Silurichthys exortivus, a new catfish (Teleostei: Siluridae) from eastern Borneo, Indonesia.

Silurichthys exortivus, a new species of silurid catfish, is described from the Mahakam River drainage in eastern Borneo. The new species can be distinguished from congeners in lacking a dorsal fin, having 4 (vs. 67) principal rays on the upper caudal-fin lobe and a combination of: body depth at anus 14.0% SL, caudal peduncle depth 5.1% SL, pelvic fins absent, 54 anal-fin rays, caudal fin with asymmetrical lobes (upper lobe 1.1 times longer than lower), 48 vertebrae, 1 gill raker on the first branchial arch, and a mottled brown body. Based on the reduced number of principal caudal-fin rays, S. exortivus, S. ligneolus and S. sanguineus are hypothesized to form an exclusively Bornean clade.

Pseudobagarius eustictus, a new species of catfish from northern Laos (Siluriformes: Akysidae).

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.

Description of Bagarius vegrandis, a new species of sisorid catfish from Indochina (Actinopterygii: Siluriformes), with notes on the identity of Bagarius bagarius.

Bagarius vegrandis, new species, is described from the Chao Phraya and Mekong river drainages. It differs from congeners in having a small maximum body size (to 220 mm SL vs. 520-1400 mm SL) and the adipose-fin origin markedly posterior to (vs. at vertical through or very slightly posterior to) the anal-fin origin. It further differs from congeners in having the following unique combination of characters: ovoid unculiferous plaques on dorsal surface of head, lateral margin of frontal not significantly deflected dorsally, eye diameter 11-15% HL, interorbital distance 23-28% HL, head width 18.3-22.3% SL, head depth 11.1-14.1% SL, filamentous extensions to first pectoral-fin element reaching to anus, dorsal spine width 10.6-13.9 times in its length, body depth at anus 8.7-12.0% SL, neural spines of the 4-6 vertebrae immediately anterior to adipose fin distally flattened but not forming series of prominent bumps along dorsal midline, length of adipose-fin base 10.8-13.0% SL, caudal-peduncle length 19.0-22.4% SL, caudal-peduncle depth 3.2-4.2% SL, 19-20 preanal vertebrae, and 39-40 total vertebrae. Bagarius bagarius (Hamilton, 1822) is demonstrated to be a species restricted to the Indian subcontinent (with Bagrus yarrelli Sykes, 1839, Pimelodus platespogon Valenciennes, in Jacquemont, 1839 and Pimelodus carnaticus Jerdon, 1849 as junior subjective synonyms) and Bagarius lica Volz, 1903 resurrected from synonymy with B. yarrelli as a valid species from Southeast Asia.

A new, uniquely patterned spiny eel (Teleostei: Mastacembelidae) from southern Borneo, Kalimantan Tengah, Indonesia.

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.

Leiocassis rudicula (Teleostei: Siluriformes: Bagridae), a new catfish from eastern Borneo.

A new species of bagrid catfish in the genus Leiocassis is described from the Mahakam River drainage in eastern Borneo. Leiocassis rudicula, new species, can be distinguished from congeners in having a unique combination of: distinct concavity at level of orbit in dorsolateral profile of head; tip of supraoccipital spine not reaching anterior nuchal plate element; smooth posterior margin of dorsal spine; presence of an irregular pale band on sides of body between dorsal and adipose fins; anal fin with narrow brown band across middle third of fin; narrow caudal-fin lobes with nearly straight posterior margins; snout length 36-40% HL; eye diameter 14-20% HL; head depth 17.6-20.0% SL; length of dorsal-fin spine 14.1-18.5% SL; length of pectoral-fin spine 15.1-17.7 %SL; dorsal-to-adipose distance 10.9-14.3% SL; body depth at anus 16.4-19.5% SL; length of adipose-fin base 18.9-24.1% SL; length of anal-fin base 18.8-22.6% SL; and caudal peduncle depth 9.1-10.9% SL. A revised key to the genus is also provided.

Pterocryptis subrisa, a new silurid catfish (Teleostei: Siluridae) from northeastern India.

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.

Exostoma ericinum, a new glyptosternine catfish from southwestern China (Teleostei: Siluriformes: Sisoridae).

A new species of glyptosternine catfish in the genus Exostoma is described in this study. The new species, E. ericinum, is known from the upper Dayingjiang (=Taping River) drainage in southwestern China and is distinguished from congeners in having an unique combination of the following characters: 42-44 vertebrae; parallel striae on anterolateral surfaces of lips and lower surface of maxillary barbel; interorbital distance 26-31% HL; preanal length 67.7-70.5% SL; body depth at anus 10.4-12.0% SL (1.4-1.9 times in caudal peduncle depth); length of adipose-fin base 39.5-43.0% SL; lacking an incision at posterior extremity of adipose-fin base; caudal peduncle length 23.2-26.2% SL; caudal peduncle depth 5.7-7.9% SL; and caudal-fin lobes with slightly concave posterior margin.

The Glyptothorax of the Bolaven Plateau, Laos (Teleostei: Sisoridae): new and endangered.

Glyptothorax forabilis, new species, and G. porrectus, new species, are described from the Bolaven Plateau in southern Laos. Both species closely resemble G. laosensis, but can be distinguished from it and other Indochinese congeners by combinations of color pattern, morphometry (with particular regards to the eye, body depth, and caudal peduncle) and thoracic adhesive apparatus morphology. Both species are endemic to the Bolaven Plateau, have a very limited distribution and are threatened by hydropower and agricultural activities.

The Glyptothorax of Sundaland: a revisionary study (Teleostei: Sisoridae).

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.

A new diminutive sisorid catfish (Actinopterygii: Siluriformes) from northeastern India.

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.

A new species of anguilliform catfish (Actinopterygii: Siluriformes: Bagridae) from Bangladesh and northeastern India.

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.

Clarias serniosus, a new walking catfish (Teleostei: Clariidae) from Laos.

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.

A review of the glyptosternine catfish genus Exostoma Blyth 1860 from Thailand, with descriptions of two new species (Teleostei: Siluriformes).

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, a new species of bagrid catfish (Actinopterygii: Siluriformes) from northeastern India.

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.

Glyptothorax igniculus, a new species of sisorid catfish (Teleostei: Siluriformes) from Myanmar.

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.

Glyptothorax radiolus, a new species of sisorid catfish (Osteichthyes: Siluriformes) from northeastern India, with a redescription of G. striatus McClelland 1842.

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 subcontinent 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, pectoral 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.

After eighty years of misidentification, a name for the glass catfish (Teleostei: Siluridae).

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.

Pseudolaguvia nubila, a new sisorid catfish (Teleostei: Sisoridae) from northeastern India.

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.

Ompok karunkodu, a new catfish (Teleostei: Siluridae) from southern India.

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.