig. 7). Etymology -The species name is from the Latin scitulus, meaning beautiful, elegant. This is in allusion to the pretty body pattern and coloration in life. Used as an adjective. Field notes.-The type locality, Sungai Kuhas (Fig. 8), is an unshaded hill stream running next to a Bidayuh village (Kampung Lanchang). This village is surrounded by pepper and cocoa plantations, with scrub and secondary vegetation and with some remnant hill forest. The Gastromyzon species are most common above, below, and within the riffle zone, about 1-3 metres wide in shallow running water (pH 7.0) amongst the submerged rocks. Syntopic balitorid species present were Gastromyzon crenastus, G. farragus, Glaniopsis sp., Homaloptera weberi and Nemacheilus saravacensis. Other syntopic species include: Barbonymus collingwoodi, Esomus metallicus [introduced], Hampala macrolepidota, Paracrossocheilus vittata, Puntius banksi, P. kuchingensis, P. orphoides, P. sealei, Rasbora caudimaculata, R. sarawakensis (Cyprinidae), Silurichthys marmoratus (Siluridae), Glyptothorax major (Sisoridae), Clarias leiacanthus (Clariidae), Dermogenys collettei, Hemirhamphodon keukenthali (Hemiramphidae), Betta taeniata (Osphronemidae), Channa gachua, C. lucius (Channidae), and Macrognathus maculatus (Mastacembelidae). Short-term ecological observations were made during a week-long fourth year Honours field course conducted in June 1998. From preliminary surveys conducted earlier, G. farragus was the most common species (65% of total Gastromyzon specimens) and G. crenastus the least common (10% of specimens); which was substantiated by this survey (based on 298 specimens). All three species preferred larger rocks and areas with fast water current. None was obtained from the small rock area with slow water current. However, none was obtained from areas with large rocks and slow water current. Perhaps the larger rocks provide more conducive spots for the fish to reside. Where the water current is strong, smaller sized substratum is usually lacking due to the currents washing these away. There appears to be no difference in gut length between the three species (gut length 248-353 % SL for G. crenastus [n=9], 228-350 % SL for G. farragus [n=12], 234-342 % SL for G. scitulus [n=9]). However, the gut length is consistent with their herbivorous habits, ranging from 248-353 % of standard length (Clayton, 1993). The guts were dissected and the contents of the stomach and foregut examined with a stereoscope. Much of the gut contents was mush and probably consisted of algal and detrital matter. When parts of the gut content were fixed in 75 % alcohol, a greenish colour was leached out, suggesting the presence of chlorophyll, which indicates algal or plant origins.

Gastromyzon crenastus, new species Figs. 3-4 Material examined: BORNEO: SARAWAK (Sadong River basin): HOLOTYPE: SM uncatalogued, 28.1 mm SL; Serian, Sungai Kuhas, 6.9 km from Tebelu Tebakang turnoff, 5.8 km inside right side road (01��09���10.0���N110��29���22.7���E); H. H. Tan et al., 5 Sept. 1995. PARATYPES: SM uncatalogued, 9 ex., 16.9-24.7 mm SL; ZRC 39416, 10 ex., 16.7-28.4 mm SL; CMK 11958, 4 ex., 25.1-28.0 mm SL; preceding lots collected with holotype. The following paratype lots are also from the type locality, but with different collectors and dates of collection, as indicated. ZRC 39831, 7 ex., 20.3-29.7 mm SL; H. H Tan et al., 14 Jan. 1996. ZRC 47075, 6 ex., 18.9-22.4 mm SL; H. H. Tan et al., 19 Feb. 1997. ZRC 47076, 24 ex., 18.2-26.8 mm SL; Honours 98/99 Fish Group, 23 June 1998. NON-TYPE MATERIAL: ZRC 47084, 1 ex., 29.0 mm SL; Sarawak: Tebedu, Sungai Ahi, on road towards Mongkos (00��55.44'N110��32.34'E); H. H. Tan et al., 12 June 1999. The following non-type lots are all from the type locality, but with different collectors and dates of collection, as indicated. ZRC 41213, 16 ex., 18.0-22.2 mm SL; H. H Tan et al., 19 Feb. 1997. ZRC 47077, 2 ex., 19.8-27.8 mm SL; H. H. Tan et al, 29 Oct. 1997. ZRC 47078, 5 ex., 21.5-24.3 mm SL (site 1, sample 2); ZRC 47079, 6 ex., 18.1-26.1 mm SL (site 1, sample 3); Honours 98/99 Fish Group, 24 June 1998. ZRC 47080, 2 ex., 22.7-25.4 mm SL (site 2, sample 2); ZRC 47081, 2 ex., 17.3-23.4 mm SL (site 2, sample 3); Honours 98/99 Fish Group, 25 June 1998. ZRC 47082, 2 ex., 16.6-16.9 mm SL (site 3, sample 2); Honours 98/99 Fish Group, 26 June 1998. ZRC 47083, 14 ex., 14.5-24.0 mm SL; H. H. Tan et al., 10 June 1999. ZRC 47188, 9 ex., 21.4-25.3 mm SL; native collectors, 22 June 2002. Diagnosis.- Gastromyzon crenastus differs from its congeners in having the following unique combination of characters: a black body; dorsum with 6-8 thin cream bars or spots; head black, with cream spots and blotches; sublacrymal groove visible from side; absence of a secondary rostrum; absence of a postoral pouch; absence of a subopercular groove; gill slit vertical; snout truncate when viewed dorsally; abdomen without scales; 60-65 scales in lateral line; pelvic fin not overlapping anal fin origin, adpressed dorsal fin not at level overlapping anal fin origin. Maximum size: 29.7 mm SL (ZRC 39831), the smallest known species of Gastromyzon. Description. General body shape and appearance as in Figs. 3-4. Meristic and morphometric data appear in Table 1. Head truncate in dorsal profile, relatively short (27.5-29.8 % SL) and relatively wide (21.3-24.2 % SL, 74.3-83.3 % HL); head relatively flattened (head depth 12.8-13.9 % SL, 44.3-47.6 % HL); tubercles concentrated at anterior part of snout; snout relatively long (snout length 54.1-58.2 % HL); sublacrymal groove present, distinct when viewed from side; gill slit straight and vertical; length of gill slit about same as eye diameter; subopercular groove absent; postoral pouch absent; belly scales absent; pectoral fin overlapping anterior part of pelvic fin; pelvic fin not overlapping anal fin origin; anteriormost pectoral and pelvic-fin rays with dorsal serrae; dorsal fin situated at about mid body (predorsal length 55.2-59.2 % SL), adpressed dorsal fin not extending past level of anal-fin origin; deepest part of body at dorsal-fin origin (body depth at dorsal-fin origin 16.2-18.5 % SL); anus situated just beyond posterior base of fused pelvic fins; caudal peduncle relatively deep (9.5-10.7 % SL) and relatively short (8.5-10.8 % SL). Pigmentation and life coloration.-See Fig. 3. Body black on dorsum and sides; dorsum with 6-8 thin cream bars or spots; side with bars interrupted to form spots and blotches; ventrum cream. Head dorsum black, with cream spots and blotches. Eye with golden iris. Dorsal fin light brown, with 1 thick black bar, hyaline interradial membrane and margin; antero-basal black spot present on dorsal fin. Caudal fin base black, fin rays light brown with subdistal part a large black blotch, area just before blotch with iridescent blue, upper border with red, hyaline interradial membrane and thick margin. Anal-fin rays brown, hyaline edge. Pectoral and pelvic fins brown with 1 black bar. Pelvic axillary flap black with distal cream margin. Color in alcohol.-See Fig. 4. Body black on dorsum and sides, dorsum with 6-8 thin cream bars or spots, side with bars interrupted to form spots and blotches, ventrum cream. Head dorsum black with cream spots and blotches. Dorsal fin rays light brown with 1 thick black bar, fin with hyaline interradial membrane and margin, antero-basal black spot present. Caudal fin base black, anterior part with thin crescentic black band, centre of fin with large black blotch and with thin hyaline margin, hyaline interradial membrane and margin. Anal fin black, with hyaline margin. Pectoral and pelvic fins grey with 1 black bar. Pelvic axillary flap black, with distal cream margin. Juveniles with 5-6 cream spots and blotches on black body, head plain, caudal fin base black, with faint central black bar. Remarks.- Gastromyzon crenastus can be further differentiated from other congeners of the G. ridens group by the following characters: snout truncate in dorsal profile vs. rounded in G. ridens; adpressed dorsal fin not overlapping level of anal-fin origin vs. overlapping in G. ridens; pelvic fin not overlapping anal fin origin vs. overlapping in G. ridens. Distribution.-This species is known only from the hill streams feeding the Sadong River basin in southern Sarawak (Fig. 7). Etymology.-The species name is from the Latin crena, meaning notch. This is in reference to the white blotches and bars on the dark coloured body. Used as an adjective., Published as part of H. H. Tan & C. U. M. Leh, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from southern Sarawak., pp. 1-19 in Zootaxa 1126 on pages 9-13

Gastromyzon cranbrooki, new species Figs. 1-2 Gastromyzon borneensis (non G��nther) - Cranbrook & Edwards, 1994: 327; Choy & Chin, 1994: 761; Doi, 1997: 19 (list; in part). Gastromyzon fasciatus (non Inger & Chin) - Choy & Chin, 1994: 762; Kottelat & Lim, 1995: 235 (part). Material examined: BRUNEI DARUSSALAM (Temburong district, Temburong River basin): HOLOTYPE: UBD uncatalogued, 48.2 mm SL; Sungai Belalong, in front and near to Kuala Belalong Field Studies Centre (04��32'50.4"N115��09'27.6"E [80 m asl]); H. H. Tan & K. K. P. Lim, 4-7 Oct 2001. PARATYPES: UBD uncatalogued, 26 ex., 20.0-45.0 mm SL; ZRC 47003, 26 ex., 19.9-53.5 mm SL; same locality as holotype. ZRC 38757, 12 ex., 19.7-61.4 mm SL; Temburong River basin: Sungai Belalong at Kuala Belalong; K. K. P. Lim et al., 14-17 Jun 1995. CMK 11553, 2 ex., 45.2-47.7 mm SL; Temburong River basin: Sungai Temburong, about 1 km downstream of Kuala Belalong; K. K. P. Lim et al., 16 Jun 1995. NON-TYPE MATERIAL: Brunei Darussalam (Temburong district: Temburong River basin): UBD-SC/92/7/F6, 4 ex., 17.9-52.8 mm SL; Sungai Belalong, Kuala Belalong Field Study Centre; S. Choy, 27 Jul 1992. UBD-SC/91/8/3, 1 ex., 75.5 mm SL; Sungai Belalong, upper Sungai Babi, past HP171; S. Choy & S. Nyawa, 7 Aug 1991. UBD-SC/92/6/2, 3 ex., 38.7-52.0 mm SL; Sungai Belalong, near Kuala Belalong Field Study Centre; S. Choy, 28 Jun 1992. UBD uncatalogued, 4 ex., 45.7-58.1 mm SL; Sungai Belalong, opposite Kuala Belalong Field Study Centre intake pipe; S. Choy, 27 Jul 1992. UBD-SC/92/7/1, 3 ex., 40.5-42.6 mm SL; Sungai Belalong, near intake pipe; A. K. Zainal & Awg. Moss, 27 Jul 1992. UBD-SC/92/8/7, 6 ex., 39.9-59.2 mm SL; Sungai Belalong near Kuala Belalong Field Study Centre, near water intake pipe; S. Choy, Dec 1991. UBD-B-11, 11 ex., 14.6- 54.6 mm SL; Sungai Belalong at Kuala Belalong; K. K. P. Lim et al., 14-17 Jun 1995. ZRC 31803, 1 ex., 46.7 mm SL; Sungai Belalong near Kuala Belalong Field Study Centre; S. C. Choy, 24 Jul 1992. ZRC 47004, 3 ex., 35.0-54.1 mm SL; Belalong River basin; Sungai Enkabang, about 15 minutes upstream of Kuala Belalong Field Studies Centre (04��32'13.5"N115��09'35.0"E [100 m asl]); H. H. Tan & K. K. P. Lim, 5 Oct 2001. ZRC 47005, 1 ex., 51.3 mm SL; Belalong River basin; Sungai Belalong at mouth of Sungai Enkabang (04��32'13.5"N115��09'35.0"E [100 m asl]); H. H. Tan et al., 6 Oct 2001. ZRC 47006, 5 ex., 39.4-52.2 mm SL; Belalong River basin; Sungai Belalong at mouth of Sungai Esu (04��32'17.9"N115��09'35.2"E); H. H. Tan et al., 6 Oct 2001. ZRC 47007, 1 ex., 48.7 mm SL; Sungai Temburong, just upstream of confluence of Sungai Temburong and Sungai Belalong; H. H. Tan et al., 5 Oct 2001. ZRC 47008, 2 ex., 33.5-57.5 mm SL; Belalong River basin; Sungai Engkiang, about 40 minutes upstream of Kuala Belalong Field Studies Centre (about 3-4 km upstream) (04��29'08.7"N115��08'43.4"E [120 m asl]); H. H. Tan & K. K. P. Lim, 8 Oct 2001. Diagnosis. Gastromyzon cranbrooki differs from its congeners in having the following unique combination of characters: presence of distinct secondary rostrum; presence of complete postoral pouch; body brown, with 9-10 grey bars, head dorsum dark brown, with thin grey reticulate pattern; absence of subopercular groove; gill slit vertical; presence of sublacrymal groove; snout truncate when viewed dorsally; abdomen without scales; 56-60 scales in lateral line; pelvic fin not overlapping anal fin origin, adpressed dorsal fin falling short of level of anal fin origin. Maximum size: 75.5 mm SL (UBD-SC/91/8/3). Description. General body shape and appearance as in Figs. 1-2. Meristic and morphometric data appear in Table 1. Head truncate when viewed in dorsal view, relatively short (26.2-29.6 % SL) and wide (26.2-30.4 % SL, 88.5-106.7 % HL), head relatively flattened (head depth 13.5-14.9 % SL, 47.4-52.4 % HL). Tubercles concentrated on anterior part of snout below secondary rostrum. Snout relatively long (65.7-70.3 % HL), with broadly rounded secondary rostrum; mature males with secondary rostrum longer than primary rostrum. Sublacrymal groove present, not visible from side. Gill slit vertical, its length less than eye diameter. Subopercular groove absent. Postoral pouch complete. No scales on belly. Pectoral and pelvic fins with serrae on anteriormost rays. Posterior part of pectoral fin just reaching anterior part of pelvic fin. Pelvic fin not reaching anal fin origin. Dorsal fin situated at about mid body (predorsal length 53.8-58.8 % SL), adpressed dorsal fin falling short of level of anal-fin origin. Deepest part of body at dorsal-fin origin (body depth at dorsal-fin origin 17.3-20.8 % SL). Anus between posterior base of fused pelvic fins and anal fin origin. Some specimens with tubercles on posterior part of lower half of body. Caudal peduncle relatively deep (8.6-9.6 % SL) and short (7.6- 10.4 % SL). Body pigmentation and life coloration- See Fig. 1. This species was first depicted by Cranbrook & Edwards (1994: 327). Body dark brown on dorsum and sides, body with 9- 10 grey bars on side of body that are continuous across dorsum and connect with bars on opposite side; a white spot on posterior edge of every body scale; ventrum cream. Head dorsum dark brown with thin grey reticulate pattern. Eye with golden iris. Dorsal fin grey on lowermost two-thirds of rays, the interradial membranes and margin of fin hyaline. A basal black spot present on anterior part of dorsal fin. Caudal-fin base black, the fin with 4-5 black bars, fin with hyaline edge and with golden sheen in the middle section of fin. Anal-fin rays black on lowermost two-thirds; margin of fin broadly hyaline, with golden sheen. Pectoral-fin rays dark brown with 2-3 faint grey bands and hyaline margin. Pelvic axillary flap brown with yellowish margin. Pelvic-fin dark brown with 2 faint grey bands, thin hyaline margin on anterior part of fin; a thicker hyaline margin on posterior part of fin. Colour in alcohol. See Fig. 2. Body black on dorsum and sides, with 9-10 grey bars extending from one side to the other side across dorsum; ventrum cream. Head dorsum black with faint thin grey reticulate pattern. Dorsal-fin rays grey on lowermost two-thirds, the interradial membranes and margin of fin hyaline. A basal black spot present on anterior part of dorsal fin. Caudal fin base black, the fin rays grey with 4-5 black bars across fin, and with interradial membranes and posterior margin hyaline. Anal-fin rays grey, with 2 black bars, and with a wide hyaline area on posterior margin of fin. Pectoral fin black, with 2-3 faint grey bands, and with a very thin hyaline posterior margin. Pelvic axillary flap black, with a thin grey margin. Pelvic fin black, with 2 faint grey bands, a very thin hyaline margin anteriorly, and a thick hyaline margin posteriorly. Juveniles with up to 11 cream bars on body, head with faint cream reticulate pattern, caudal fin with 2 black bars. Distribution. Gastromyzon cranbrooki is currently known only from the Temburong River basin, Brunei Darussalam (Fig. 7). Remarks. Gastromyzon cranbrooki may be readily confused with G. borneensis, which also possesses a barred body and a secondary rostrum. In addition to characters included in the Diagnosis, G. cranbrooki can be further differentiated from the other congeners of the G. borneensis group by the following characters: presence of a secondary rostrum (vs. absence in G. monticola and G. ornaticauda); head truncate in dorsal view (vs. rounded in G. monticola); pelvic fin not overlapping anal fin origin (vs. overlapping in G. ornaticauda); pectoral fin length less than in G. ornaticauda (37.4-41.5, vs. 41.4-43.7 % SL); greater head width than in G. ornaticauda (26.2-30.4, vs. 21.7-25.9 % SL); greater orbit diameter than in G. monticola (3.7-4.5, vs. 2.9-3.5 % SL). Etymology. Named for the Earl of Cranbrook, in recognition of his contributions to the study of biodiversity in Southeast Asia. Field notes. Gastromyzon cranbrooki is the most common Gastromyzon species in the riffle zones of Sungai Belalong. Most specimens were obtained from a rocky area about 15 metres wide, just 20 metres upstream of the Kuala Belalong Field Studies Centre (Fig. 8), in shallow flowing water less than 50 cm deep, and with the pH 6.6. The substrate consists of a mix of small rocks and gravel of quartz, basalt and shale origin. Syntopic species include three other Gastromyzon (G. aeroides, G. punctulatus, G. venustus) and two additional balitorid species (Parhomaloptera microstoma and Neogastromyzon sp.). Other syntopic species include Barbonymus collingwoodii, Hampala bimaculata, Lobocheilos cf. bo, Nematabramis steindachneri, Paracrossocheilus acerus, Rasbora agyrotaenia, Tor tambra (Cyprinidae), Glyptothorax major (Sisoridae), Eugnathogobius sp., Parawaous sp. (Gobiidae), and Macrognathus maculatus (Mastacembelidae)., Published as part of H. H. Tan & Z. H. Sulaiman, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from the Temburong River basin, Brunei Darussalam, Borneo., pp. 1-19 in Zootaxa 1117 on pages 3-9

Gastromyzon scitulus, new species Figs. 1-2 Material examined: BORNEO: SARAWAK (Sadong River basin). HOLOTYPE: SM uncatalogued, 25.1 mm SL; Serian, Sungai Kuhas, 6.9 km from Tebelu Tebakang turnoff, 5.8 km inside right side road (01��0910.0���N110��2922.7���E); H. H. Tan et al., 5 Sept. 1995. PARATYPES: ZRC 47035, 5 ex., 18.0-23.5 mm SL; CMK 11959, 3 ex., 18.7-23.6 mm SL; same collection data as holotype. The following paratypic lots are also from the type locality, but with different collectors and dates of collection, as indicated. ZRC 47036, 3 ex., 23.3-26.1 mm SL; H. H Tan et al., 14 Jan. 1996. ZRC 47037, 6 ex., 18.4- 26.7 mm SL; H. H. Tan et al., 19 Feb. 1997. SM uncatalogued, 9 ex., 16.7-25.0 mm SL; ZRC 47038, 9 ex., 15.2-29.7 mm SL; Honours 98/99 Fish Group, 23 June 1998. NON-TYPE MATERIAL: ZRC 47046, 4 ex., 23.2-25.0 mm SL; Sarawak: Tebedu, Sungai Ahi, on road towards Mongkos (00��55.44'N110��32.34'E); H. H. Tan et al., 12 June 1999. The following non-type lots are from the type locality, but with different collectors and dates of collection, as indicated. ZRC 41214, 20 ex., 17.0-30.9 mm SL; H. H Tan et al., 19 Feb. 1997. ZRC 43620, 2 ex., 18.1-27.8 mm SL; H. H Tan & W. K. Goh, 6 Feb. 1999. ZRC 47039, 5 ex., 16.6-25.0 mm SL; H. H. Tan et al., 29 Oct. 1997. ZRC 47040, 21 ex., 12.0-23.6 mm SL (site 1, sample 2); ZRC 47041, 4 ex., 12.3-26.8 mm SL (site 1, sample 3); Honours 98/99 Fish Group, 24 June 1998. ZRC 47042, 6 ex., 17.4-28.2 mm SL (site 2, sample 2); ZRC 47043, 14 ex., 15.6-20.5 mm SL (site 2, sample 3); Honours 98/99 Fish Group, 25 June 1998. ZRC 47044, 13 ex., 11.5-21.3 mm SL (site 3, sample 2); Honours 98/99 Fish Group, 26 June 1998. ZRC 47045, 57 ex., 17.2-31.3 mm SL; H. H. Tan et al., 10 June 1999. ZRC 47190, 23 ex., 16.6-30.6 mm SL; native collectors, 22 June 2002. Diagnosis. Gastromyzon scitulus differs from its congeners in having the following unique combination of characters: gill slit angular; subopercular groove present and continuous to pectoral fin origin; body black with numerous evenly spaced small light brown spots, head dorsum black with numerous cream spots, pectoral and pelvic fins with cream spots; caudal fin with iridescent blue streaks in life; sublacrymal groove present; snout strongly sloping from eye to snout, snout rounded when viewed dorsally; absence of a secondary rostrum; absence of a postoral pouch; abdomen without scales; 57-58 scales in lateral line; pelvic fin just reaching anal fin origin, adpressed dorsal fin just reaching level of anal fin origin. Maximum size: 31.3 mm SL (ZRC 47045). Description. General body shape and appearance as in Figs. 1-2. Meristic and morphometric data appear in Table 1. Head rounded in dorsal profile; short (27.6-28.8 % SL) and relatively wide (20.1-21.8 % SL, 69.7-77.3 % HL), head relatively flattened (head depth 13.9-14.9 % SL, 48.5-54.2 % HL), tubercles over entire head; snout relatively long (snout length 53.0-62.5 % HL); sublacrymal groove present, not visible from side; gill slit angular; subopercular groove present and continuous to pectoral fin origin; postoral pouch absent; belly scales absent; posterior part of pectoral fin overlapping anterior fourth of pelvic fin; pelvic fin just touching anal fin origin; serrae on anterior rays of pectoral and pelvic fins; dorsal fin situated about mid body (predorsal length 55.2-58.2 % SL), adpressed dorsal fin just touching level of anal-fin origin; deepest part of body at dorsal-fin origin (body depth at dorsal-fin origin 19.0-20.9 % SL); anus situated just beyond posterior margin of pelvic fin; caudal peduncle short (8.4-10.5 % SL) and relatively narrow (9.9-10.5 % SL). Pigmentation and life coloration.-See Fig. 1. Body dark brown, dorsum and sides with numerous evenly spaced small light brown spots; ventrum cream. Head dorsum dark brown, with numerous cream spots. Eye with golden iris. Dorsal fin base with 3 cream spots. Dorsal fin light brown, with 3 black bars, the subdistal bar most distinct; proximal part of dorsal fin yellowish, with hyaline fin margin and interradial membrane; anterobasal black spot present. Caudal fin base yellowish, fin rays brown, the central portion black and shaped in a figure 8; caudal streaked with iridescent blue on interradial membranes, the top distal half of rays with thick hyaline edge, middle with thin hyaline edge, and bottom half of rays with thin reddish edge. Anal fin brown with 2 black bars and a hyaline edge. Pectoral and pelvic fins dark brown with 2-3 rows of light brown spots and a light brown edge. Pelvic axillary flap brown with 4-5 cream spots. Color in alcohol.-See Fig. 2. Body dark brown or black, the dorsum and sides with numerous faint, evenly spaced small cream spots; ventrum cream. Head dorsum dark brown or black, with numerous cream spots. Dorsal fin base with 3 cream spots. Dorsal fin light brown, with 3 black bars, the subdistal bar most distinct; fin with hyaline interradial membrane and margin; antero-basal black spot present. Caudal fin base grey, fin rays cream, central portion black with figure 8 shape, thick hyaline edge. Anal fin cream, with 2 black bars and hyaline edge. Pectoral and pelvic fins dark brown with 2-3 rows of light brown spots and brown edge. Pelvic axillary flap brown, with faint spots. Remarks.- Gastromyzon scitulus can be further differentiated from G. ctenocephalus by the following characters: dorsal fin without iridescent blue spots (vs. spots present); dorsal fin base with 3 cream spots (vs. 4-5 spots); pelvic axillary flap with 4-5 spots (vs. 7 or more spots); fewer pectoral-fin rays (25-26, mode 25, vs. 27-29, mode 28); fewer pelvic-fin rays (17, vs. 18-19, mode 19); fewer lateral-line scales (57-58, mode 58, vs. 59- 62, mode 60); fewer predorsal scales (24-27, mode 25, vs. 30-33, mode 30); fewer caudalpeduncle scales (5.1.5, vs. 6-7.1.6-7); narrower head width (20.1-21.8, vs. 21.5-27.0 % SL); greater interorbital width (12.3-13.4, vs. 10.7-12.5 % SL). Distribution.- Gastromyzon scitulus is currently only known from the Sadong River basin, in southern Sarawak (Fig. 7). Etymology -The species name is from the Latin scitulus, meaning beautiful, elegant. This is in allusion to the pretty body pattern and coloration in life. Used as an adjective. Field notes.-The type locality, Sungai Kuhas (Fig. 8), is an unshaded hill stream running next to a Bidayuh village (Kampung Lanchang). This village is surrounded by pepper and cocoa plantations, with scrub and secondary vegetation and with some remnant hill forest. The Gastromyzon species are most common above, below, and within the riffle zone, about 1-3 metres wide in shallow running water (pH 7.0) amongst the submerged rocks. Syntopic balitorid species present were Gastromyzon crenastus, G. farragus, Glaniopsis sp., Homaloptera weberi and Nemacheilus saravacensis. Other syntopic species include: Barbonymus collingwoodi, Esomus metallicus [introduced], Hampala macrolepidota, Paracrossocheilus vittata, Puntius banksi, P. kuchingensis, P. orphoides, P. sealei, Rasbora caudimaculata, R. sarawakensis (Cyprinidae), Silurichthys marmoratus (Siluridae), Glyptothorax major (Sisoridae), Clarias leiacanthus (Clariidae), Dermogenys collettei, Hemirhamphodon keukenthali (Hemiramphidae), Betta taeniata (Osphronemidae), Channa gachua, C. lucius (Channidae), and Macrognathus maculatus (Mastacembelidae). Short-term ecological observations were made during a week-long fourth year Honours field course conducted in June 1998. From preliminary surveys conducted earlier, G. farragus was the most common species (65% of total Gastromyzon specimens) and G. crenastus the least common (10% of specimens); which was substantiated by this survey (based on 298 specimens). All three species preferred larger rocks and areas with fast water current. None was obtained from the small rock area with slow water current. However, none was obtained from areas with large rocks and slow water current. Perhaps the larger rocks provide more conducive spots for the fish to reside. Where the water current is strong, smaller sized substratum is usually lacking due to the currents washing these away. There appears to be no difference in gut length between the three species (gut length 248-353 % SL for G. crenastus [n=9], 228-350 % SL for G. farragus [n=12], 234-342 % SL for G. scitulus [n=9]). However, the gut length is consistent with their herbivorous habits, ranging from 248-353 % of standard length (Clayton, 1993). The guts were dissected and the contents of the stomach and foregut examined with a stereoscope. Much of the gut contents was mush and probably consisted of algal and detrital matter. When parts of the gut content were fixed in 75 % alcohol, a greenish colour was leached out, suggesting the presence of chlorophyll, which indicates algal or plant origins., Published as part of H. H. Tan & C. U. M. Leh, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from southern Sarawak., pp. 1-19 in Zootaxa 1126 on pages 3-7

Gastromyzon ridens group Diagnosis.-This species group is defined by a truncate head when viewed dorsally (except for G. ridens, which has a rounded head); sublacrymal groove distinctively visible on lateral part of snout; anterior area of snout with slight depression and densely covered with tubercles; a vertical gill slit; absence of a subopercular groove; absence of a secondary rostrum; absence of a postoral pouch; and absence of scales on abdomen., Published as part of H. H. Tan & C. U. M. Leh, 2006, Three new species of Gastromyzon (Teleostei: Balitoridae) from southern Sarawak., pp. 1-19 in Zootaxa 1126 on page 9

Arius truncatus Valenciennes, in Cuvier and Valenciennes, 1840 Arius truncatus Valenciennes, in Cuvier and Valenciennes, 1840b: 64 (type locality: Java); Weber and de Beaufort, 1913: 308, ®gure 131; Kottelat et al., 1993: 80, pl. 39. Material examined. BATANG HARI DRAINAGE: ZRC 41892 (4), 291.5±309.6 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 297, {"references":["CUVIER, G. and VALENCIENNES, A., 1840 b, Histoire Naturelle des Poissons, V ol. 15, (Strasbourg: Pitois), 540 pp., pls 421 ± 455.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Bagroides melapterus Bleeker, 1851 Bagroides melapterus Bleeker, 1851c: 204 (type locality: Bandjermassing [= Banjarmasin], Borneo); Weber and de Beaufort, 1913: 348, ��gure 147; Jayaram, 1968: 374, ��gure 12; Roberts, 1989: 115; Kottelat et al., 1993: 63, pl. 30. Bagroides melanopterus: Volz, 1904: 469; 1907: 168. Material examined. BATANG HARI DRAINAGE: ZRC 39002 (1), 161.1 mm SL. ZRC 40471 (1), 233.3 mm SL. ZRC 41535 (10), 154.2��201.2 mm SL. ZRC 41901 (5), 206.7��252.7 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat �� shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 271, {"references":["BLEEKER, P., 1851 c, Vierde bijdrage tot de kennis der ichthyologische fauna van Borneo, met beschrijving van eenige nieuwe soorten van zoetwatervisschen, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 2, 193 ± 208.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","JAYARAM, K. C., 1968, Contributions to the study of bagrid ® shes (Siluroidea: Bagridae), 3. A systematic account of the Japanese, Chinese, Malayan and Indonesian genera, Treubia, 27, 287 ± 386.","ROBERTS, T. R., 1989, The freshwater ® shes of Western Borneo (Kalimantan Barat, Indonesia), Memoirs of the California Academy of Sciences, 14, 1 ± 210.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls.","VOLZ, W., 1904, Fische von Sumatra gesammelt von Herrn G. Schneider, Revue Suisse de Zoologie, 12, 451 ± 493.","VOLZ, W., 1907, The ® shes of Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 66, 35 ± 250."]}

Ceratoglanis scleronema (Bleeker, 1862) Hemisilurus scleronema Bleeker, 1862: 93 (type locality: Krawang, Java); Weber and de Beaufort, 1913: 214, ®gure 86; Hardenberg, 1934: 306. Ceratoglanis scleronema: Roberts, 1989: 144; Kottelat et al., 1993: 68, pl. 32. Material examined. BATANG HARI DRAINAGE: CMK 4727 (1), 189.2 mm SL. ZMA 121.819 (1), 216.6 mm SL. ZRC 38981 (2), 158.1, 379.0 mm SL. ZRC 41531 (4), 340.0± 420.0 mm SL. ZRC 41896 (1), 196.0 mm SL. SIAK DRAINAGE: USNM 93287 (1), 356.0 mm SL. Remarks. Crabs (Neorhynchoplax prima Ng and Chuang, 1996; family Hymenosomatidae), isopods, insect remains and remains of a small ®sh were found in the stomach of one specimen dissected. Nothing else is known about the biology of this species., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 281, {"references":["BLEEKER, P., 1862, Atlas Ichthyologique des Indes Orientales Ne AeArlandaises. Tome 2. SilurooEdes, ChacooEdes et He Ate ArobranchooEdes (Amsterdam: Frederic Muller), 112 pp., pls 49 ± 101.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","HARDENBERG, J. D. F., 1934, Additional notes to my paper `` The ® shfauna of the Rokan mouth' ', Treubia, 14, 299 ± 312.","ROBERTS, T. R., 1989, The freshwater ® shes of Western Borneo (Kalimantan Barat, Indonesia), Memoirs of the California Academy of Sciences, 14, 1 ± 210.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Ketengus typus Bleeker, 1847 Ketengus typus Bleeker, 1847: 9 (type locality: Surabaja [= Surabaya], Java); Hardenberg, 1931: 117; 1934: 306; Kottelat et al., 1993: 81, pl. 40., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 297, {"references":["BLEEKER, P., 1847, Nieuwe bijdrage tot de kennis der Siluroiden van Java, Verhandelingen Batav Genootschap, 21, 1 ± 12.","HARDENBERG, J. D. F., 1931, The ® shfauna of the Rokan mouth, Treubia, 13, 81 ± 168.","HARDENBERG, J. D. F., 1934, Additional notes to my paper `` The ® shfauna of the Rokan mouth' ', Treubia, 14, 299 ± 312.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Arius maculatus (Thunberg, 1792) Silurus maculatus Thunberg, 1792: 31, pl. 1 ®gure 2 (type locality: China, Japan). Arius maculatus: Volz, 1907: 172; Weber and de Beaufort, 1913: 284, ®gure 113; Hardenberg, 1931: 116; 1934: 306; Kottelat et al., 1993: 80, pl. 39. Arius pidada Bleeker, 1858a: 25; 1860a: 44; GuÈ nther, 1864: 167; Volz, 1907: 172. Material examined. BATANG HARI DRAINAGE: ZRC 41539 (3), 186.2±207.2 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 296, {"references":["THUNBERG, C. P., 1792, TvaEnne Japanske ® skar beskrifne, Kongliga V etenskaps Akademiens Svenska Handlingen, 13, 29 ± 32.","VOLZ, W., 1907, The ® shes of Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 66, 35 ± 250.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","HARDENBERG, J. D. F., 1931, The ® shfauna of the Rokan mouth, Treubia, 13, 81 ± 168.","HARDENBERG, J. D. F., 1934, Additional notes to my paper `` The ® shfauna of the Rokan mouth' ', Treubia, 14, 299 ± 312.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls.","BLEEKER, P., 1858 a, Zesde bijdrage tot de kennis der vischfauna van Sumatra. Visschen van Padang, Troessan, Priaman, Siboga et Palembang, Acta Societatis Scientiarum Indo- NeeArlandicae, 3, 1 ± 50.","BLEEKER, P., 1860 a, Achtste bijdrage tot de kennis der vischfauna van Sumatra. Visschen van Benkoelen, Priaman, Tandjong, Palembang en Djambi, Acta Societatis Scientiarum Indo-NeeArlandicae, 8, 1 ± 88."]}

Hemipimelodus borneensis (Bleeker, 1851) Pimelodus borneensis Bleeker, 1851d: 430 (type locality: Sambas, Borneo). Hemipimelodus borneensis: Bleeker, 1860a: 47; 1862: 43, pl. 82 ®gure 3; GuÈnther, 1864: 176; Kottelat et al., 1993: 81, pl. 40. Hemipimelodus macrocephalus Hardenberg, 1931: 117; 1934: 306. Material examined. BATANG HARI DRAINAGE: ZRC 41537 (4), 143.9±160.4 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 297, {"references":["BLEEKER, P., 1851 d, Vijfde bijdrage tot de kennis der ichthyologische fauna van Borneo, met beschrijving van eenige nieuwe soorten van zoetwatervisschen, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 2, 415 ± 442.","BLEEKER, P., 1860 a, Achtste bijdrage tot de kennis der vischfauna van Sumatra. Visschen van Benkoelen, Priaman, Tandjong, Palembang en Djambi, Acta Societatis Scientiarum Indo-NeeArlandicae, 8, 1 ± 88.","BLEEKER, P., 1862, Atlas Ichthyologique des Indes Orientales Ne AeArlandaises. Tome 2. SilurooEdes, ChacooEdes et He Ate ArobranchooEdes (Amsterdam: Frederic Muller), 112 pp., pls 49 ± 101.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls.","HARDENBERG, J. D. F., 1931, The ® shfauna of the Rokan mouth, Treubia, 13, 81 ± 168.","HARDENBERG, J. D. F., 1934, Additional notes to my paper `` The ® shfauna of the Rokan mouth' ', Treubia, 14, 299 ± 312."]}

Pseudomystus leiacanthus (Weber and de Beaufort, 1912) L eiocassis leiacanthus Weber and de Beaufort, 1912: 536, pl. 11 ®gure 1, 1a (type localities: Taluk and Ringat [= Rengat], Sumatra); Kottelat et al., 1993: 63, ®gure 151. L eiocassis poecilopterus (non Valenciennes, in Cuvier and Valenciennes, 1840): Klausewitz, 1955: 311. Material examined. BATANG HARI DRAINAGE: SMF 3349 (3), 34.0±52.0 mm. ZRC 38523 (25), 37.9±53.2 mm SL. ZRC 38601 (4), 35.2±42.2 mm SL. ZRC 41664 (1), 32.6 mm SL. ZRC 41819 (15), 23.3±57.3 mm SL. ZRC 41951 (6), 36.6 ±50.7 mm SL. INDRAGIRI DRAINAGE: ZMA 112.672 (1), syntype, 49.9 mm SL. ZRC 39069 (17), 31.0± 46.5 mm SL. Remarks. This species has been found only in peat swamps with very acidic (pH 3.5±4.5) and tannin-stained water., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on pages 280-281, {"references":["WEBER, M. and DE BEAUFORT, L. F., 1912, Die Fische, in A. Mass (ed.) Durch Zentral- Sumatra, V ol. 2 (Leipzig), pp. 522 ± 541.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls.","KLAUSEWITZ, W., 1955, See- und SuEuwasser ® sche von Sumatra und Java, Senckenbergiana Biologica, 36, 309 ± 323."]}

Arius doriae Vinciguerra, 1880 Arius doriae Vinciguerra, 1880: 174 (type locality: Sarawak); Hardenberg, 1931: 117; 1934: 306. Remarks. Although Weber and de Beaufort (1913) considered this species to be distinct, its validity has been doubted by Kottelat et al. (1993). Pending a detailed study of available specimens, this species is tentatively included in the record., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 296, {"references":["VINCIGUERRA, D., 1880, Appunti ittiologici sulle collezioni del Museo Civico de Genova. IV. Prima contribuzione alla Fauna Ittiologica dell'Isola di Borneo. Siluroidei raccolti durante il viaggo dei Signori Mse. G. Doria e Dr. O. Beccari, Annali del Museo Civico di Storia Naturale di Genova, 16, 161 ± 182.","HARDENBERG, J. D. F., 1931, The ® shfauna of the Rokan mouth, Treubia, 13, 81 ± 168.","HARDENBERG, J. D. F., 1934, Additional notes to my paper `` The ® shfauna of the Rokan mouth' ', Treubia, 14, 299 ± 312.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Kryptopterus schilbeides (Bleeker, 1858) Hemisilurus schilbeides Bleeker, 1858c: 7 (type localities: Palembang, Sumatra and Bandjermassin [= Banjarmasin], Borneo). Cryptopterus schilbeides: Weber and de Beaufort, 1913: 216. Kryptopterus schilbeides: Roberts, 1989: 150; Kottelat et al., 1993: 69, pl. 34. Material examined. BATANG HARI DRAINAGE: ZMA 120.538 (7), 71.6±100.9 mm SL. ZMA 120.548 (1), 99.5 mm SL. ZRC 40334 (10), 71.9±89.7 mm SL. ZRC 41894 (1), 83.8 mm SL. ZRC 41895 (2), 128.8, 130.5 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 285, {"references":["BLEEKER, P., 1858 c, Zevende bijdrage tot de kennis der vischfauna van Sumatra, Visschen van Palembang, Acta Societatis Scientiarum Indo-NeeArlandicae, 5, 1 ± 12.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","ROBERTS, T. R., 1989, The freshwater ® shes of Western Borneo (Kalimantan Barat, Indonesia), Memoirs of the California Academy of Sciences, 14, 1 ± 210.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Pangasius djambal Bleeker, 1846 Pangasius djambal Bleeker, 1846b: 290 (type locality: Batavia [= Jakarta], Java). Material examined. BATANG HARI DRAINAGE: ZRC 39129 (1), 196.7 mm. INDRAGIRI DRAINAGE: ZRC 39088 (2), 225.0, 245.0 mm SL. Remarks. Pangasius djambal is so far only known from Java and Borneo (Roberts and Vidthayanon, 1991) and our record of this species represents the ®rst from Sumatra. The fact that such a large ®sh has remained unrecorded from Sumatra until now raises the possibility that its presence is due to introductions from Java or Borneo for aquaculture., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 288, {"references":["BLEEKER, P., 1846 b, Siluroideorum bataviensium species nuperrime detectae, Natuur- en Geneeskundig Archief voor Nederlandsch IndieE, 3, 284 ± 293.","ROBERTS, T. R. and VIDTHAYANON, C., 1991, Systematic revision of the Asian cat ® sh family Pangasiidae, with biological observations and descriptions of three new species, Proceedings of the Academy of Natural Sciences of Philadelphia, 143, 97 ± 144."]}

Akysis heterurus Ng, 1996 Akysis heterurus H. H. Ng, 1996: 4 (type locality: Sungai Alai, Sumatra). Material examined. BATANG HARI DRAINAGE: ZRC 34194 (1), holotype, 18.9 mm SL. ZRC 39248 (7), paratypes, 18.4±26.1 mm SL. CMK 12199 (1), paratype, 21.1 mm SL. MZB 6209 (1), paratype, 25.4 mm SL. ZRC 42309 (2), 20.9, 25.9 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 289

Leiocassis micropogon (Bleeker, 1852) Bagrus micropogon Bleeker, 1852a: 94 (type locality: Blitong [= Billiton], Tjirutjup [= Cirupcup] river). L iocassis micropogon: Volz, 1904: 469; 1907: 167. L eiocassis micropogon: Kottelat et al., 1993: 64, pl. 30. Material examined. BATANG HARI DRAINAGE: ZRC 38704 (1), 89.3 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat �� shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 277, {"references":["BLEEKER, P., 1852 a, Bijdrage tot de kennis der ichthyologische fauna van Blitong (Billiton), met beschrijving van eenige nieuwe soorten van zoetwatervisschen, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 3, 87 ± 100.","VOLZ, W., 1904, Fische von Sumatra gesammelt von Herrn G. Schneider, Revue Suisse de Zoologie, 12, 451 ± 493.","VOLZ, W., 1907, The ® shes of Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 66, 35 ± 250.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Mystus singaringan (Bleeker, 1846) Bagrus singaringan Bleeker, 1846a: 150 (type locality: Batavia [= Jakarta], Java). Macrones nigriceps (non Valenciennes, in Cuvier and Valenciennes, 1840): Volz, 1904: 467; 1907: 165; Weber and de Beaufort, 1913: 337, ®gure 145. Mystus nigriceps: Kottelat et al., 1993: 66, pl. 31. Mystus singaringan: Roberts, 1994: 252, ®gure 6. Material examined. BATANG HARI DRAINAGE: ZRC 38617 (4), 79.2±92.8 mm SL. ZRC 38662 (1), 104.8 mm SL. ZRC 39148 (1), 86.3 mm SL. ZRC 39183 (2), 33.2, 33.5 mm SL. ZRC 41719 (2), 113.1, 138.3 mm SL. ZRC 42262 (2), 109.1, 126.4 mm SL. ZRC 42363 (1), 107.5 mm SL. ZRC 42381 (1), 68.8 mm SL. ZRC 42433 (4), 73.3±131.0 mm SL. Remarks. Most authors since GuÈ nther (1864) have referred to Mystus singaringan as M. nigriceps, but the original description of M. nigriceps is based on Kuhl and van Hasselt material of the species usually identi®ed as M. micracanthus (see Roberts, 1994)., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 278, {"references":["BLEEKER, P., 1846 a, Overzicht der Siluroiden welke te Batavia voorkommen, Natuur- en Geneeskundig Archief voor Nederlandsch IndieE, 3, 135 ± 184.","VOLZ, W., 1904, Fische von Sumatra gesammelt von Herrn G. Schneider, Revue Suisse de Zoologie, 12, 451 ± 493.","VOLZ, W., 1907, The ® shes of Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 66, 35 ± 250.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls.","ROBERTS, T. R., 1994, Systematic revision of Asian bagrid cat ® shes of the genus Mystus sensu stricto, with a new species from Thailand and Cambodia, Ichthyological Exploration of Freshwaters, 5, 241 ± 256."]}

Akysis macronema Bleeker, 1860 (®gure 8) Akysis macronema Bleeker, 1860b: 11 (type locality: Lahat, Sumatra)., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 289, {"references":["BLEEKER, P., 1860 b, Negende bijdrage tot de kennis der vischfauna van Sumatra. Visschen uit de Lematang-Enim en van Benkoelen, Acta Societatis Scientiarum Indo-NeeA rlandicae, 8, 1 ± 12."]}

Chaca bankanensis Bleeker, 1852c Chaca bankanensis Bleeker, 1852c: 455 (type locality: Banka); 1858b: 323; 1860a: 49; 1862: 96, pl. 95 ®gure 1; GuÈnther, 1864: 29; Volz, 1904: 463; 1907: 159; 1907: 159; Weber and de Beaufort, 1912: 537; Roberts, 1982b: 899; Kottelat et al., 1993: 78, pl. 38. Chaca chaca (non Hamilton, 1822): Weber and de Beaufort, 1913: 246, ®gure 99. Material examined. BATANG HARI DRAINAGE: ZRC 38548 (1), 120.5 mm SL. ZRC 38707 (3), 146.7±170.0 mm SL. ZRC 39147 (1), 128.7 mm SL. ZRC 41822 (2), 71.2, 109.5 mm SL. ZRC 42042 (4), 80.2±168.0 mm SL. ZRC 42242 (2), 52.7, 59.8 mm SL. ZRC 42403 (1), 63.6 mm SL. ZRC 42438 (1), 18.2 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 295, {"references":["BLEEKER, P., 1852 c, Bijdrage tot de kennis der ichthyologische fauna van het eiland Banka, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 3, 443 ± 460.","VOLZ, W., 1904, Fische von Sumatra gesammelt von Herrn G. Schneider, Revue Suisse de Zoologie, 12, 451 ± 493.","VOLZ, W., 1907, The ® shes of Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 66, 35 ± 250.","WEBER, M. and DE BEAUFORT, L. F., 1912, Die Fische, in A. Mass (ed.) Durch Zentral- Sumatra, V ol. 2 (Leipzig), pp. 522 ± 541.","ROBERTS, T. R., 1982 b, A revision of the South and Southeast Asian Angler-cat ® shes (Chacidae), Copeia, 1982, 895 ± 901.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls.","HAMILTON, F., 1822, An Account of the Fishes Found in the River Ganges and its Branches (Edinburgh and London), 405 pp., 39 pls.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp."]}

Osteogeneiosus militaris (Linnaeus, 1758) Silurus militaris Linnaeus, 1758: 305 (type locality: Asia). Osteogeneiosus militaris: Weber and de Beaufort, 1913: 329; Hardenberg, 1931: 117; 1934: 306; Kottelat et al., 1993: 81, pl. 40., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 297, {"references":["LINNAEUS, C., 1758, Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, cum Characteribus, Diferentiis, Synonymis, L ocis. Tomus I. Editio decima, reformata (Stockholm: Laurentius Salvius), 824 pp.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","HARDENBERG, J. D. F., 1931, The ® shfauna of the Rokan mouth, Treubia, 13, 81 ± 168.","HARDENBERG, J. D. F., 1934, Additional notes to my paper `` The ® shfauna of the Rokan mouth' ', Treubia, 14, 299 ± 312.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Clarias teijsmanni Bleeker, 1857 Clarias teijsmanni Bleeker, 1857: 344 (type locality:`Tjikoppo, provinciae Buitenzorg, 900 metr. supra mare’, Java). Clarias teijsmanni: Kottelat et al., 1993: 78, pl. 38. Clarias teysmanni: Hubrecht, 1887: 11; Volz, 1904: 463; 1907: 157. Material examined. BATANG HARI DRAINAGE: ZRC 39128 (1), 67.5 mm SL. ZRC 39184 (1), 58.6 mm SL. INDRAGIRI DRAINAGE: ZRC 39105 (4), 37.0±150.0 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on pages 294-295, {"references":["BLEEKER, P., 1857, Descriptiones specierum piscium javanensium novarum vel minus cognitarum diagnosticae, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 13, 323 ± 368.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls.","HUBRECHT, A. A. W., 1887, Tweede afdeeling. Kruipendedieren en visschen. Pisces, in J. F. Snelleman (ed.) Bijdragen tot de Kennis der Fauna van Midden Sumatra. IV. Natuurlijke historie, V ol. I. Fauna (Leiden: E. J. Brill), pp. 9 ± 14.","VOLZ, W., 1904, Fische von Sumatra gesammelt von Herrn G. Schneider, Revue Suisse de Zoologie, 12, 451 ± 493.","VOLZ, W., 1907, The ® shes of Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 66, 35 ± 250."]}

Parakysis grandis Ng and Lim, 1995 Parakysis grandis Ng and Lim, 1995: 260 (type locality: Riau, near Pangkalankasai, Sumatra). Parakysis verrucosa: Kottelat et al., 1993: 76, pl. 37 (in part). Material examined. BATANG HARI DRAINAGE: ZRC 39178 (1), paratype, 29.3 mm SL. ZRC 38632 (3), CMK 11192 (3), 21.8±24.5 mm SL. ZRC 42419 (1), 23.6 mm SL. ZRC 42494 (1), 25.0 mm SL. INDRAGIRI DRAINAGE: ZRC 39111 (1), holotype, 27.8 mm SL. CMK 9032 (5), 16.2±21.8 mm SL. Remarks. See Ng and Lim (1995) for a discussion of the species., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 290, {"references":["NG, H. H. and LIM, K. K. P., 1995, A revision of the Southeast Asian cat ® sh genus Parakysis (Teleostei: Akysidae), with descriptions of two new species, Ichthyological Exploration of Freshwaters, 6, 255 ± 266.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Kryptopterus limpok (Bleeker, 1852) Silurus limpok Bleeker, 1852d: 583 (type locality: Palembang, Sumatra). Cryptopterus limpok: Volz, 1904: 465; 1907: 160; Weber and de Beaufort, 1913: 219. Kryptopterus limpok: Roberts, 1989: 147; Kottelat et al., 1993: 69, pl. 33. Material examined. BATANG HARI DRAINAGE: CMK 11237 (1), 147.0 mm SL. ZMA 120.535 (3), 105.4±168.4 mm SL. ZRC 38616 (1), 177.3 mm SL. SIAK DRAINAGE: USNM 93289 (2), 142.8, 162.7 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 284, {"references":["BLEEKER, P., 1852 d, Diagnostische beschrijvingen van nieuwe of weinig bekende vischsoorten van Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 3, 569 ± 608.","VOLZ, W., 1904, Fische von Sumatra gesammelt von Herrn G. Schneider, Revue Suisse de Zoologie, 12, 451 ± 493.","VOLZ, W., 1907, The ® shes of Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 66, 35 ± 250.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","ROBERTS, T. R., 1989, The freshwater ® shes of Western Borneo (Kalimantan Barat, Indonesia), Memoirs of the California Academy of Sciences, 14, 1 ± 210.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Acrochordonichthys cf. melanogaster (Bleeker, 1854) Pimelodus melanogaster Bleeker, 1854: 89 (type locality: eastern Sumatra, Palembang province, at the conūence of the Lamatang and Enim rivers). Material examined. WEST SUMATRA DRAINAGES: ZMA 101.956 (2), 74.6, 81.8 mm SL. Remarks. The taxonomy of Acrochordonichthys species is confused at the moment (Roberts, 1989) and pending a more detailed study, the identity of these specimens is tentative., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 288, {"references":["BLEEKER, P., 1854, Overzigt der ichthyologische fauna van Sumatra met beschrijving van eenige nieuwe soorten, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 7, 49 ± 108.","ROBERTS, T. R., 1989, The freshwater ® shes of Western Borneo (Kalimantan Barat, Indonesia), Memoirs of the California Academy of Sciences, 14, 1 ± 210."]}

Pseudomystus stenomus (Valenciennes, in Cuvier and Valenciennes, 1840) Bagrus stenomus Valenciennes, in Cuvier and Valenciennes, 1840a: 415 (type locality: Java). L eiocassis stenomus Weber and de Beaufort, 1913: 355; Kottelat et al., 1993: 65, pl. 31. Material examined. BATANG HARI DRAINAGE: ZMA 121.531 (3), 45.9±58.6 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 281, {"references":["CUVIER, G. and VALENCIENNES, A., 1840 a, Histoire Naturelle des Poissons, V ol. 14, (Paris: Pitois-Levrault), 464 pp., pls 389 ± 420.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Breitensteinia cessator Ng and Siebert, 1998 Breitensteinia cessator Ng and Siebert, 1998: 647, ®gure 1 (type locality: Kapuas river). Breitensteinia insignis: Weber and de Beaufort, 1913: 374, ®gure 151 (in part); Roberts, 1989: 140 (in part). Material examined. BATANG HARI DRAINAGE: ZMA 104.653 (1), paratype, 75.3 mm SL. Remarks. See Ng and Siebert (1998) for a discussion of the species., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 290, {"references":["NG, H. H. and SIEBERT, D. J., 1998, A revision of the akysid cat ® sh genus Breitensteinia Steindachner with descriptions of two new species, Journal of Fish Biology, 53, 645 ± 657.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","ROBERTS, T. R., 1989, The freshwater ® shes of Western Borneo (Kalimantan Barat, Indonesia), Memoirs of the California Academy of Sciences, 14, 1 ± 210."]}

Arius goniaspis Bleeker, 1858 Arius goniaspis Bleeker, 1858a: 44 (type locality: Priaman, Sumatra); GuÈnther, 1864: 166; Volz, 1907: 172; Weber and de Beaufort, 1913: 283. Ariodes goniaspis: Bleeker, 1858b: 91; 1862: 42, pl. 60 ®gure 1. Material examined. BATANG HARI DRAINAGE: ZRC 41538 (1), 192.0 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 296, {"references":["BLEEKER, P., 1858 a, Zesde bijdrage tot de kennis der vischfauna van Sumatra. Visschen van Padang, Troessan, Priaman, Siboga et Palembang, Acta Societatis Scientiarum Indo- NeeArlandicae, 3, 1 ± 50.","VOLZ, W., 1907, The ® shes of Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 66, 35 ± 250.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","BLEEKER, P., 1858 b, Ichthyologiae archipelagi indici prodromus, V ol. 1 Siluri (Batavia: Lange and Co.), 370 pp.","BLEEKER, P., 1862, Atlas Ichthyologique des Indes Orientales Ne AeArlandaises. Tome 2. SilurooEdes, ChacooEdes et He Ate ArobranchooEdes (Amsterdam: Frederic Muller), 112 pp., pls 49 ± 101."]}

Ompok cf. bimaculatus (Bloch, 1794) Silurus bimaculatus Bloch, 1794: 24, pl. 364 (type locality: Tranquebar, India). Callichrous bimaculatus: Volz, 1904: 465; 1907: 162; Weber and de Beaufort, 1913: 209. W allago miostoma: Weber and de Beaufort, 1913: 202 (in part). Ompok bimaculatus: Kottelat et al., 1993: 70, pl. 34. Remarks. Kottelat and Lim (1995b) considered the Southeast Asian material of O. bimaculatus to belong to a species distinct from O. bimaculatus as originally described and illustrated by Bloch (1794). Until a critical comparison can be made between the Indian and Southeast Asian material, we tentatively use the name O. cf. bimaculatus, Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 285, {"references":["BLOCH, M. E., 1794, Naturgeschichte der Auslandischen Fische. Achter Teil (Berlin: Morino), 174 pp., pls 361 ± 396.","VOLZ, W., 1904, Fische von Sumatra gesammelt von Herrn G. Schneider, Revue Suisse de Zoologie, 12, 451 ± 493.","VOLZ, W., 1907, The ® shes of Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 66, 35 ± 250.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls.","KOTTELAT, M. and LIM, K. K. P., 1995 b, Freshwater ® shes of Sarawak and Brunei Darussalam: a preliminary annotated checklist, Sarawak Museum Journal, 48, 227 ± 256."]}

Clarias nieuho ®i Valenciennes, in Cuvier and Valenciennes, 1840 Clarias nieuho ®i Valenciennes, in Cuvier and Valenciennes, 1840b: 386 (type locality: Indies); Bleeker, 1858b: 351. Clarias nieuho®: Bleeker, 1862: 105, pl. 99 ®gure 2. Clarias nieuho®: Volz, 1904: 463; 1907: 158. Clarias nieuho ®i: Weber and de Beaufort, 1912: 533; 1913: 189; Kottelat et al., 1993: 78, pl. 38. Material examined. BATANG HARI DRAINAGE: ZRC 38978 (5), 200.0±238.0 mm SL. INDRAGIRI DRAINAGE: ZRC 39093 (5), 204.5±358 mm SL. Remarks. We have examined the type of C. pentapterus Bleeker, 1851, and found them to be conspeci®c with the holotype of C. nieuho ®i., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 292, {"references":["CUVIER, G. and VALENCIENNES, A., 1840 b, Histoire Naturelle des Poissons, V ol. 15, (Strasbourg: Pitois), 540 pp., pls 421 ± 455.","BLEEKER, P., 1858 b, Ichthyologiae archipelagi indici prodromus, V ol. 1 Siluri (Batavia: Lange and Co.), 370 pp.","BLEEKER, P., 1862, Atlas Ichthyologique des Indes Orientales Ne AeArlandaises. Tome 2. SilurooEdes, ChacooEdes et He Ate ArobranchooEdes (Amsterdam: Frederic Muller), 112 pp., pls 49 ± 101.","VOLZ, W., 1904, Fische von Sumatra gesammelt von Herrn G. Schneider, Revue Suisse de Zoologie, 12, 451 ± 493.","VOLZ, W., 1907, The ® shes of Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 66, 35 ± 250.","WEBER, M. and DE BEAUFORT, L. F., 1912, Die Fische, in A. Mass (ed.) Durch Zentral- Sumatra, V ol. 2 (Leipzig), pp. 522 ± 541.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Arius sagor Hamilton, 1822 Arius sagor Hamilton, 1822: 169 (type locality: Ganges drainage, India); Weber and de Beaufort, 1913: 289, ®gure 115; Hardenberg, 1931: 116; 1934: 306., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 296, {"references":["HAMILTON, F., 1822, An Account of the Fishes Found in the River Ganges and its Branches (Edinburgh and London), 405 pp., 39 pls.","WEBER, M and DE BEAUFORT, L. F., 1913, T he ® shes of the Indo-Australian Archipelago, V ol. 2. Malacopterygii, Myctophoidea, Ostariophysi: I. Siluroidea (Leiden: E. J. Brill), 404 pp.","HARDENBERG, J. D. F., 1931, The ® shfauna of the Rokan mouth, Treubia, 13, 81 ± 168.","HARDENBERG, J. D. F., 1934, Additional notes to my paper `` The ® shfauna of the Rokan mouth' ', Treubia, 14, 299 ± 312."]}

Kryptopterus hexapterus (Bleeker, 1851) Silurus hexapterus Bleeker, 1851c: 203 (type locality: Bandjermassing [= Banjarmasin], Borneo). Cryptopterus hexapterus: Hardenberg, 1931: 115; 1934: 306., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 284, {"references":["BLEEKER, P., 1851 c, Vierde bijdrage tot de kennis der ichthyologische fauna van Borneo, met beschrijving van eenige nieuwe soorten van zoetwatervisschen, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 2, 193 ± 208.","HARDENBERG, J. D. F., 1931, The ® shfauna of the Rokan mouth, Treubia, 13, 81 ± 168.","HARDENBERG, J. D. F., 1934, Additional notes to my paper `` The ® shfauna of the Rokan mouth' ', Treubia, 14, 299 ± 312."]}

Batrachocephalu s mino (Hamilton, 1822) Ageneiosus mino Hamilton, 1822: 159 (type locality: Ganges drainage, India). Batrachocephalus mino: Kottelat et al., 1993: 80, pl. 39. Material examined. BATANG HARI DRAINAGE: ZRC 41536 (1), 174.5 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 297, {"references":["HAMILTON, F., 1822, An Account of the Fishes Found in the River Ganges and its Branches (Edinburgh and London), 405 pp., 39 pls.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Mystus bimaculatus Volz, 1904 Macrones bimaculatus Volz, 1904: 466 (type locality: Sungai Si Russu and Kwantan river, Djapura, Indragiri, Sumatra); 1907: 165. Mystus bimaculatus: Kottelat et al., 1993: 65, pls. 2, 31. Material examined. BATANG HARI DRAINAGE: ZRC 38524 (7), 49.3±58.1 mm SL. ZRC 38602 (3), 43.8±50.2 mm SL. ZRC 39125 (1), 40.8 mm SL. ZRC 39167 (1), 33.2 mm SL. ZRC 41821 (2), 25.1, 26.5 mm SL. ZRC 42440 (5), 22.5±33.2 mm SL. ZRC 42491 (42), 24.4±66.9 mm SL. INDRAGIRI DRAINAGE: ZRC 39072 (2), 48.1, 50.3 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 277, {"references":["VOLZ, W., 1904, Fische von Sumatra gesammelt von Herrn G. Schneider, Revue Suisse de Zoologie, 12, 451 ± 493.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Laides hexanema (Bleeker, 1852d) Pangasius hexanema Bleeker, 1852d: 588 (type localities: Palembang, Sumatra and Batavia [= Jakarta], Java). L ais hexanema: Weber and de Beaufort, 1912: 535; 1913: 250, ®gure 101. L aides hexanema: Roberts, 1989: 131; Kottelat et al., 1993: 71, pl. 35. Material examined. BATANG HARI DRAINAGE: CMK 4697 (1), 90.8 mm SL. ZMA 120.521 (2), 86.0±89.0 mm SL. ZRC 41554 (2), 88.5, 101.4 mm SL. INDRAGIRI DRAINAGE: ZMA 120.522 (1), 95.8 mm SL. ZMA 120.523 (1), 113. 0 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on pages 286-287, {"references":["BLEEKER, P., 1852 d, Diagnostische beschrijvingen van nieuwe of weinig bekende vischsoorten van Sumatra, Natuurkundig T ijdschrift voor Nederlandsch IndieE, 3, 569 ± 608.","WEBER, M. and DE BEAUFORT, L. F., 1912, Die Fische, in A. Mass (ed.) Durch Zentral- Sumatra, V ol. 2 (Leipzig), pp. 522 ± 541.","ROBERTS, T. R., 1989, The freshwater ® shes of Western Borneo (Kalimantan Barat, Indonesia), Memoirs of the California Academy of Sciences, 14, 1 ± 210.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}

Ompok eugeneiatus (Vaillant, 1893) Callichrous eugeneiatus Vaillant, 1893: 61 (type locality: Kapuas, Borneo). Silurodes eugeneiatus: Weber and de Beaufort, 1912: 534 ±535, pl. 12 ®gure 1; 1913: 207, ®gure 80. Ompok eugeneiatus: Kottelat et al., 1993: 70, pl. 34. Material examined. BATANG HARI DRAINAGE: ZMA 120.537 (1), 100.2 mm SL. ZRC 41678 (5), 37.6±86.4 mm SL. INDRAGIRI DRAINAGE: ZMA 113.097 (1), 104.8 mm SL. ZRC 39036 (2), 81.7, 83.3 mm SL., Published as part of Ng, H. H. Tan H. H., 2000, The cat ® shes (Teleostei: Siluriformes) of central Sumatra, pp. 267-303 in Journal of Natural History 34 on page 285, {"references":["VAILLANT, L., 1893, Sur une collection de poissons recueillie par M. Chaper, a Borne Ao, Bulletin. Societe Zoologique de France, 18, 55 ± 62.","WEBER, M. and DE BEAUFORT, L. F., 1912, Die Fische, in A. Mass (ed.) Durch Zentral- Sumatra, V ol. 2 (Leipzig), pp. 522 ± 541.","KOTTELAT, M., WHITTEN, A. J., KARTIKASARI, S. N. and WIRJOATMODJO, S., 1993, Freshwater Fishes of W estern Indonesia and Sulawesi (Hong Kong: Periplus Editions), 221 pp., 84 pls."]}