Species composition and diversity of fishes in the South China Sea, Area II: Sarawak, Sabah and Brunei Darussalam waters

The collaborative research on species composition and diversity of fishes in the Sabah and Sarawak waters was carried out by using otter-board trawling, through K.K. Manchong, including taxonomic survey for commercial coastal fishes landed in the markets of Sarikei, Bintulu, Miri, Labuan and Kota Kinabalu. Totally 518 species from 24 orders and 108 families were obtained. Hundred and three economic species were obtained from trawling survey and 106 species from the markets. The station point at St. 33 and 48 is the highest species richness, 69 and 70 species found. The highest CPUE were obtained at St. 44 and 48 (196 and 144 kg). Demersal species form main composition of the catches with the 9 dominant economic species. This trawling survey obtained few amount of 37 pelagic species. This survey also found the third record of Hapalogenys analis and Pomadasys auritus from the Southeast Asian waters

First cytogenetic study of the Somphong’s rasbora (Trigonostigma somphongsi) (Perciformes, Cyprinidae), a critically endangered species in Thailand

The first chromosome study of Trigonostigma somphongsi (Meinken,1958) from Thailand. Specimens were collected from Pak Phli District, Nakhornnayok Province, central Thailand. The mitotic chromosomes were directly prepared from kidney tissues of two males and two females. Conventional staining and Ag-NOR banding techniques were applied to stain the chromosomes. The results shown that diploid chromosome number of T. somphongsi was 2n=50, the fundamental numbers (NF) were 92 in both male and female. The types chromosomes consisted of 10 metacentric, 20 submetacentric, 12 acrocentric and 8 telocentric chromosomes. The result also exhibited that the interstitial nucleolar organizer regions (NORs) were clearly observed at the short arm of chromosome pair 2. The karyotype formula could be deduced as: 2n (diploid) 50=10m+20sm+12a+8t

Species Composition and Diversity of Fishes in the South China Sea, Area I: Gulf of Thailand and East Coast of Peninsular Malaysia

The collaborative research on species composition and diversity of fishes in the Gulf of Thailand and eastern Malay Peninsula was carried out by R. V. Pramong 4 in Thai waters and K.K. Manchong, K.K. Mersuji in Malaysian waters, through otter-board trawling surveys. Taxonomic surveys also done for commercial fishes in the markets of some localities. Totally 300 species from 18 orders and 89 families were obtained. Their diversity are drastically declined, compare to the previous survey from 380 species trawled. The station point of off Ko Chang, eastern Gulf of Thailand and off Pahang River shown significantly high diversity of fishes57 and 73 species found. Demersal species form the main composition of the catchs. The lizardfish Saurida undosquamis, S. miropectoralis, the bigeye Priacanthus tayenus and P. macracanthus, the rabbitfish Siganus canaliculatus and hairtail Trichiurus lepturus were the most abundant economic species found in mast of the sampling stations. Fishing efforts were 34 hours and 49 hours for the cruises I and II, with average catch per hour of 12.04 and 34.79 kg. respectively. The maximum catch per hour was 175.3 kg in Malaysian waters, the minimum was 4.33 kg in Thai waters. The average percentage of economic fishes is higher than that of trash fishes in Malaysian waters, it ranged from 55.45 to 81.92 %

Species Composition and Diversity of Fishes in the South China Sea, Area II: Sarawak, Sabah and Brunei Darussalam Waters

The collaborative research on species composition and diversity of fishes in the Sabah and Sarawak waters was carried out by using otter-board trawling, through K.K. Manchong, including taxonomic survey for commercial coastal fishes landed in the markets of Sarikei, Bintulu, Miri, Labuan and Kota Kinabalu. Totally 518 species from 24 orders and 108 families were obtained. Hundred and three economic species were obtained from trawling survey and 106 species from the markets. The station point at St. 33 and 48 is the highest species richness, 69 and 70 species found. The highest CPUE were obtained at St. 44 and 48 (196 and 144 kg). Demersal species form main composition of the catchs with the 9 dominant economic species. This trawling survey obtained few amount of 37 pelagic species. This survey also found the third record of Hapalogenys analis and Pomadasys auritus from the Southeast Asian waters

Macrobrachium spelaeus, a new species of stygobitic freshwater prawn from Thailand (Decapoda: Palaemonidae)

Cai, Yixiong, Vidthayanon, Chavalit (2016): Macrobrachium spelaeus, a new species of stygobitic freshwater prawn from Thailand (Decapoda: Palaemonidae). Raffles Bulletin of Zoology 64: 117-122, DOI: http://doi.org/10.5281/zenodo.450200

Exostoma effrenum Ng & Vidthayanon, 2014, new species

Exostoma effrenum, new species (Figs. 4, 5) Type material. Holotype: NIFI 4955, 51.3 mm SL; Thailand: Mae Hong Son Province, Mae La Noi District, Ping Noi stream close to Doi Om Phai in Chiang Mai Province, 18 ° 23 ' 43 "N 98 ° 7 ' 56 "E; Mae Hong Son Fisheries Station staff, December 1998. Paratypes: NIFI 3765 (2), 51.6 –65.0 mm SL; UMMZ 250050 (1), 54.2 mm SL; data as for holotype. Diagnosis. Exostoma effrenum is distinguished from congeners in having a combination of the following characters: eye diameter 11.5 –15.0% HL; head width 18.5–19.8 % SL; body depth at anus 10.5–12.4 % SL; length of adipose-fin base 25.8 –29.0% SL; adipose fin distinctly separate from upper procurrent caudal-fin rays; caudal peduncle length 20.5–21.3 % SL; caudal peduncle depth 5.1 –7.0% SL; forked caudal fin; 21–22 preanal vertebrae. Description. Morphometric data as in Table 2. Head and body broad, very strongly depressed, with paired fins greatly enlarged to form elongate ovoid adhesive disc with body. Rostral margin rounded in dorsal view, moderately curved in lateral view. Dorsal profile rising gently and evenly from anterior orbital margin to origin of dorsal fin, then sloping gently ventrally to end of caudal peduncle. Ventral profile flat to anal-fin base, then sloping gently dorsally to end of caudal peduncle. Anus and urogenital openings located at vertical through posterior margin of adpressed pelvic fin. Mouth ventrally directed with broad, thin and papillate lips. Most of premaxillary tooth patches exposed when mouth is closed. Lower lip with prominent labial fold bearing entire posterior margin, notched at insertions of inner mandibular barbels. Postlabial groove on lower jaw present, uninterrupted. Dorsal surface of head covered with conical, moderately dense tubercles. Jaw teeth distally flattened, oar-shaped and in two rounded triangular patches narrowly separated at midline on upper jaw. Teeth on lower jaw situated in two well-separated, roughly triangular patches. Palate edentulous. Eyes small, dorsolaterally situated, subcutaneous. Gill openings narrow, extending from base of first pectoralfin ray to level immediately dorsal to base of posteriormost pectoral-fin ray. Barbels in four pairs. Nasal barbel moderately long, reaching nearly to posterior orbital margin. Maxillary barbel flattened, with flap of skin fringing posterior margin; its tip pointed; ventral surface with numerous striae; extending beyond base of pectoral fin. Inner mandibular barbel slightly flattened, very short; originating from notch on posterior margin of lower lip. Outer mandibular barbel situated lateral to inner mandibular barbel; slightly flattened, reaching to two thirds of distance between its base and base of first pectoral-fin ray. Dorsal fin without spine, with i, 6 (4) rays; surfaces of fin rays covered with conical tubercles. Adipose fin with long base, posterior end separate from upper procurrent caudal-fin rays. Anal fin with ii, 4,i (4) rays. Caudal fin weakly forked, with i,7,7,i (4) rays; lower lobe very slightly longer than upper. Pelvic fin greatly enlarged, with convex distal margin and i, 5 (4) rays; first ray greatly flattened, with numerous striae on ventral surface; dorsal surfaces of fin rays covered with conical tubercles. Pectoral fin greatly enlarged, without spine and with i, 10,i (4) rays; first ray greatly flattened, with numerous striae on ventral surface. Dorsal surface of pectoral-fin rays covered with tubercles. Vertebrae 21 + 15 = 36 * (2), 22 + 14 = 36 (1) or 22 + 16 = 38 (1). Coloration. In 70 % ethanol: brown on dorsal and lateral surfaces of head and dorsal surface of body, dark yellow on ventral region. Dark yellow on lateral surfaces of body immediately dorsal and ventral to lateral myoseptum, giving impression of two diffuse brown lines on body: one on lateral myoseptum and another along inter-dorsal region and adipose-fin base. Myotomes along lateral surfaces of body with faint dark outlines. Dorsal fin brown; dorsal surfaces of pectoral and pelvic fins brown, with ventral surfaces of pectoral and pelvic fins dark yellow. Anal fin dark yellow. Base of caudal fin with darker, diffuse brown band contiguous with irregular, wshaped brown band on most of caudal fin. Dorsal surface of nasal and maxillary barbels brown, ventral surface dark yellow. Mandibular barbels dark yellow. In life (Fig. 5): Medium brown on dorsal and lateral surfaces of head and body, fading to tan on ventral surfaces. Numerous pale spots densely distributed over dorsal surfaces of head and predorsal region. Dorsolateral surface of body with two indistinct tan blotches: one below adipose-fin origin and another below middle of adipose-fin base. Dorsal, pectoral and pelvic fins with dusky fin rays and hyaline fin membranes. Base of caudal fin with gently crescentic dark brown bar; middle third of caudal fin with irregular, dark brown w-shaped band. Dorsal surface of nasal and maxillary barbels olive brown, ventral surfaces tan. Mandibular barbels tan. Distribution. This species is known from the upper reaches of the Ping River (one of two main tributaries of the Chao Phraya River) drainage in northwestern Thailand (Fig. 3). The record from the Doi Inthanon National Park in Chiang Mai Province, Thailand, is based on photographs of specimens (not preserved; Fig. 5) referable to this species we have examined. Etymology. The specific epithet comes from the Latin adjective effrenus, meaning unbridled. This is used in allusion to the condition of the adipose fin being distinctly separate from the upper principal caudal-fin rays in this species.Published as part of Ng, Heok Hee & Vidthayanon, Chavalit, 2014, A review of the glyptosternine catfish genus Exostoma Blyth 1860 from Thailand, with descriptions of two new species (Teleostei: Siluriformes), pp. 420-434 in Zootaxa 3869 (4) on pages 424-427, DOI: 10.11646/zootaxa.3869.4.6, http://zenodo.org/record/23083

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

Ng, Heok Hee, Vidthayanon, Chavalit (2014): A review of the glyptosternine catfish genus Exostoma Blyth 1860 from Thailand, with descriptions of two new species (Teleostei: Siluriformes). Zootaxa 3869 (4): 420-434, DOI: 10.11646/zootaxa.3869.4.

Exostoma berdmorei Blyth 1860

Exostoma berdmorei Blyth, 1860 (Figs. 1, 2) Exostoma berdmorei Blyth, 1860: 155 (type locality: Tenasserim, Myanmar); Hora & Silas, 1952: 27; Vidthayanon et al., 2005: 106 (text only). Exostoma labiatum (non M’Clelland)— Day, 1870: 525. Glyptosternum sp.— Hora, 1923: 43 Material examined. NIFI 0 894 (2), 34.3 –54.0 mm SL; Thailand: Mae Hong Son Province, Mae Sariang District, Huay Po. NIFI 1669 (1), 66.4 mm SL; Tak Province, Tha Song Yang District, Mae Jawang. ZRC 54293 (1), 53.4 mm SL; Thailand: Mae Hong Son Province, left side tributary of Mae Nam Pai, about 14 km N of Mae Sariang at bridge with road 108. Diagnosis. Exostoma berdmorei is distinguished from congeners in having a combination of the following characters: eye diameter 10.1–11.9 % HL; head width 18.3–21.1 % SL; pectoral-pelvic distance 32.8 –36.0% SL; dorsal-to-adipose distance 9.2–11.7 % SL; body depth at anus 11.0– 12.7 % SL; length of adipose-fin base 32.8–35.8 % SL; adipose fin adnate to upper procurrent caudal-fin rays; caudal peduncle length 16.4–19.6 % SL; caudal peduncle depth 9.2–9.7 % SL; weakly forked caudal fin; 22–23 preanal vertebrae. Description. Morphometric data as in Table 1. Head and body broad, very strongly depressed, with paired fins greatly enlarged to form elongate ovoid adhesive disc with body. Rostral margin rounded in dorsal view, moderately curved in lateral view. Dorsal profile rising gently and evenly from anterior orbital margin to origin of dorsal fin, then sloping gently ventrally to end of caudal peduncle. Ventral profile flat to anal-fin base, then sloping gently dorsally to end of caudal peduncle. Anus and urogenital openings located at vertical through posterior margin of adpressed pelvic fin. Mouth ventrally directed with broad, thin and papillate lips. Most of premaxillary tooth patches exposed when mouth is closed. Lower lip with prominent labial fold bearing entire posterior margin, notched at insertions of inner mandibular barbels. Postlabial groove on lower jaw present, uninterrupted. Jaw teeth distally flattened, oar-shaped, in two rounded triangular patches narrowly separated at midline on upper jaw. Teeth on lower jaw situated in two well-separated, roughly triangular patches. Palate edentulous. Eyes small, dorsolaterally situated, subcutaneous. Gill openings narrow, extending from base of first pectoralfin ray to level immediately dorsal to base of posteriormost pectoral-fin ray. Barbels in four pairs. Nasal barbel moderately long, reaching to middle of orbit. Maxillary barbel flattened, with flap of skin fringing posterior margin; its tip pointed; ventral surface with numerous striae; extending beyond base of pectoral fin. Inner mandibular barbel slightly flattened, very short; originating from notch on posterior margin of lower lip. Outer mandibular barbel situated lateral to inner mandibular barbel; slightly flattened, reaching to two-thirds of distance between its base and base of first pectoral-fin ray. Dorsal fin without spine, with i, 6 (4) rays. Adipose fin with long base, posterior end adnate to upper procurrent caudal-fin rays. Anal fin with ii, 4,i (4) rays. Caudal fin weakly forked, with i,7,7,i (4) rays; lower lobe slightly longer than upper. Pelvic fin greatly enlarged, with convex distal margin and i, 5 (4) rays; first ray greatly flattened and with numerous striae on ventral surface. Pectoral fin greatly enlarged, without spine and with i, 8,i (1), i, 9 (2) or i,l0 (1) rays; first ray greatly flattened and with numerous striae on ventral surface. Vertebrae 22 + 14 = 36 (2) or 23 + 14 = 37 (1). Coloration. In 70 % ethanol: brown on dorsal and lateral surfaces of the head and body, dark yellow on ventral region. Dorsal and caudal fins brown; dorsal surfaces of pectoral and pelvic fins brown, with light yellow ventral surfaces. Anal fin dark yellow. Dorsal surface of barbels brown, ventral surface dark yellow. Caudal fin with pale chevron-shaped band at base and broad, dark W-shaped band on most of middle. In life (Fig. 2): Olive brown on dorsal and lateral surfaces of head and body, fading to tan on ventral surfaces. Numerous pale spots densely distributed over dorsal surfaces of head and predorsal region. Dorsolateral surface of body with three indistinct tan-colored blotches: one below region between dorsal and adipose fins, second below adipose-fin origin, third below middle of adipose-fin base. Dorsal, pectoral and pelvic fins with dusky fin rays and hyaline fin membranes. Base of caudal fin with gently crescentic dark-brown bar; middle third of caudal fin with irregular, dark-brown w-shaped band. Dorsal surface of nasal and maxillary barbels olive brown, ventral surfaces tan. Mandibular barbels tan. Distribution. This species is known from the Salween River drainage in Myanmar and western Thailand (Fig. 3). It has been reported from the Sittang River drainage (Thomson & Page, 2006), but this awaits confirmation.Published as part of Ng, Heok Hee & Vidthayanon, Chavalit, 2014, A review of the glyptosternine catfish genus Exostoma Blyth 1860 from Thailand, with descriptions of two new species (Teleostei: Siluriformes), pp. 420-434 in Zootaxa 3869 (4) on pages 421-423, DOI: 10.11646/zootaxa.3869.4.6, http://zenodo.org/record/23083

Tetraodon palustris, a new freshwater pufferfish (Tetraodontiformes: Tetraodontidae) from the Mekong Basin of Thailand

Saenjundaeng, Pasakorn, Vidthayanon, Chavalit, Grudpun, Chaiwut (2013): Tetraodon palustris, a new freshwater pufferfish (Tetraodontiformes: Tetraodontidae) from the Mekong Basin of Thailand. Zootaxa 3686 (1): 77-84, DOI: 10.11646/zootaxa.3686.1.

Fishes of the Greater Mekong Ecosystem with Species List and Photographic Atlas

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/122721/1/MP 201.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/122721/2/MP 201sm.pdfDescription of MP 201.pdf : MP 201 high res.Description of MP 201sm.pdf : MP 201 lo res