Heok Hee Ng - Academia.edu (original) (raw)

Papers by Heok Hee Ng

Zootaxa, 2005

Two new species of sisorid catfish of the genus Pseudecheneis are described from tributaries of t... more 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.

Proc Acad Natur Sci Phila, 2008

Silurichthys ligneolus, a new species of silurid catfish, is described from blackwater habitats i... more Silurichthys ligneolus, a new species of silurid catfish, is described from blackwater habitats in southern Borneo. The new species can be distinguished from congeners in having a combination of: body depth at anus 9.1-11.0% SL, caudal peduncle depth 4.7-5.5% SL, eye diameter 6.7-9.8% HL, pelvic fins present, 44-45 anal-fin rays, 3-4 principal rays on the lower caudal-fin lobe, lower lobe of caudal fin indistinct, 46-48 vertebrae, one gill raker on the first branchial arch, and body uniformly brown. Based on the morphology of its caudal fin, S. ligneolus is hypothesized to be the sister taxon of S. sanguineus.

Pseudomystus funebris, a new species of bagrid catfi sh is described from blackwater habitats in ... more Pseudomystus funebris, a new species of bagrid catfi sh is described from blackwater habitats in southern Borneo. The new species can be distinguished from congeners except for P. heokhuii by its unique colour pattern of a pale midlateral stripe and pale oblique bands on the sides of the body. It is distinguished from P. heokhuii in having a shorter adipose-fi n base (14.2-17.7% SL vs. 18.2-22.8), more slender caudal peduncle (7.3-8. ) and larger eye (11.2-14.7% HL vs. 8.5-10.7) and a slightly convex (vs. evenly sloping) predorsal profi le.

Zootaxa, 2004

Pareuchiloglanis macropterus new species, is described from the Salween River (Nujiang) and Irraw... more 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.

Zootaxa, Nov 10, 2010

Amblyceps cerinum, a new South Asian amblycipitid catfish species, is described from the Brahmapu... more Amblyceps cerinum, a new South Asian amblycipitid catfish species, is described from the Brahmaputra River drainage in northern West Bengal, India. The new species can be distinguished from congeners in having a combination of upper jaw longer than lower, incomplete lateral line terminating beneath posterior insertion of dorsal fin, length of adipose-fin base 32.4-38.3% SL, caudal peduncle length 21.9-24.5% SL, caudal peduncle depth 9.2-11.2% SL, 41-44 post-Weberian vertebrae, posterior end of adipose fin separated from dorsal procurrent caudal-fin rays by distinct notch, and truncate caudal fin. The taxonomic status of A. tenuispinis is also discussed and a neotype designated for this species.

Proceedings of the Biological Society of Washington, 2003

Arius verrucosus is a new species from the Mekong River drainage in mainland Southeast Asia. It c... more Arius verrucosus is a new species from the Mekong River drainage in mainland Southeast Asia. It can be distinguished from other ariids in the region (Sunda shelf) in having the following combination of autapomorphies: dorsal surface of exposed neurocranium ornamented with numerous small tubercles which never coalesce to form irregular radial ridges in adults, pectoral spine extending to a vertical posterior to last dorsal-fin ray (19.6-23.4 %SL) and ornamentedwith randomly distributed small tubercles. Together with A. stormiz, it is distinguished from other ariids in the region by the following synapomorphies: laterosensory canal system forming a dense anastomosing network on dorsal surfaces of head and body with very long branches spanning at least middle third of flanks, and strongly flattened fin spines. Finally, a unique combination of the following characters further diagnoses it from other ariids in the region: strongly depressed head, strongly projecting shark-like snout partially exposing premaxillary teeth when mouth is closed, palatal teeth in four patches organized into two contiguous groups (separated by a wide medial gap) on each side of anterior part of palate, deeply notched posterior end of supraoccipital, lateral line curving dorsally at caudal-fin base, gill rakers absent on mesial aspect of first two gill arches, and head depth 15.5-16.7%SL.

Http Dx Doi Org 10 1643 Ci 08 113, Jun 5, 2009

Zootaxa, 2005

Two new South Asian catfish species of the family Erethistidae, Pseudolaguvia inornata and Pseudo... more 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.

Zoological Journal of the Linnean Society, 2012

This study re-examined the taxonomic status of the sisorid catfishes usually identified as Glypto... more This study re-examined the taxonomic status of the sisorid catfishes usually identified as Glyptothorax zanaensis using a combination of morphometric and molecular data. Our results resurrect Glyptothorax longinema from the synonymy of G. zanaensis, and we describe two previously unnamed species as Glyptothorax granosus sp. nov. and Glyptothorax fucatus sp. nov. All four species are diagnosed and described in detail. Truss-based morphometrics combined with principal component analysis (PCA) detected three principal components (PCs) that can explain 86% of the total variation amongst species, which mainly reflect the characteristics of body depth, related depth, adhesive apparatus length, pectoral-fin length, caudal peduncle length, and barbel lengths. We also generated a phylogenetic hypothesis of these species using concatenated mitochondrial cytochrome b and D-loop gene sequences. Molecular dating analysis revealed a rapid speciation of Glyptothorax in the south-eastern corner of the Qinghai-Xizang Plateau from the middle Pliocene to early Pleistocene. A key to identify the Glyptothorax species from the Salween River drainage is also provided.

Zootaxa, 2010

Pseudolaguvia virgulata, a new South Asian sisorid catfish species, is described from the Barak R... more 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.

Revue Suisse De Zoologie, 2004

Journal of Fish Biology, Oct 31, 2001

A new species of glyptosternine catfish, Oreoglanis infulatus, is described from the Lam River dr... more A new species of glyptosternine catfish, Oreoglanis infulatus, is described from the Lam River drainage in central Vietnam. The new species is distinguished from all its congeners by possessing the following combination of characters: a dark band running across the anal fin, a lunate and uniformly dark caudal fin, the lower lip lacking a medial notch and with a lobulate posterior margin, maxillary barbel with a rounded tip, length of caudal peduncle 19·0-22·6 %L S , depth of caudal peduncle 2·6-3·2 %L S , post-adipose distance 6·8-8·0 %L S , eye diameter 10·5-12·1 %L H , 12 principal caudal-fin rays. 2001 The Fisheries Society of the British Isles

Revista De Biologia Tropical, Sep 1, 1999

... UMMZ 186765, 3 ex., 85.5-164.3 mm SL; UMMZ 214485, 1 ex., 113.7 mm SL; Thailand: Ubon Ratchat... more ... UMMZ 186765, 3 ex., 85.5-164.3 mm SL; UMMZ 214485, 1 ex., 113.7 mm SL; Thailand: Ubon Ratchathani province, Khong Chiam District, Mun River at Ban Dan, 3 km upstream from confluence with Mekong River; RE Arden, 1 July 1975. ...

Ichthyological Exploration of Freshwaters, 1998

Ichthyological Exploration of Freshwaters, 2012

Glyptothorax scrobiculus, new species, is described from the Tuirial River and tributaries of the... more Glyptothorax scrobiculus, new species, is described from the Tuirial River and tributaries of the Tuivai River in Mizoram, northeast India. It differs from all congeners in having a furrow running along the entire length of the ventral surface of the pectoral spine. The significance of the furrow is briefly discussed, and it is thought to arise from the posterior expansion of the adhesive surface of the pectoral spine.

International Journal of Tropical Biology and Conservation, 1999

Zootaxa, 2005

Two new species of sisorid catfish of the genus Pseudecheneis are described from tributaries of t... more 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.

Proc Acad Natur Sci Phila, 2008

Silurichthys ligneolus, a new species of silurid catfish, is described from blackwater habitats i... more Silurichthys ligneolus, a new species of silurid catfish, is described from blackwater habitats in southern Borneo. The new species can be distinguished from congeners in having a combination of: body depth at anus 9.1-11.0% SL, caudal peduncle depth 4.7-5.5% SL, eye diameter 6.7-9.8% HL, pelvic fins present, 44-45 anal-fin rays, 3-4 principal rays on the lower caudal-fin lobe, lower lobe of caudal fin indistinct, 46-48 vertebrae, one gill raker on the first branchial arch, and body uniformly brown. Based on the morphology of its caudal fin, S. ligneolus is hypothesized to be the sister taxon of S. sanguineus.

Pseudomystus funebris, a new species of bagrid catfi sh is described from blackwater habitats in ... more Pseudomystus funebris, a new species of bagrid catfi sh is described from blackwater habitats in southern Borneo. The new species can be distinguished from congeners except for P. heokhuii by its unique colour pattern of a pale midlateral stripe and pale oblique bands on the sides of the body. It is distinguished from P. heokhuii in having a shorter adipose-fi n base (14.2-17.7% SL vs. 18.2-22.8), more slender caudal peduncle (7.3-8. ) and larger eye (11.2-14.7% HL vs. 8.5-10.7) and a slightly convex (vs. evenly sloping) predorsal profi le.

Zootaxa, 2004

Pareuchiloglanis macropterus new species, is described from the Salween River (Nujiang) and Irraw... more 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.

Zootaxa, Nov 10, 2010

Amblyceps cerinum, a new South Asian amblycipitid catfish species, is described from the Brahmapu... more Amblyceps cerinum, a new South Asian amblycipitid catfish species, is described from the Brahmaputra River drainage in northern West Bengal, India. The new species can be distinguished from congeners in having a combination of upper jaw longer than lower, incomplete lateral line terminating beneath posterior insertion of dorsal fin, length of adipose-fin base 32.4-38.3% SL, caudal peduncle length 21.9-24.5% SL, caudal peduncle depth 9.2-11.2% SL, 41-44 post-Weberian vertebrae, posterior end of adipose fin separated from dorsal procurrent caudal-fin rays by distinct notch, and truncate caudal fin. The taxonomic status of A. tenuispinis is also discussed and a neotype designated for this species.

Proceedings of the Biological Society of Washington, 2003

Arius verrucosus is a new species from the Mekong River drainage in mainland Southeast Asia. It c... more Arius verrucosus is a new species from the Mekong River drainage in mainland Southeast Asia. It can be distinguished from other ariids in the region (Sunda shelf) in having the following combination of autapomorphies: dorsal surface of exposed neurocranium ornamented with numerous small tubercles which never coalesce to form irregular radial ridges in adults, pectoral spine extending to a vertical posterior to last dorsal-fin ray (19.6-23.4 %SL) and ornamentedwith randomly distributed small tubercles. Together with A. stormiz, it is distinguished from other ariids in the region by the following synapomorphies: laterosensory canal system forming a dense anastomosing network on dorsal surfaces of head and body with very long branches spanning at least middle third of flanks, and strongly flattened fin spines. Finally, a unique combination of the following characters further diagnoses it from other ariids in the region: strongly depressed head, strongly projecting shark-like snout partially exposing premaxillary teeth when mouth is closed, palatal teeth in four patches organized into two contiguous groups (separated by a wide medial gap) on each side of anterior part of palate, deeply notched posterior end of supraoccipital, lateral line curving dorsally at caudal-fin base, gill rakers absent on mesial aspect of first two gill arches, and head depth 15.5-16.7%SL.

Http Dx Doi Org 10 1643 Ci 08 113, Jun 5, 2009

Zootaxa, 2005

Two new South Asian catfish species of the family Erethistidae, Pseudolaguvia inornata and Pseudo... more 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.

Zoological Journal of the Linnean Society, 2012

This study re-examined the taxonomic status of the sisorid catfishes usually identified as Glypto... more This study re-examined the taxonomic status of the sisorid catfishes usually identified as Glyptothorax zanaensis using a combination of morphometric and molecular data. Our results resurrect Glyptothorax longinema from the synonymy of G. zanaensis, and we describe two previously unnamed species as Glyptothorax granosus sp. nov. and Glyptothorax fucatus sp. nov. All four species are diagnosed and described in detail. Truss-based morphometrics combined with principal component analysis (PCA) detected three principal components (PCs) that can explain 86% of the total variation amongst species, which mainly reflect the characteristics of body depth, related depth, adhesive apparatus length, pectoral-fin length, caudal peduncle length, and barbel lengths. We also generated a phylogenetic hypothesis of these species using concatenated mitochondrial cytochrome b and D-loop gene sequences. Molecular dating analysis revealed a rapid speciation of Glyptothorax in the south-eastern corner of the Qinghai-Xizang Plateau from the middle Pliocene to early Pleistocene. A key to identify the Glyptothorax species from the Salween River drainage is also provided.

Zootaxa, 2010

Pseudolaguvia virgulata, a new South Asian sisorid catfish species, is described from the Barak R... more 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.

Revue Suisse De Zoologie, 2004

Journal of Fish Biology, Oct 31, 2001

A new species of glyptosternine catfish, Oreoglanis infulatus, is described from the Lam River dr... more A new species of glyptosternine catfish, Oreoglanis infulatus, is described from the Lam River drainage in central Vietnam. The new species is distinguished from all its congeners by possessing the following combination of characters: a dark band running across the anal fin, a lunate and uniformly dark caudal fin, the lower lip lacking a medial notch and with a lobulate posterior margin, maxillary barbel with a rounded tip, length of caudal peduncle 19·0-22·6 %L S , depth of caudal peduncle 2·6-3·2 %L S , post-adipose distance 6·8-8·0 %L S , eye diameter 10·5-12·1 %L H , 12 principal caudal-fin rays. 2001 The Fisheries Society of the British Isles

Revista De Biologia Tropical, Sep 1, 1999

... UMMZ 186765, 3 ex., 85.5-164.3 mm SL; UMMZ 214485, 1 ex., 113.7 mm SL; Thailand: Ubon Ratchat... more ... UMMZ 186765, 3 ex., 85.5-164.3 mm SL; UMMZ 214485, 1 ex., 113.7 mm SL; Thailand: Ubon Ratchathani province, Khong Chiam District, Mun River at Ban Dan, 3 km upstream from confluence with Mekong River; RE Arden, 1 July 1975. ...

Ichthyological Exploration of Freshwaters, 1998

Ichthyological Exploration of Freshwaters, 2012

Glyptothorax scrobiculus, new species, is described from the Tuirial River and tributaries of the... more Glyptothorax scrobiculus, new species, is described from the Tuirial River and tributaries of the Tuivai River in Mizoram, northeast India. It differs from all congeners in having a furrow running along the entire length of the ventral surface of the pectoral spine. The significance of the furrow is briefly discussed, and it is thought to arise from the posterior expansion of the adhesive surface of the pectoral spine.

International Journal of Tropical Biology and Conservation, 1999