Heok Hee Ng

AN ANNOTATED CHECKLIST OF THE NON-NATIVE FRESHWATER FISH SPECIES IN THE RESERVOIRS OF SINGAPORE

We have recorded 54 species of non-native or alien freshwater fishes from 14 of the 15 reservoirs in Singapore. 31 of these species are established and breeding in the reservoirs. Three species (Mystus wolffii, Amphilophus citrinellum, and Satanoperca jurupari) represent new alien records for Singapore.

The Second Ural Centrum in Siluriformes and Its Implication for the Monophyly of Superfamily Sisoroidea (Teleostei, Ostariophysi)

Abstract A well-developed second ural half-centrum is a peculiar characteristic of the caudal skeleton of certain siluriforms, not seen in other Recent ostariophysans. Although the character has been previously recorded in the literature, its exact taxonomic distribution, structure, ontogeny, and phylogenetic meaning within siluriforms are not yet determined. In this paper, the degree of development of the second ural half-centrum is surveyed across the order. The ontogeny of the relevant axial structures in the posterior region of the vertebral column is reported in representative siluriform taxa. The condition where the second ural centrum is well formed and forms a complete intervertebral joint anteriorly with the compound caudal centrum is considered derived within siluriforms, a character state homoplastic with the primitive state in more distant teleostean outgroups. Various catfishes display that derived condition, which is informative about relationships at different levels within the group. The most inclusive of those clades is the superfamily Sisoroidea, including the families Amblycipitidae, Akysidae, Sisoridae, Erethistidae, and Aspredinidae. The placement of the neotropical Aspredinidae into an otherwise exclusively Asian clade has important biogeographical implications and the structure of the second ural centrum provides additional support to that hypothesis. Based on the currently available knowledge on the relationships among catfishes, a well-developed second ural centrum is hypothesized to be a result of six different events in siluriforms.

Monophyly and phylogenetic relationships of the catfish genus Glyptothorax (Teleostei: Sisoridae) inferred from nuclear and mitochondrial gene sequences

Glyptothorax Blyth (1860) is the most species-diverse and widely-distributed genus in the Sisoridae, but few studies have examined monophyly of the genus and phylogenetic relations within it. We used the nuclear RAG2 gene and mitochondrial COI and Cyt b genes from 50 of the approximately 70 species to examine monophyly of Glyptothorax and phylogenetic relationships within the genus. Molecular phylogenetic trees were constructed using maximum parsimony, maximum likelihood and Bayesian inference methods. All methods strongly supported monophyly of Glyptothorax, with Bagarius as its sister group. Both analyses of two- and three-gene datasets recovered nine major subclades of Glyptothorax, but some internal nodes remained poorly resolved. The phylogenetic relationships within the genus and existing taxonomic problems are discussed.

Glyptothorax maceriatus , a new species of sisorid catfish (Actinopterygii: Siluriformes) from north-eastern India

Glyptothorax maceriatus, new species, is described from the Meghna-Surma River system in Mizoram, northeast India. It differs from most congeners in the Indian subcontinent in having thoracic adhesive apparatus with a narrow elliptic central depression that is almost enclosed posteriorly by skin ridges. The following combination of characters serve to distinguish it from congeners in the Indian subcontinent: nasal barbel not reaching anterior orbital margin; interorbital distance 27.0–31.4% HL; head length 23.7–25.3% SL; head depth 12.5–14.2 % SL; thoracic adhesive apparatus with narrow elliptic central depression that is almost enclosed posteriorly by skin ridges (striae) and with single, non-diverging series of striae running along its edges; width of adhesive apparatus 55.8–72.1% its length; unculiferous ridges of adhesive apparatus not extending anteriorly onto gular region; absence of striae on first pectoraland pelvic-fin elements; pectoral-fin length 20.7–24.9% SL; dorsal-spine length 13.0–17.1% SL; smooth posterior edge of dorsal spine; dorsal-to-adipose distance 17.8–23.6% SL; body depth at anus 11.3–13.8% SL; pelvic-fin length 15.9–19.1 % SL; length of anal-fin base 13.9–16.2% SL; caudal peduncle length 21.4–23.9% SL; and caudal peduncle depth 6.4–7.6% SL (3.1–3.4 times in its length).

Stingers in a strange land: South American freshwater stingrays (Potamotrygonidae) in Singapore

South American freshwater stingrays of the family Potamotrygonidae have long been popular worldwide as ornamentals in the aquarium trade. Despite this, there have so far not been any reported cases of their establishment elsewhere in the world. Here, we document the ocellate river stingray, Potamotrygon motoro, as having established itself in Singapore. This represents the first alien record of a South American freshwater stingray outside the Neotropics.

Pterocryptis buccata, a new species of catfish from western Thailand (Teleostei: Siluridae) with epigean and hypogean populations

Pterocryptis buccata sp. nov. is described from the vicinity of Sai Yok, Kanchanaburi Province, western Thailand. It can be distinguished from all other congeners by its prominent mandibular muscles causing the cheeks to appear inflated and the following unique combination of characters: 54–61 anal-fin rays, 7 pelvic-fin rays, 50–52 vertebrae, 4 mandibular barbels and vomerine teeth present in 2 separate patches. An achromatic population inhabits the Sai Yok Noi cave. This is the first report of a cavedwelling catfish from Southeast Asia.

A New Torrent Catfish from Western Thailand (Siluriformes: Amblycipitidae)

Abstract Amblyceps protentum is described herein as a new species of amblycipitid catfish from the Salween River drainage in western Thailand. It can be distinguished from Indochinese congeners except for A. kurzii by a more elongate, slender body most evident in the smaller body depth at anus (8.0–11.0% SL vs. 10.7–16.9) and caudal peduncle depth (8.0–10.3% SL vs. 10.1–15.9). It differs from A. kurzii in having a longer adipose-fin base (18.8–22.7% SL vs. 15.1–18.3) and larger eye (diameter 6.9–8.8% HL vs. 5.1–5.8). Amblyceps protentum is further diagnosed by the following combination of characters: predorsal length 24.1–28.9% SL, length of dorsal-fin base 10.5–13.2% SL, dorsal-to-adipose distance 26.3–32.2% SL; head width 12.1–15.0% SL, total vertebrae 41–42, an incomplete lateral line and deeply forked caudal fin with poorly-developed projections on proximal lepidotrichia of median rays. The taxonomic status of A. caecutiens and A. kurzii are discussed and a neotype designated for A. caecutiens. This neotype designation makes A. mucronatum a junior subjective synonym of A. caecutiens.

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.

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.

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.