Tropical Natural History 13(2): 77-85, October 2013 2013 by Chulalongkorn University Validation of Tetraodon barbatus Roberts, 1998, a Freshwater Pufferfish (Family Tetraodontidae) from the Mekong River PASAKORN SAENJUNDAENG1*, CHAIWUT GRUDPUN2 AND CHAVALIT VIDTHAYANON3 1Faculty of Applied Science and Engineering, Khon Kaen University, Nong Khai Campus, Nong Khai 43000, THAILAND 2Faculty of Agriculture, Ubon Ratchathani University, Ubon Ratchathani 34190, THAILAND 3Environment Division, Mekong River Commission Secretariat, Vientiane, LAO PDR * Corresponding Author: Pasakorn Saenjundaeng ([email protected]) Received: 16 March 2013; Accepted: 13 August 2013 Abstract.– The freshwater pufferfish, Tetraodon barbatus Roberts, 1998, previously considered as a synonym of Tetraodon cambodgiensis Chabanaud, 1923, is validated. It differs distinctly from T. cambodgiensis by the combination of characters of that its caudal peduncle is smooth without small spinules and the head is broader (head width at preorbital, post orbital and nape: 54.1–59.8, 69.1–77.8 and 76.5–86.8 % head length (HL), respectively, in T. barbatus vs. 48.7–53.3, 60.2–64.3 and 68.5–74.3 %HL, respectively, in T. cambodgiensis). KEY WORDS: Tetraodon barbatus, valid species, Mekong River and from the other places in the Mekong INTRODUCTION basin in Thailand, Laos and Cambodia. We also examined the syntype of T. cambodgiensis Freshwater pufferfish of the genus in the Museum National d' Histoire Tetraodon Linnaeus, 1758 are widely Naturelle (MNHN), Paris, France, and distributed in Southeast Asia (Kottelat, additionally collected new specimens of this 2001; Monkolprasit et al., 1997; Rainboth, species from Siem Reap and Stung Treng, 1996; Sontirat, 1989; Vidthayanon, 2008; Cambodia and Tram Chim, Tam Nong, Vidthayanon et al., 1997). Roberts (1998) Vietnam. Examination all of these reviewed the taxonomy of the freshwater specimens revealed that T. barbatus differs pufferfish genus Tetraodon from Mekong from T. cambodgiensis in some distinctive basin, and also described T. abei and T. characters, sufficient to conclude that T. barbatus as two new species. Subsequently, barbatus is a valid species of freshwater Kottelat (2001) considered T. barbatus as puffer fish from the Mekong basin distinct junior synonym of T. cambodgiensis. from T. cambodgiensis. The present study Recently, the authors have collected T. focuses on two aspects. The first re- barbatus specimens from the same localities describes the morphology of T. barbatus, as the holotype and paratype in Thailand whilst the second revalidates T. barbatus as a valid species based on the differences from T. cambodgiensis in terms of morphological features. 78 TROPICAL NATURAL HISTORY 13(2), OCTOBER 2013 MATERIALS AND METHODS Tetraodon barbatus: Roberts, 1998: 230, fig. 4 (type locality: Huay Huang, 30 km. West The normal shape of the specimens (the of Chiang Khan, Loei Province, Thailand) proportions of the body when not puffed up) Monotreta cambodgiensis: Rainboth, 1996: was used for the morphological study. Fin 227, fig. 215 ray counts and measurements were Monotrete cambodgiensis: Kottelat, 2001: manipulated with the left side of specimens. 166, fig. 478 Point to point measurements were carried Material examined.– 24 specimens (18 out with dial calipers, recording the data to adults and 6 juveniles). Mekong basin: the nearest 0.1 mm. Measurements of the KUMF 8801, 7, 86.4–96.2 mm SL, Ban Tha standard length (SL), total length, dorsal fin Lat, Amphoe Ban Phaeng, Nakhon Phanom base length, head length (HL), snout length, Province, 18 March 2012, P. Saenjundaeng; interorbital distance, eye diameter and KUMF 8802, 3, 60.1–72.8 mm SL, Ban Pha mouth width, and the pectoral, dorsal, anal Tang, Amphoe Sangkhom, Nong Khai and caudal fin ray counts followed that of Province, 26 June 2010, P. Saenjundaeng; Dekkers (1975). In addition, the internasal KUMF 8803, 1, 69.9 mm SL, Ban Kokmad, distance, interopercular distance, head Amphoe Chiang Khan, Loei Province, 4 May depths and head widths at the preorbital, 2012, P. Saenjundaeng; KUMF 8804, 1, postorbital and nape, interpectoral fin 105.2 mm SL, Ban Hat Hae, Amphoe Chiang distance, prepectoral, predorsal and preanal Khan, Loei Province, 3 April 2012, B. fin lengths, pectoral, dorsal and anal fin base Hinumca; KUMF 8805, 1, 136.2 mm SL, lengths, depth and width of body at middle Ban Pha Tang, Amphoe Sangkhom, Nong base of the dorsal fin, and the caudal Khai Province, 4 April 2012, P. peduncle length, depth and width were all Saenjundaeng; KUMF 8806, 3, 36.9–85.4 measured. The head subunit sizes were mm SL, Ban Pha Tang, Amphoe Sangkhom, calculated in terms of the percent ratio of Nong Khai Province, 6 May 2010, P. the HL (%HL). Meanwhile, the HL and Saenjundaeng; KUMF 8807, 2, 93.4 and 95.8 measurements of the body parts were mm SL, Huay Huang, Ban Najan, Amphoe calculated as a percent ratio of the SL Chiang Khan, Loei Province, 28 July 2012, (%SL). The freshwater pufferfish specimens P. Saenjundaeng; KUMF 8808, 2, 111.2 and reported in this study are deposited in 123.2 mm SL, Amphoe Chiang Khan, Loei Kasetsart University Museum of Fisheries Province, 28 July 2012, P. Saenjundaeng; (KUMF), National Inland Fisheries Institute UNMF 07715, 1, 78.8 mm SL, Mouth of (NIFI) and Ubon Ratchathani Natural Mun River, Ban Dan Mai, Amphoe Khong History Museum of Fisheries (UNMF). Chiam, Ubon Ratchathani Province, 3 March 1999, C. Grudpun; NIFI 04686, 2, 96.2 and 102.2 mm SL, Nam Ngeum, Vang Viang, Lao PDR, 11 October 2011, C. Vidthayanon; RESULTS NIFI 04685, 1, 124 mm SL, Stung Treng, Cambodia, 4 August 2007, C. Vidthayanon. Tetraodon barbatus Roberts, 1998 Diagnosis.– Tetraodon barbatus can be (Fig. 1a-d) differentiated from T. cambodgiensis in having the following characters: caudal SAENJUNDAENG ET AL. — VALIDATION OF TETRAODON BARBATUS FROM THE MEKONG RIVER 79 FIGURE 1. Fresh specimen of T. barbatus Roberts, 1998, KUMF 8808, 123.2 mm SL, Mekong river at Amphoe Chiang Khan, Loei Province: (a) lateral view, (b) dorsal view, (c) ventral view and (d) caudal peduncle without small spinules. peduncle without small spinules or prickles 34.2, snout length 46.9–54.4, slightly large (Fig. 1d), broader head (Table 1) (head width eye (diameter 15.2–20.1) protrudes laterally, at the preorbital, post orbital and nape of visible from the ventral side of head, 54.1–59.8, 69.1–79.7 and 76.5–86.8 %HL, interorbital distance 52.0–64.7; internasal respectively, in T. barbatus vs. 48.7–52.9, distance 33.5–41.5, preorbital head depth 60.2–67.6 and 68.5–75.0 %HL, respectively, 45.6–58.9, width 54.1–59.8, postorbital head in T. cambodgiensis). depth 56.9–70.1, width 69.1–79.7, head Description.– Elliptical body, dorsal profile depth at nape 63.2–76.5, width 76.5–86.8. In of head and body slightly convex, long %SL: head length 37.6–43.6, interpectoral blunted snout. In %HL: mouth width 25.2– fin distance 24.4–30.9, prepectoral fin length 80 TROPICAL NATURAL HISTORY 13(2), OCTOBER 2013 TABLE 1. Meristic counts and the morphometric measurements, in terms of the %HL and %SL, of the specimens of T. barbatus and T. cambodgiensis Tetraodon barbatus (n = 24) Tetraodon cambodgiensis (n = 9) Characters (Range and mean ± SD) (Range and mean ± SD) Morphometric measurement as % HL Mouth width 25.2–34.2 (28.2 ± 2.3) 25.8–31.9 (29.3 ± 2.1) Snout length 46.9–54.4 (51.6 ± 1.6) 46.9–51.3 (49.4 ± 1.7) Eye diameter 15.2–20.1 (17.7 ± 1.3) 12.9–17.0 (15.1 ± 1.2) Interorbital distance 52.0–64.7 (60.2 ± 3.3) 50.6–56.9 (53.7 ± 2.5) Internasal distance 33.5–41.5 (35.7 ± 2.0) 31.1–39.7 (35.1 ± 2.9) Head depth at preorbital 45.6–58.9 (52.9 ± 3.4) 43.9–50.5 (48.0 ± 2.3) Head width at preorbital 54.1–59.8 (56.9 ± 1.9) 48.7–52.9 (51.6 ± 1.4) Head depth at postorbital 56.9–70.1 (64.4 ± 4.0) 56.1–60.8 (58.4 ± 1.5) Head width at postorbital 69.1–79.7 (73.9 ± 2.9) 60.2–67.6 (64.0 ± 2.5) Head depth at nape 63.2–76.5 (72.0 ± 3.5) 62.3–67.6 (64.7 ± 2.0) Head width at nape 76.5–86.8 (81.3 ± 3.5) 68.5–75.0 (72.0 ± 2.3) Morphometric measurement as %SL Head length 37.6–43.6 (40.7 ± 1.6) 37.7–40.8 (39.2 ± 1.3) Interpectoral fin distance 24.4–30.9 (27.3 ± 1.7) 21.8–25.1 (23.7 ± 1.0) Prepectoral fin length 40.1–45.1 (42.5 ± 1.4) 38.1–42.4 (40.6 ± 1.3) Predorsal fin length 69.6–75.4 (72.4 ± 1.4) 69.6–73.4 (71.9 ± 1.1) Preanal fin length 74.8–82.5 (78.5 ± 2.0) 76.8–80.6 (78.7 ± 1.2) Pectoral fin base length 9.1–11.5 (10.5 ± 0.7) 9.6–11.5 (10.5 ± 0.6) Dorsal fin base length 9.0–11.8 (10.4 ± 0.7) 9.5–11.7 (10.7 ± 0.7) Anal fin base length 6.2–8.2 (6.9 ± 0.4) 6.4–8.4 (6.9 ± 0.6) Body depth at middle base of dorsal fin 18.5–21.5 (20.1 ± 1.0) 19.4–22.0 (20.3 ± 0.8) Body width at middle base of dorsal fin 16.5–21.5 (18.9 ± 1.5) 15.3–18.6 (17.2 ± 1.2) Caudal peduncle length 14.5–17.7 (16.0 ± 1.0) 15.8–18.2 (16.9 ± 0.9) Caudal peduncle depth 11.0–13.7 (12.3 ± 0.7) 11.9–14.1 (12.9 ± 0.8) Caudal peduncle width 10.9–14.6 (12.9 ± 1.0) 10.2–13.7 (11.8 ± 1.2) Meristic count Pectoral fin ray i-ii 20–23 i-ii 20–22 Dorsal fin ray i-ii 11–12 ii 12–13 Anal fin ray i 9–10 i-ii 9–10 Caudal fin ray ii 6 ii ii 6 ii 40.1–45.1, predorsal fin length 69.6–75.4, Fin ray counts: pectoral i-ii 20–23, dorsal i-ii preanal fin length 74.8–82.5, pectoral fin 11–12, anal i 9–10, caudal ii 6 ii base length 9.1–11.5, dorsal fin base length Colour.– Colour patterns of live specimens 9.0–11.8, anal fin base length 6.2–8.2, body of T. barbatus. Middle sized, round ocellus depth at middle of dorsal fin base 18.5–21.5, with dark center on flank and light margin width 16.5–21.5, caudal peduncle length surrounding. Ventral surface of body 14.5–17.7, depth 11.0–13.7, width 10.9–14.6. evidently white. Dorsal and lateral surfaces Covering area of spinules on dorsal surface yellow to brown background covered with between internasal to behind dorsal fin end, small, round scattered-black spots. Lower lip on lateral surface between nasal organ generally has three black marks: first on anterior margin and curve line behind dorsal middle part, two on lower lip sides. These fin end to anterior anal fin origin, on ventral marks visible from juvenile through adult surface between chin and anterior of vent. stages. Some adult T. barbatus did not have SAENJUNDAENG ET AL. — VALIDATION OF TETRAODON BARBATUS FROM THE MEKONG RIVER 81 three black marks on lower lip. Lower lip 8818, 1, 88.0 mm SL, Ubonrat Dam, Khon usually grey. Pectoral and anal fins white, Kaen Province, 28 February 2012, M. slightly hyaline. Dorsal and caudal fins are Singhabud; NIFI 01546, 5, 46.8–81.6 mm grey. SL, Ubonrat Dam, Khon Kaen Province, 13 Geographic distribution.– T. barbatus is February 1985, S. Soontornsathit; NIFI only known from the middle and lower 01148, 8, 89.8–103.2 mm SL, Ubonrat Dam, Mekong basin (Roberts, 1998). The data Khon Kaen Province, 8–11 August 1977, J. from the field trips in Mekong basin of Ratanathavee; KUMF 1658, 6, 67.2–88.9 Thailand revealed that T. barbatus is not only mm SL, Nampong Irrigation Dam, 30 km found in Mekong mainstream but also in its North of Khon Kaen, 23 March 1971, P. larger tributaries, especially in places with Wongrat and Party; KUMF 8819, 2, 85.0– rocky, sandy or muddy substrate. Moreover, 112.8 mm SL, Nam Pong river, Ban Hua T. barbatus inhabits rapids and is often found Dong, Tambon Ban Kham, Amphoe Nam in the same habitat as T. suvattii and T. Pong, Khon Kaen Province, 28 February baileyi. 2012, M. Singhabud; KUMF 8820, 1, 57.2 mm SL, Nam Pong river, Ban Kut Phang Comparative material Khruea, Tambon Tha Krasoem, Amphoe 1. Tetraodon cambodgiensis: (Syntype Nam Pong, Khon Kaen Province, 8 March plus eight specimens (8 adults and 1 2012, M. Singhabud; NIFI 00627, 2, 76.2 juvenile)). Syntype from Museum National d' and 87.6 mm SL, Lampao Dam, Kalasin Histoire Naturelle, Paris, with catalog Province, 25 February 1978, N. Sugomol; number MNHN 22-80 (Syntype of T. KUMF 8821, 6, 70.2–82.6 mm SL, Lampao cambodgiensis Chabanaud, 1923): 1, 141.1 Dam, Ban Tha Ruea, Amphoe Yang Talat, mm SL, Phnom Penh, Cambodia, 1921, A. Kalasin Province, 5 August 2012, P. Krempf; NIFI 04684, 2, 35.4 and 124.3 mm Saenjundaeng; KUMF 8822, 3, 71.0–81.0 SL, Stung Treng, Cambodia, 9–11 March mm SL, Chi river, Ban Pak Pla Khao, 2007, C. Vidthayanon; UNMF 07716, 5, Tambon Don Ong, Amphoe Pho Chai, Roi Et 127.9–144.8 mm SL, Tonle sap lake fishing Province, 29 April 2012, P. Saenjundaeng; area, Phsar Leu (fresh market), Siem Reap, KUMF 8823, 8, 70.2–109.4 mm SL, Chi Cambodia, 11 March 2008, C. Grudpun; river, Ban Pak Pla Khao, Tambon Don Ong, NIFI 04683, 1, 115.8 mm SL, Tram Chim, Amphoe Pho Chai, Roi Et Province, 27 Tam Nong, Vietnam, 28 May 2007, C. March 2012, S. Juntarasombat; KUMF 8824, Vidthayanon; NIFI 04694, 1, 109.6 mm SL, 6, 61.2–96.2 mm SL, Chi river, Ban Non Tram Chim, Tam Nong, Vietnam, 12 July Krayom, Tambon Pho Chai, Amphoe Kok 2007, C. Vidthayanon. Pho Chai, Khon Kaen Province, 26 February 2. Tetraodon cochinchinensis: (55 2012, M. Decha; KUMF 8825, 1, 67.8 mm samples; 33 adults and 22 juveniles). NIFI SL, Chi River, Tambon Tha Phra, Amphoe 01544, 1, 48.2 mm SL, Ubonrat Dam, Khon Mueang, Khon Kaen Province, 6 March Kaen Province, 13 February 1985, S. 2012, M. Singhabud; KUMF 1586, 2, 66.9 Soontornsathit; NIFI 03304, 1, 84.9 mm SL, and 88.2 mm SL, Kwan Payao, 5 March Ubonrat Dam, Khon Kaen Province, 1–5 1924, H.M. Smith; KUMF 1656, 1, 54.3 mm June 1987, P. Sodsook; NIFI 01520, 1, 64.8 SL, Kwan Payao, 21 October 1964, K.F. mm SL, Ubonrat Dam, Khon Kaen Province, Lagler and Party. 12 February 1985, S. Soontornsathit; KUMF 82 TROPICAL NATURAL HISTORY 13(2), OCTOBER 2013 DISCUSSION upper part of the body without spots, yellow ventral part and yellow or ruddy fins. Bleeker Roberts (1998) accepted T. cambodgiensis (1852) redescribed T. leiurus, based on 11 and T. cochinchinensis as synonyms of T. specimens from Java, Sumatra and Borneo leiurus. The data from the original (five specimens of syntypes and six new description of T. leiurus in Bleeker (1851) specimens from Sumatra and Borneo), gave the description of this species based on describing them as having a dark green body five specimens of 60-98 mm total length, covered with round green spots (except the collected from the sea and mouth of the river trunk), and a yellow or bronze ventral part. in Batavia (or Jakarta, Indonesia). The colour The first illustrated picture of Crayacion (= patterns were described as: dark and ruddy Tetraodon) leiurus by Bleeker (1865) also FIGURE 2. Preserved specimens of Tetraodon cambodgiensis Chabanaud, 1923, (a, b) syntype, MNHN 22- 80, 141.1 mm SL, Phnom Penh, Cambodia, showing the (a) lateral view and (b) dorsal view; (c–e) NIFI 04684, 124.3 mm SL, Stung Treng, Cambodia, showing the (c) lateral view, (d) dorsal view and (e) upper part of caudal peduncle with small spinules. SAENJUNDAENG ET AL. — VALIDATION OF TETRAODON BARBATUS FROM THE MEKONG RIVER 83 FIGURE 3. The juvenile stage of (a–c) T. cambodgiensis and (d–f) T. barbatus: (a–c) NIFI 04684 T. cambodgiensis, 35.4 mm SL, Stung Treng, Cambodia, showing the (a) lateral view, (b) dorsal view and (c) ventral view; (d–f) KUMF 8806 T. barbatus, 36.9 mm SL, Ban Pha Tang, Amphoe Sangkhom, Nong Khai Province, showing the (d) lateral view, (e) dorsal view and (f) ventral view. gave a description, based on 19 specimens, of covering area of spinules in T. cambodgiensis a dark green body covered with round black is between the internasal and the upper part or dark green spots except for the trunk. The of caudal peduncle and so is evidently illustrated picture of C. (or Tetraodon) different from the covering area of spinules leiurus shows that the surface of the body has in C. (or Tetraodon) leiurus (Bleeker, 1865). no ocellus and the covering area of spinules Accordingly, it can be concluded that T. was between the internasal and the end of cochinchinensis and T. cambodgiensis are dorsal fin base. The colour patterns of T. separate and valid species of freshwater leiurus in Bleeker (1851) differ from those in pufferfish. Bleeker (1852, 1865) in the presence of a T. barbatus differs from T. dark or ruddy body without spots. Of course cochinchinensis in having a longer snout this discrepancy in colour appearance might (snout length 49.2–54.4 %HL in T. barbatus be an artifact caused by inappropriate sample vs. 43.5–48.7 %HL in T. cochinchinensis). preservation, but in general the descriptions While T. cambodgiensis can be distinguished in Bleeker (1851, 1852 and 1865) from T. cochinchinensis by having a slender demonstrated that the colour patterns of T. body with a slightly longer snout (snout leiurus are different from T. cambodgiensis length 46.9–51.3 %HL in T. cambodgiensis and T. cochinchinensis, which are found in vs. 43.5–48.7 %HL in T. cochinchinensis) the Mekong basin, in terms of having no and the caudal peduncle is covered with large ocellus on the flank. Additionally, the many spinules. 84 TROPICAL NATURAL HISTORY 13(2), OCTOBER 2013 T. barbatus was considered as a synonym ACKNOWLEDGEMENTS of T. cambodgiensis by Kottelat (2001) because they are similar in shape and colour This study was supported by a research patterns. However, examination of the fund from Khon Kaen University, Nong syntype of T. cambodgiensis (Fig. 2a–b) and Khai Campus. The authors thank Dr. Patrice the specimens from Stung Treng (Fig. 2c–e), Pruvost of the Museum National d' Histoire Siem Reap, Cambodia and Tram Chim, Tam Naturelle (MNHN) Paris, France for his Nong, Vietnam, revealed that the upper part profitable assistance and preparing the of the caudal peduncle has many small syntype specimen of Tetraodon cambodgiensis. spinules. On the other hand, the caudal The authors also thank all the fishermen for peduncle of T. barbatus specimens is smooth their help in field collections. without any tiny spinules. The distribution of spinules on the head and the body has been LITERATURE CITED used for species identification in the genus Lagocephalus (Mohsin and Ambak, 1996) Bleeker, P. 1851. Over drie nieuwe soorten van and it is evidently different between the Tetraödon van den Indischen Archipel. genera Takifuku and Tetractenos (Matsuura, Natuurkundig Tijdschriftvoor NederlandschIndië, 2001). 1: 96-97. Bleeker, P. 1852. Zesde bijdrage tot de kennis der With respect to the morphometric data of ichthyologische fauna van Borneo. Visschen van the head width at the preorbital, postorbital Pamangkat, Bandjermassing, Praboekarta en and nape, the head of T. barbartus is broader Sampit. Natuurkundig Tijdschriftvoor Neder- than in T. cambodgiensis (head width at landsch Indië, 3: 407-442. preorbital, post orbital and nape: 54.1–59.8, Bleeker, P. 1865. Atlas ichthyologique des Indes Orientales Néêrlandaises, publié sous les auspices 69.1–79.7 and 76.5–86.8 %HL, respectively, du Gouvernement colonial néêrlandais. Vol. V. in T. barbatus vs. 48.7–52.9, 60.2–67.6 and Baudroies, Ostracions, Gymnodontes, Balistes. 68.5–75.0 %HL, respectively, in T. Atlas Ichthyologique, 5: 1-152. cambodgiensis). The juvenile stage of T. Dekkers, W.J. 1975. Review of the Asiatic freshwater puffers of the genus Tetraodon Linnaeus, 1758 cambodgiensis has a light grey lower lip and (Pisces, Tetraodontiformes, Tetraodontidae). grey chin, lateral sides of trunk and ventral Bijdragen Tot De Dierkunde, 45: 87-142. surface of the tail. The ocellus has no white Kottelat, M. 2001. Fishes of Laos. WHT Publications margin (Fig. 3a–c). In contrast, the juvenile (Pte) Ltd. Sri Lanka. 198 pp. stage of T. barbatus exhibits three black Matsuura, K. 2001. Family Tetraodontidae. In: Carpenter, K.E. and Niem, V.H. (eds). FAO marks on the lower lip, a clear white ventral Species Identification Guide for Fishery Purposes. surface of the body and the ocellus has a The Living Marine Resources of the Western white margin (Fig. 3d–f). Consequently, it Central Pacific. Volume 6. Bony Fishes Part 4 can be concluded that T. barbatus is a valid (Labridae to Latimeriidae), Estuarine Crocodiles, SeaTurtles, Sea Snakes and Marine Mammals. species of freshwater pufferfish in the FAO, Rome. pp. 3954-3957. Mekong basin. Mohsin, A.K.M. and Ambak, M.A. 1996. Marine Fishes and Fisheries of Malaysia and Neighbouring Countries. Universiti Pertanian Malaysia Press. Selangor Darul Ehsan. 655 pp. Monkolprasit, S., Sontirat, S., Vimollohakarn, S. and Songsirikul, T. 1997. Checklist of Fishes in Thailand. Office of Environmental Policy and Planning, Bangkok, Thailand. 353 pp. SAENJUNDAENG ET AL. — VALIDATION OF TETRAODON BARBATUS FROM THE MEKONG RIVER 85 Rainboth, W.J. 1996. Fishes of the Cambodian Sontirat, S. 1989. Four new species of freshwater fishes Mekong. FAO Species Identification Field Guide from Thailand. Kasetsart Journal (Natural Science), for Fishery Purposes. Mekong River Commission. 23: 98-109. 265 pp. Vidthayanon, C. 2008. Field Guide to Fishes of the Roberts, T.R. 1998. Freshwater fugu or pufferfishes of Mekong Delta. Mekong River Commission. the genus Tetraodon from the Mekong basin, with Vientiane. 288 pp. description of two new species. Ichthyological Vidthayanon, C., Karnasuta, J. and Nabhitabhata, J. Research, 45: 225-234. 1997. Diversity of Freshwater Fishes in Thailand. Office of Environmental Policy and Planning. Bangkok. 102 pp.