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Pseudobagarius eustictus, new species, is described from the Nam Heung drainage (a tributary of the Mekong River) in northern Laos. It is distinguished from congeners in having a unique combination of the following characters: a weakly-produced snout in which the upper jaw extends only slightly beyond the margin of the lower jaw when viewed ventrally, 3 tubercles on the posterior margin of the pectoral spine, eye diameter 8% HL, head width 24.1% SL, dark yellow dorsal and lateral surfaces of the head, pectoral spine lacking elongate extensions, pectoral fin reaching the pelvic-fin base when adpressed against the body, dorsolateral surfaces of body without longitudinal series of prominent tubercles, body depth at anus 13.7% SL, length of adipose-fin base 17.7% SL, caudal-peduncle depth 7.0% SL, and 33 vertebrae.

A new species of Macrognathus of the M. aculeatus species group is described from the Kahayan River drainage in southern Borneo, Kalimantan Tengah, Indonesia. Macrognathus kris, new species, is distinguished from all Asian congeners in having the following unique combination of characters: rim of anterior nostril with two fimbriae and two fimbrules; 43–45 rostral tooth plates; 24–25 dorsal spines; 46–55 dorsal-fin rays; 51–59 anal-fin rays; 20–23 principal caudal-fin rays; 76–78 total vertebrae; body depth at anus 11.8–15.9% SL; color pattern consisting of light brown stripe on dorsum and 11–14 irregular pentagonal dark brown blotches on sides of body.

Pterocryptis subrisa, a new species of silurid catfish from the Kaladan River drainage in northeastern India, is described in this study. It can be distinguished from congeners by the unique combination of the following characters: supralabial fold extending posteriorly beyond vertical through posterior orbital margin; nearly circular eye; head length 17.6–19.6% SL; head depth 10.6–11.9% SL; dorsal-fin height 2.6–4.7% SL; 2 dorsal-fin rays; pectoral-fin length 11.8–14.0% SL; body depth at anus 14.4–16.7% SL; caudal peduncle depth 6.8–8.5% SL; 66–75 anal-fin rays; confluent anal and caudal fins separated by deep notch; 17 principal caudal-fin rays; and 57 vertebrae. The generic status of Pterocryptis taytayensis is discussed, with this species being reassigned to Ompok.

We resolve the identity of the glass catfish, a species of Asian freshwater fish commonly encountered as an ornamental fish and an experimental subject that has long been misidentified as either Kryptopterus bicirrhis or K. minor. Our study indicates that the glass catfish is an unnamed species distinct from either, which we describe here as Kryptopterus vitreolus. Kryptopterus vitreolus is known from river drainages in peninsular and southeastern Thailand, and is distinguished from congeners in having a combination of: transparent body in life, maxillary barbels reaching beyond the base of the first anal-fin, dorsal profile with a pronounced nuchal concavity, snout length 29–35% head length (HL), eye diameter 28–34% HL, slender body (depth at anus 16–20% standard length (SL)) and caudal peduncle (depth 4–7% SL), 14–18 rakers on the first gill arch, and 48–55 anal-fin rays.

Tachysurus spilotus, a new species of catfish from central Vietnam, is described. It can be distinguished from congeners except T. argentivittatus, T. longispinalis, and T. virgatus in having a color pattern consisting of black longitudinal stripes on a pale body (vs. with a uniform-colored body with pale patches or transverse bands on a dark body, or with dark rectangular patches on a pale body). It differs from both T. argentivittatus and T. virgatus in snout shape and having gently convex (vs. straight) posterior edges of the caudal-fin lobes; and from T. longispinalis in having a shorter dorsalfin spine (ca. 27% SL vs. 15.1–19.0) and maxillary barbels (shorter, vs. longer than head). Tachysurus mica is shown here to be conspecific with—and a junior synonym of—T. argentivittatus.

Ompok brevirictus, a new species of silurid catfish is described from the short coastal rivers draining the western face of the Leuser Mountain Range and debouching into the Indian Ocean in Nangroe Aceh Darussalam province, northern Sumatra. Ompok brevirictus can be distinguished from Ompok siluroides and O. miostomus, the Southeast Asian congeners that it most resembles, in having an evenly convex predorsal profile (vs. with a concavity posterior to orbit) and a more prominent lower jaw that is more broadly curving. Ompok brevirictus additionally differs from O. siluroides in having the mouth rictus separated from the anterior orbital margin by a distance of one-third (vs. less than one-third) eye diameter (4.2–5.2% HL vs. 3.2–3.7) and lacking (vs. with) a distinct dark wedge-shaped spot on the base of the caudal fin. The identity of the Southeast Asian material usually identified as O. bimaculatus is also clarified. Ompok bimaculatus is restricted to the Indian subcontinent and Myanmar in this study; the Southeast Asian material previously identified as conspecific is hereby referred to either O. siluroides or O. miostomus.

Akysis pulvinatus, new species, is described from southern Thailand. It can be distinguished from congeners in having a combination of: length of adipose-fin base 23.0–25.2% SL, body depth at anus 13.2–16.0% SL, caudal peduncle depth 9.4–10.3% SL, head length 27.6–29.8% SL, head width 21.9–25.1% SL, length of nasal barbel 13.9–57.5% HL, length of maxillary barbel 78.5–105.0% HL, smooth posterior edge of pectoral spine, gently forked caudal fin with lower lobe longer than upper, yellow snout, and rounded pale colored patches on body. A possible case of Müllerian mimicry with the syntopic Pseudobagarius leucorhynchus is mentioned and briefly discussed.

Botia udomritthiruji sp. nov. is described from the Tenasserim River drainage in southern Myanmar. It can be distinguished from congeners by its color pattern, consisting of five dark vertical bars on the body, with the central portion of these bars paler than its edges; with increasing age, the edges of these bars become more irregular and darker, and irregular dark spots on the pale interspaces begin to form, sometimes fusing with the edges of the vertical bars. In morphology, it differs from congeners by a combination of: body depth at anus 23.4–27.7% SL, caudal peduncle depth 15.9– 18.7% SL, and 12 dorsal-fin rays. Evidence for considering B. macrolineata a junior synonym of B. dario and for considering B. rostrata a species distinct from B. almorhae is also presented here.

The species of Glyptothorax of Sundaic Southeast Asia (Malay Peninsula, Sumatra, Borneo and Java) are revised in this study. A total of 17 species are recognized, of which six ( G. amnestus , G. decussatus , G. famelicus , G. keluk , G. pictus and G. stibaros ) are described as new here. A lectotype is designated for G. platypogon . The Sundaic Glyptothorax species are diagnosed by combinations of color pattern, morphometry (with particular regard to the eye, head, body depth, and caudal peduncle), dorsal-spine and thoracic adhesive apparatus morphology.

This study describes a new diminutive sisorid catfish from the upper reaches of the Karnaphuli River drainage in northeastern India. The new species can be distinguished from congeners in having a combination of: length of dorsal-fin spine 18.0–21.6% SL; 4–10 serrations on the anterior edge of the dorsal spine; length of pectoral-fin spine 20.7–26.1% SL; length of adipose-fin base 21.5–26.3% SL; body depth at anus 12.3–15.9% SL; caudal peduncle depth 7.5–9.8% SL; caudal peduncle length 17.0–20.5% SL; pale, y-shaped marking on dorsal surface of head; sides of body with pale yellowish patches and irregular bands.

We describe Olyra praestigiosa , a new anguilliform bagrid catfish, from the Brahmaputra River drainage in Bangladesh and northeastern India. The new species differs from congeners in having the following unique combination of characters: interorbital distance 30–37% HL; body depth at anus 6–9% SL; length of adipose-fin base 99–16% SL; adipose fin separate from upper principal caudal-fin rays; post-adipose distance 15–18% SL; 17–22 anal-fin rays; caudal peduncle length 14–19% SL; and caudal peduncle depth 6–8% SL.

The identity of Pseudecheneis sulcata is clarified in this study, and the species is redescribed. Pseudecheneis sulcata (from the Brahmaputra River drainage) can be distinguished from congeners in having a unique combination of the lack of a prominent bony spur on the anterodorsal surface of the first dorsal-fin pterygiophore, presence of a first dorsal-fin element, bifid neural spines on the complex vertebra, the neural spines of the last 2–3 preanal and first 6–7 postanal vertebrae gradually increasing in height, separate pelvic fins, a less convex snout when viewed laterally, presence of pale spots on the body, 36–39 vertebrae, 12–14 transverse laminae on the thoracic adhesive apparatus, pelvic-fin length 21.2–28.7% SL, pectoral-fin length 121.6–156.3 % HL, length of adipose-fin base 17.8–22.7% SL, length of caudal peduncle 25.0–28.3% SL, depth of caudal peduncle 4.0–5.2% SL, and eye diameter 8.8–10.6% HL. Pseudecheneis eddsi, new species, is described from tributaries of the Ganges River in Nepal. Pseudecheneis eddsi can be distinguished from congeners by a unique combination of the presence of a prominent bony spur on the anterodorsal surface of the first dorsal-fin pterygiophore, presence of a first dorsal-fin element, bifid neural spines on the complex vertebra, the neural spines of the last 2–3 preanal and first 6–7 postanal vertebrae gradually increasing in height, separate pelvic fins, gently rounded snout when viewed dorsally, presence of pale spots on the body, 36–39 vertebrae, pelvic-fin length 18.0–20.9% SL, pectoral-fin length 114.9–156.0% HL, length of adipose-fin base 19.5–24.3% SL, length of caudal peduncle 25.2–27.8% SL, depth of caudal peduncle 3.5–5.3% SL, and eye diameter 9.6–12.8% HL. Pseudecheneis stenura, new species, is also described from the Irrawaddy River drainage in southwestern China. Pseudecheneis stenura can be distinguished from congeners by a unique combination of the presence of a prominent bony spur on the anterodorsal surface of the first dorsal-fin pterygiophore, presence of a first dorsal-fin element, bifid neural spines on the complex vertebra, the neural spines of the last 2–3 preanal and first 6–7 postanal vertebrae gradually increasing in height, separate pelvic fins, presence of pale spots on the body, 38–40 vertebrae, pelvic-fin length 20.4–24.3% SL, pectoral-fin length 160.4–196.9% HL, length of adipose-fin base 18.8–23.7% SL, length of caudal peduncle 30.3–34.5% SL, depth of caudal peduncle 2.9–3.6% SL, and eye diameter 9.2–12.8% HL. A key to the species of Pseudecheneis is provided.

Clarias serniosus , a new Southeast Asian walking-catfish species, is described from the Bolavens Plateau in southern Laos. The new species is a member of the C. batrachus species complex, and can be distinguished from congeners in the complex in having a combination of: occipital process length 15–17 % HL, head length 28.2–28.6% SL, head width 18.5–19.2% SL, head depth 13.0–13.7% SL, distance between the occipital process and the base of the first dorsal-fin ray 8.5% SL, smooth anterior edge of pectoral spine, 67 dorsal-fin rays, body depth at anus 16.2–16.5% SL, and 57 total vertebrae.

We review members of the sisorid catfish genus Exostoma known from Thailand. Three species are recognized, of which two from the headwaters of the Chao Phraya River drainage in northwestern Thailand, are described here as new: E. effrenum and E. peregrinator. In addition to the two new species, E. berdmorei (which is here redescribed) is also known from the Salween River drainage in western Thailand. The three species can be distinguished from each other and other congeners by the morphologies of the adipose and caudal fins, as well as morphometric data for the eye diameter, head width, dorsal-to-adipose distance, body depth at anus, caudal-peduncle length, caudal-peduncle depth, and numbers of branched pectoral-fin rays and preanal vertebrae.

Olyra saginata, new species, is described from the Kaladan [=Kolodyne] River system in Mizoram, northeast India. It differs from congeners in having the following unique combination of characters: interorbital distance 27.9–35.9% HL; 54–66 lateral-line pores; body depth at anus 10.5–12.0% SL; length of adipose-fin base 17.3–22.4% SL; adipose fin separate from upper principal caudal-fin rays; post-adipose distance 11.8–14.3% SL; caudal peduncle length 14.8–17.7% SL; and caudal peduncle depth 7.8–8.9% SL. The taxonomy of congeners is also briefly discussed.

Ompok karunkodu, a new species of silurid catfish is described from the Amaravathi River, a right-hand tributary of the Kaveri [=Cauvery] River in Tamil Nadu, southern India. Ompok karunkodu can be distinguished from all congeners in the Indian subcontinent in having a markedly convex predorsal profile (vs. with a slight or distinct concavity in the supraethmoidal or supraoccipital region), and a unique combination of the following characters: prognathous lower jaw causing anterior profile of head to appear rounded when viewed laterally, maxillary barbel reaching to base of pectoral-fin spine, eye diameter 13.7% HL, head width 13.0% SL, body depth at anus 14.2% SL, 65 anal-fin rays, caudal peduncle depth 5.0% SL, caudal-fin length 12.6% SL, caudal fin with rounded lobes, 54 vertebrae, and dark midlateral stripe running along sides of body.

Psilorhynchus sucatio (Hamilton) is redescribed based on the examination of 462 specimens, 13-67 mm standard length (SL). Psilorhynchus nudithoracicus Tilak & Husain is redescribed based on the examination of 97 specimens, 10-68 mm SL. Psilorhynchus gracilis Rainboth is placed in the synonymy of P nudithoracicus. Psilorhynchus hamiltoni, a new species and a member of the P. balitora species group, is described from the Tista River in West Bengal, India. It is distinguished from all other members of the P. balitora species group by having a well-developed lateral stripe, 6-7 poorly developed saddles that do not make contact with the lateral blotches, 7-11 lateral blotches, 34-35 lateral line scales, 9+8-9 principal caudal-fin rays, 36 total vertebrae, and the ventral surface between paired fins with a broad rectangular scaleless patch. A key to the species groups of Psilorhynchus is also provided, as are revised diagnoses for the P. balitora and P. nudithoracicus species groups.

Glyptothorax radiolus , new species, is described from the Brahmaputra River drainage in West Bengal, northeast India. It differs from most congeners in the Indian subcontinent in possessing plicae on the ventral surfaces of the pectoral spine and first pelvic-fin ray. The following combination of characters serve to distinguish it from congeners in the Indian sub-continent with plicate ventral surfaces of the pectoral spine and first pelvic-fin ray: eye diameter 6.6–7.4% HL interorbital distance 28.3–28.7% HL, head length 23.7–24.3% SL, wedge-shaped central depression in throracic adhesive apparatus devoid of skin ridges, unculiferous ridges of thoracic adhesive apparatus not extending anteriorly onto gular region, pec-toral fin length 21.4–22.8% SL, dorsal-fin spine length 11.6–13.9% SL, dorsal-to-adipose distance 26.6–26.8% SL, body depth at anus 11.2–11.4% SL, pelvic fin length 16.5–18.3% SL, adipose-fin base length 13.1–14.3% SL, anal-fin base length 13.4–14.0% SL, caudal peduncle length 20.9% SL, caudal peduncle depth 7.7% SL (1.4–1.5 times in body depth at anus), absence of distinct pale midlateral stripe on body, and 36 total vertebrae. Glyptothorax striatus , the type species of the genus, is also rediagnosed and redescribed in this study.

Glyptothorax igniculus, new species, is described from the Chindwin River system (part of the Irrawaddy River drainage) in northwestern Myanmar. It differs from other species of Glyptothorax in the Irrawaddy drainage except G. burmanicus in having a thoracic adhesive apparatus with a lanceolate central depression that is nearly enclosed posteriorly by skin ridges, vs. having an adhestive apparatus that is open caudally. In G. burmanicus the adhesive apparatus is oval in outline and completely closed. Glyptothorax chindwinicus Vishwanath & Linthoingambi, 2007 is shown to be a junior synonym of G. burmanicus Prashad & Mukerji, 1929. Glyptothorax rugimentum is reported for the first time from the Chindwin drainage.

This study describes Pseudolaguvia nubila, a new miniature sisorid catfish from the Kaladan River drainage in northeastern India. Pseudolaguvia nubila can be distinguished from congeners in having a combination of a mottled brown body with yellowish bands, a weakly projecting snout in which the premaxillary teeth are barely exposed when the mouth is closed, head width 19.7-21.7% standard length (SL), eye diameter 10.8-14.0% head length (HL), interorbital distance 25.6-31.8% HL, absence of a pale Y-shaped marking on the dorsal surface of the head and supraoccipital process, a smooth anterior edge of the dorsal spine, dorsal-fin spine length 16.4-19.3% SL, length of dorsal-fin base 15.1-17.3% SL, 7-8 serrations on the anterior edge of the pectoral spine, pectoral-fin spine length 18.1-22.0% SL, dorsal to adipose distance 13.1-16.8% SL, length of adipose-fin base 14.2-15.9% SL, pelvic-fin length 15.8-18.5% SL, body depth at anus 13.9-17.1% SL, caudal-peduncle length 15.7-20.2% SL, caudal-peduncle depth 9.1-11.1% SL, and caudal-fin length 20.3-25.3% SL.

This study describes Pseudolaguvia viriosa, a new miniature sisorid catfish from the Brahmaputra River drainage in Ar-unachal Pradesh, northeastern India. Pseudolaguvia viriosa can be distinguished from congeners in having a combinationof: eye diameter 10–15% HL, interorbital distance 35–38% HL, head width 21.5–23.5% SL, thoracic adhesive apparatusreaching beyond base of last pectoral-fin ray, pectoral spine length 26.9–32.9% SL, dorsal spine length 23.4–29.0% SL,dorsal spine with anterior edge smooth or with rugose surface only on distal third of spine, body depth at anus 16.9–19.0%SL, length of adipose-fin base 12.5–15.4% SL, caudal peduncle length 14.8–17.7% SL, caudal peduncle depth 7.4–9.8% SL, caudal-fin length 26.5–32.4% SL, 28–29 vertebrae, and one or more distinct pale bands encircling body.

Tonlesapia amnica, a new species of dragonet lacking a first dorsal fin, is described from the Mekong River delta in southern Vietnam. It can be distinguished from its sole congener, T. tsukawakii, in having the infraorbital canal extending beyond (vs. not reaching) ventral margin of orbit, a more slender body (7.2–13.5% SL vs. 14.3–15.0) and caudal peduncle (4.4–5.2% SL vs. 5.1–6.3), a smaller eye (6.5–8.3% SL vs. 8.7–9.2) and more dorsal-fin rays (9–10 vs. 8).

Pseudeutropius indigens, a new species of schilbeid catfish from peninsular Thailand, is described here. It can be distinguished from congeners in having the following combination of characters: head length 23.1–24.3% SL, head width 10.5– 11.0% SL, length of anal-fin base 45.6–50.4% SL, 37–41 anal-fin rays, isognathous jaws in which the premaxillary teeth are not visible when the mouth is closed, and long nasal, maxillary and mandibular barbels that reach to at least the analfin origin.

Clarias gracilentus, a new Southeast Asian walking catfish species, is described from Phu Quoc Island (Vietnam) off the coast of southeastern Cambodia and from mainland southeastern Cambodia. The new species is a member of the C. nieuhofii species complex, and can be distinguished from congeners in the complex in having a combination of: head width 11.9–12.9% SL, distance between the occipital process and the base of the first dorsal-fin ray 5.3–8.4% SL, pectoral-fin length 8.5–10.1% SL, body depth at anus 8.2–11.7% SL, pelvic-fin length 4.3–5.5% SL, length of anal-fin base 60.0–63.9% SL, eye diameter 5.4–7.2% HL, interorbital distance 42.7–48.0% HL, occipital-process length 7.8–14.7% HL, 96–101 dorsal-fin rays, 84–89 anal-fin rays and 80–84 total vertebrae.

Nanobagrus lemniscatus, a new species of miniature bagrid catfish from the Malay Peninsula is described here. It can be distinguished from congeners in having the following combination of characters: large cream patches on a brown body frequently coalescing to form broad transverse band, length of adipose-fin base 24.0–27.1% SL, body depth at anus 13.1–14.0% SL, 35–36 vertebrae, pectoral spine with length 16.1–18.7% SL and 7–9 serrations on its posterior margin, and a convex neurocranium. Nanobagrus stellatus is also recorded from the Malay Peninsula for the first time in this study.

This study describes Pseudolaguvia spicula, a new miniature sisorid catfish from the Surma-Meghna River system in India and Bangladesh. Pseudolaguvia spicula can be distinguished from congeners in having a combination of: head width 19.2–22.6% SL, dorsal-fin spine length 11.6–14.3% SL, length of dorsal-fin base 13.2–15.9% SL, pectoral-fin spine length 15.7–17.4% SL, length of adipose-fin base 14.7–17.1% SL, pelvic-fin length 14.6–17.1% SL, body depth at anus 12.8–16.8% SL, caudal peduncle length 15.4–17.9% SL, caudal peduncle depth 7.9–9.6% SL, caudal-fin length 24.2–27.5% SL, snout length 48.6–51.9% HL, eye diameter 10.6–13.9% HL, 30–32 vertebrae, smooth anterior edge of dorsal-fin spine, thoracic adhesive apparatus reaching beyond base of last pectoral-fin ray, absence of pale y-shaped marking on dorsal surface of head and supraoccipital process, and indistinct, pale vertical bands on body.

Pseudolaguvia virgulata, a new South Asian sisorid catfish species, is described from the Barak River drainage in Mizoram, India. The new species can be distinguished from congeners in having a brown body with two or three narrow, pale longitudinal stripes and a pale Y-shaped marking on the dorsal surface of the head. Additional distinguishing characters from its congeners are a serrated anterior edge of the dorsal spine, the thoracic adhesive apparatus reaching beyond the base of the last pectoral-fin ray, head width, pectoral-fin length, length of dorsal-fin base, dorsal-spine length, body depth at anus, length of adipose-fin base, caudal peduncle length, caudal peduncle depth, snout length, interorbital distance, and total number of vertebrae.

Two new species of Glyptothorax are described from the rivers draining the Annam Cordilleras in central Vietnam. Glyptothorax filicatus n. sp. is distinguished from congeners in Indochina in having a diverging pattern of striae running along the edges of the central depression in the thoracic adhesive apparatus, and a combination of the following characters: dorsal spine length 13.7–15.1% SL, pectoral fin length 21.5–21.9% SL, length of adipose-fin base 13.3–15.0% SL, depth of caudal peduncle 8.4–8.8% SL, body depth at anus 15.1–16.0% SL, snout length 48.0–52.9% HL, eye diameter 8.9– 9.9% HL, anterior nuchal plate strongly demarcated in beige and caudal peduncle with a pale vertical band. Glyptothorax strabonis n. sp. is distinguished from congeners in Indochina in having a very small eye (6.2–6.5% HL), and a combination of the following characters: length of caudal peduncle 20.5–21.2% SL, depth of caudal peduncle 7.5–9.2% SL, body depth at anus 13.7–20.9% SL, head width 17.9–18.8% SL, presence of 14–16 serrae on posterior margin of pectoral spine, and coloration consisting of a dark-brown body with indistinct pale mid-lateral and mid-dorsal stripes.

Ompok supernus, a new species of silurid catfish is described from the Rungan River drainage in Kalimantan Tengah, southern Borneo. Ompok supernus can be distinguished from all Southeast Asian congeners, except for O. borneensis, O. fumidus and O. leiacanthus, in having a combination of a brown body without any prominent black humeral spot, the rictal lobes separated by a superficial groove extending from the corner of the mouth to the submandibular groove, a gape not reaching beyond the anterior border of the orbit, and 54–66 anal-fin rays. Ompok supernus differs from O. borneensis, O. fumidus and O. leiacanthus in having more dorsally-placed eyes, manifested in its smaller interorbital distance compared to the latter three species (42.6–48.7% HL vs. 49.1–59.5), and a combination of a mottled body and a rounded anterior profile of the lower jaw.

Nandus prolixus sp. nov. is described from the Sepilok River drainage in Sabah, northeastern Borneo. This species is distinguished from its only Sundaic southeastern Asian congener, N. nebulosus, in having a longer, more produced snout (25.7–30.6% HL vs. 18.5–26.1), more lateralline scales (33–37 vs. 24–34), more scales below the lateral line (12 vs. 10–11), fewer spines in the dorsal fin (XIV vs. XV–XVI), and fewer pectoral-fin rays (15–16 vs. 17–19). It differs from N. nandus (from India) in having fewer lateral-line scales (33–37 vs. 42–55), fewer scales above the lateral line (4–5 vs. 6–7), fewer scales below the lateral line (12 vs. 14–18), more dorsal spines (XIV vs. XII–XIII), and the absence (vs. presence) of a distinct dark spot at the base of the caudal peduncle. It differs from N. oxyrhynchus (from mainland southeastern Asia) in having a more slender body (body depth 37.6–40.5% SL vs. 41.3–44.1) and a less steeply sloping predorsal profile.

A new species of sisorid catfish, Pseudecheneis suppaetula, is described from tributaries of the Ganges River in India. Pseudecheneis suppaetula can be distinguished from congeners in having a combination of a long adipose-fin base (at least 2.0 times length of anal-fin base; 26.6–30.6% SL), small eye (8.1–8.3% SL), the presence of pale spots on the body, and the neural spines of the last 2–3 preanal and first 6–7 postanal vertebrae gradually increasing in height.

Akysis longifilis, new species, is described from the Sittang River drainage in Myanmar. It is a member of the A. variegatus species group and can be distinguished from congeners in the group (except for A. brachybarbatus, A. fuliginatus, A. pictus, A. prashadi, A. variegatus, A. varius and A. vespa) in having a smooth (vs. serrated) posterior edge of the pectoral spine. It is distinguished from A. brachybarbatus, A. fuliginatus, A. pictus, A. prashadi, A. variegatus, A. varius and A. vespa in having a unique combination of: length of adipose-fin base 25.7–31.1% SL, body depth at anus 9.7–13.6% SL, caudal peduncle length 18.3–23.2% SL, caudal peduncle depth 5.6–7.2% SL, head width 21.1–24.7% SL, nasal barbel length 67.4–96.4% HL, maxillary barbel length 123.2–159.6% HL, vertebrae 33–35, body with light saddle-shaped spots, and caudal fin forked.

The identity of South Asian riverine bagrid catfishes usually referred to as Mystus cavasius (Hamilton, 1822) is reviewed. Three species comprise what is currently understood as M. cavasius: M. cavasius s. str. from northern India, M. seengtee from southern India and a new species, M. falcarius, from the Salween and Irrawaddy river drainages in Myanmar and the shorter river drainages in southern Myanmar. Mystus seengtee is resurrected from synonymy with M. cavasius and both species are redescribed. The three species differ from other congeners with a long-based adipose fin in having a combination of a black spot in front of the dorsal-spine base, a dark humeral mark, a body without distinct midlateral stripes, very long maxillary barbels reaching to caudal-fin base, dorsal spine short and feebly serrate, tall dorsal fin, and 13ñ29 gill rakers. These species differ from each other in dorsal fin shape, shape of the predorsal profile, coloration, and number of rakers on the first gill arch.

Pterocryptis anomala (Herre, 1933) is resurrected from synonymy with P. cochinchinensis (Valenciennes, 1839) and redescribed in this study. This species of catfish from southern China and Hong Kong Special Administrative Region can be distinguished from congeners by the unique combination of the following characters: length of dorsal fin 7.9–10.1% SL, depth of caudal peduncle 7.2–9.7% SL, head length 16.6–20.7% SL, eye diameter 9.2–13.7% SL, dorsal-fin rays 3– 4, anal-fin rays 59–69, principal caudal rays 14–16, small conical genital papilla in both sexes, anal and caudal fins separated by a deep notch, narrow cheeks, circular eye and weakly contrasting mottled coloration. Characters for diagnosing Pterocryptis species are identified and discussed.

Two new species of sisorid catfish of the genus Pseudecheneis are described from tributaries of the Ganges River in Nepal: Pseudecheneis crassicauda and P. serracula. Pseudecheneis crassicauda can be distinguished from congeners by a unique combination of 38–39 vertebrae, caudal peduncle depth 6.0–6.6% SL, eye diameter 7.5–8.3% HL, length of adipose-fin base 20.3–24.3% SL, pelvic fins reaching the base of the first anal-fin ray, and the presence of pale spots on the body. Pseudecheneis serracula can be distinguished from congeners in having a unique combination of 36–38 vertebrae, strongly elevated neural spines of the last 2–3 preanal and first 6–7 postanal vertebrae, length of adipose-fin base 26.8–30.4% SL, pelvic fins reaching the base of the first analfin ray, and the presence of pale spots on the body.

Two new South Asian catfish species of the family Erethistidae, Pseudolaguvia inornata and Pseudolaguvia muricata, are described from the Brahmaputra and Feni River drainages in Bangladesh. Pseudolaguvia inornata from the Feni River drainage can be distinguished from congeners in having a uniform coloration with a pale mid-dorsal stripe and brown submarginal stripes on each lobe of the caudal fin, while P muricata from the Brahmaputra River drainage can be distinguished from congeners by its elongate dorsal and pectoral-fin spines.

Glyptothorax botius is revalidated from synonymy with G. telchitta. Both G. botius and G. telchitta are known from the Ganges River drainage in northeast India, and differ from congeners in the region in having a combination of large, prominent tubercles on the head and body, a thoracic adhesive apparatus without a median depression, and a very slender body and caudal peduncle. Glyptothorax botius was previously considered a synonym of G. telchitta, but differs from it in having a more rounded snout when viewed laterally, the presence (vs. absence) of dark saddles on the body, a thoracic adhesive apparatus with broader folds of skin, a longer adipose-fin base (12.0–16.4% SL vs. 9.5–11.5) and a more slender caudal peduncle (3.1–4.2% SL vs. 4.7–5.9). Both species are redescribed in this study, and neotypes are designated to fix their taxonomy.

The identity of the poorly known bagrid catfish Pseudomystus moeschii (Boulenger, 1890) is clarified and the species redescribed. Two new species of closely related bagrid catfishes are also described: Pseudomystus carnosus from the Way Seputih River drainage in the province of Lampung in the southern tip of Sumatra, and P. fumosus from the Pahang River drainage in eastern Peninsular Malaysia. Pseudomystus carnosus, P. fumosus and P. moeschii can be distinguished from congeners in having an enlarged posterior process of the post-temporal, presence of long hair-like epithelial projections on the skin and long tubular extensions of the sensory pores. Pseudomystus carnosus differs from the other two species in having a pointed (vs. rounded) tip of the nuchal shield, while P. fumosus differs from the other two species in having very well developed procurrent caudal rays which are sinuously curved along the anterior edges (vs. less developed procurrent caudal rays that slope evenly along the edges). A lectotype is designated for P. moeschii.

Pseudomystus stenogrammus, a new species of bagrid catfish, is described from the Barito River drainage of southern Borneo. The new species is distinguished from all congeners by its colour pattern.

A new species of bagrid catfish of the genus Rita is described from the Indus River drainage in South Asia. Rita macracanthus differs from all congeners in having a unique combination of the following characters: dorsal spine reaching to middle of adipose-fin base; pectoral-spine length 28.7 30.0% SL; depth of caudal peduncle 7.6 8.4% SL; maximum length of premaxillary tooth band 4.8 6.4 times its maximum width; eye diameter 6.9 8.7% HL; interorbital distance 39.4 44.1% HL; dorsal surface of head between eyes and supraoccipital covered with thin skin wherein the underlying bone is visible; two distinct vomerine tooth patches with rounded peg-like teeth. The new species has been identified up until now as Rita rita, but is distinguished from that species in having longer dorsal and pectoral spines, a more slender caudal peduncle, and a longer premaxillary tooth band.

Pareuchiloglanis macropterus new species, is described from the Salween River (Nujiang) and Irrawaddy River drainages in southern China, and P. rhabdurus new species, is described from the Red River (Song Hong) drainage in northern Vietnam. Pareuchiloglanis macropterus can be distinguished from congeners by the following unique combination of characters: prepelvic length 37.0 42.2% SL; length of adipose-fin base 31.8 37.0% SL (dorsal-fin base 3.3 3.5 times in adipose-fin base); caudal peduncle length 17.6 20.0% SL; caudal peduncle depth 6.8 7.4% SL (2.4 3.0 times in caudal peduncle length); body depth at anus 9.5 12.6% SL; snout length 50.3 56.5% HL; interorbital distance 24.6 30.2% HL; 41 42 vertebrae; pectoral fin reaching to pelvic-fin origin; ventral limit of gill opening to level of third or fourth pectoral-fin element; posterior base of adipose fin notched and separate from caudal fin; and presence of pale patches on body. Pareuchiloglanis rhabdurus can be distinguished from congeners chiefly by a slender body (8.7% SL) and caudal peduncle (4.2% SL; 4.2 times in caudal peduncle length), as well as a combination of the following characters: length of adipose-fin base 34.7% SL; dorsal to adipose distance 12.2% SL; caudal peduncle length 17.6% SL; snout length 57.0% HL; interorbital distance 25.5% HL; adipose and caudal fins separate; and ventral limit of gill opening to base of first pectoral-fin element.

Kryptopterus platypogon, a new species of silurid catfish is described from the Rajang River drainage in northern Borneo. Kryptopterus platypogon, together with K. hexapterus and K. cheveyi, can be distinguished from congeners by a combination of the absence of the dorsal fin, a stronglyarched dorsal profile with a pronounced nuchal concavity and palatal teeth in a single elliptical patch. Kryptopterus platypogon differs from K. hexapterus in having a more strongly-projecting lower jaw, larger eye (14.1% HL vs. 8.0 12.6), longer maxillary (135.6% HL vs. 40.0 120.4) and mandibular (119.3% HL vs. 32.3 80.0) barbels that are flattened and ribbon-like (vs. flattened, but ovoid in cross section), and more ventrally-placed eyes (about one quarter of the orbital margin visible when the head is viewed ventrally vs. orbital margin barely visible), and from K. cheveyi in having a strongly projecting lower jaw (vs. upper and lower jaws of equal length), more anal-fin rays (83 vs. 66 71), narrower head (8.6% SL vs. 9.7 12.3) and smaller eye (14.1% HL vs. 18.9 22.7).

Kryptopterus geminus, a new species of silurid catfish is described from the Bang Pakong, Mekong, Mae Khlong and Chao Phraya River drainages in mainland Southeast Asia. Kryptopterus geminus, together with K. cryptopterus, can be distinguished from congeners by the dorsal profile lacking a nuchal concavity and short maxillary barbels extending to the base of the pectoral fin. Kryptopterus geminus can be further distinguished from K. cryptopterus in having a narrower head (9.5– 12.0% SL vs. 12.2–14.2), longer anal fin (62.2–72.7% SL vs. 57.2–62.9) and snout (39.5–45.3% HL vs. 35.1–39.8), and more laterally-placed eyes (only ventral half, vs. ventral two-thirds, of the orbital margin visible when the head is viewed ventrally).

A new species of catfish in the genus Clarias is described from the Barito River drainage in southern Borneo. Clarias insolitus can be clearly distinguished from all other Southeast Asian Clarias species in having a long and thin anterior fontanel and hypertrophied sensory canal pores on the head and body that are easily visible to the naked eye. Additional diagnostic characters not unique to this species are a uniform violet-gray color without any white spots on body and prominent serrations on the anterior edge of the pectoral spine.

Acrochordonichthys gyrinus, a new species of akysid catfish belonging to the A. ischnosoma species group, is described from the Chao Phraya River drainage in Thailand. It can be distinguished from congeners by a concave posterior margin of the pectoral fin and the unique combination of the following characteristics: head depth 9.8–11.4% SL; dorsal to adipose distance 7.4–8.6% SL; body depth at anus 8.3–10.5% SL; maximum width of humeral process 16.3% its length; and anterior margin of anal fin and posterior margin of adipose fin straight. This species represents the northernmost distribution of the genus.