A New Opisthotropis (Serpentes: Colubridae: Natricinae) from Northeastern Thailand

Current Herpetology 26(1): 35 40, June 2007 2007 by The Herpetological Society of Japan A New Opisthotropis (Serpentes: Colubridae: Natricinae) from Northeastern Thailand BRYAN L. STUART 1,2 * AND YODCHAIY CHUAYNKERN 3,4 1 Department of Zoology, The Field Museum, 1400 South Lake Shore Drive, Chicago, Illinois 60605 2496, USA 2 Museum of Vertebrate Zoology, University of California, Berkeley, California 94720 3160, USA 3 Thailand Natural History Museum, National Science Museum, Technopolis, Khlong 5, Khlong Luang, Pathum Thani 12120, THAILAND 4 Reptiles et Amphibiens, Département de Systématique et Evolution, Muséum national d Histoire naturelle, 25 rue Cuvier, 75005, Paris, FRANCE Abstract: A new species of the aquatic natricine colubrid snake genus Opisthotropis is described based on a single specimen from Nong Khai Province, northeastern Thailand. The new species is distinguished from other Opisthotropis by the combination of having smooth scales on the body and tail, 15 dorsal scale rows throughout the body, the fourth supralabial in contact with the eye, the posterior pair of chin shields longer than the anterior pair, and a glossy black dorsum with yellow spots. Key words: New species; Opisthotropis; Phu Wua Wildlife Sanctuary; Thailand INTRODUCTION The natricine colubrid snake genus Opisthotropis Günther, 1872 contains approximately 15 species in Southeast Asia, distributed across the mainland to the Philippines and the Ryukyu Archipelago of Japan (Brown and Leviton, 1961; Orlov et al., 1998; Ota, 2004). All are aquatic and live in flowing streams. Some species of Opisthotropis have been infrequently encountered by herpetologists and are known only from very few specimens (Pope, 1935; Brown and Leviton, 1961; Taylor, 1965; Rasmussen, 1982; Cox, 1991; Stuebing and Inger, 1999; * Corresponding author. Tel: +1 312 665 7673; Fax: +1 312 665 7932; E-mail address: bstuart@fieldmuseum.org Ota, 2004). The monophyly of Opisthotropis has not been tested and the genus may not represent a natural group (Brown and Leviton, 1961). Opisthotropis closely resembles the aquatic natricine genus Parahelicops Bourret, 1934 (see Stuart, 2006), and some authors treat Parahelicops as a junior synonym of Opisthotropis (e.g., Smith, 1943; Brown and Leviton, 1961; Zhao et al., 1978; Cox, 1991, Cox et al., 1998). This taxonomic arrangement is followed here for convenience, pending phylogenetic analysis. Three species of Opisthotropis are currently known from Thailand, each from only one to three specimens: Opisthotropis boonsongi (Taylor & Elbel, 1958) from Loei Province in northeastern Thailand, O. praemaxillaris (Angel,

36 Current Herpetol. 26(1) 2007 FIG. 1. Map of Indochina showing location of Phu Wua Wildlife Sanctuary, Nong Khai Province, Thailand (star), where the unique specimen of an undescribed Opisthotropis was collected. the extreme northeastern corner of Thailand on the Khorat Plateau, near to the Mekong River and border with Laos (Fig. 1). The sanctuary is dominated by lowland evergreen forest with large sandstone outcrops (Fig. 2), and is the type locality of the draconine agamid lizard Mantheyus phuwuanensis (Manthey & Nabhitabhata, 1991), known only from the sanctuary and a second locality in adjacent Laos (Manthey and Nabhitabhata, 1991; Ananjeva and Stuart, 2001). During the course of our survey, we obtained a single specimen of a remarkably spotted, aquatic natricine that agrees with Smith s (1943: 330 331) morphological definition of the genus Opisthotropis. Herein, we describe this specimen as a new species. MATERIALS AND METHODS FIG. 2. View overlooking Phu Wua Wildlife Sanctuary, Nong Khai Province, Thailand. The Mekong River is faintly visible in the background as a white line at the base of the mountains, which are in Laos. 1929) from Chiang Mai Province in northern Thailand, and O. spenceri Smith, 1918 from Lampang Province in northern Thailand (Taylor, 1965; Rasmussen, 1982; Cox 1991; David et al., 2004). We conducted a brief survey of amphibians and reptiles in northeastern Thailand at Phu Wua Wildlife Sanctuary, Nong Khai Province, during September 2004 under the auspices of the Thailand Natural History Museum. Phu Wua Wildlife Sanctuary lies in The specimen was caught in the field by hand, preserved in 10% buffered formalin, and later transferred to 70% ethanol. Tissue samples were taken by preserving pieces of liver in 95% ethanol and 20% DMSO-salt saturated storage buffer before the specimen was fixed in formalin. The specimen was deposited in the Thailand Natural History Museum (THNHM) and cross-cataloged at the Field Museum of Natural History (FMNH). Comparative material was examined in the holdings of the Muséum national d Histoire naturelle (MNHN), Museum of Vertebrate Zoology, University of California, Berkeley (MVZ), and FMNH. Data for O. guangxiensis were taken from Zhao et al. (1978, 1998). Data for O. kikuzatoi were taken from Okada and Takara (1958), Toyama (1983), and Hidetoshi Ota s unpublished observation. Ventral scales were counted following Dowling (1951) and dorsal scale rows were counted at anterior neck, midbody, and anterior to cloaca. Hemipenial morphology was described following Dowling and Savage (1960). Measurements were made after preservation with a soft measuring tape to the nearest mm.

STUART & CHUAYNKERN NEW SNAKE FROM THAILAND 37 Opisthotropis maculosus, sp. nov. Figs. 3 5 Holotype Adult male, THNHM 05343/FMNH 265798 (deposited at THNHM), Thailand, Nong Khai Province, Boong Klar District, Phu Wua Wildlife Sanctuary, at marker 027 on footpath to Lad Phleuy Waterfall, 18 14'31.0''N 103 57'44.5''E, 190 m asl; Coll. Yodchaiy Chuaynkern, Chatchay Chuechat, Sunchai Makchai, and Bryan L. Stuart, 7 September 2004. FIG. 3. Dorsal view of holotype of Opisthotropis maculosus sp. nov. (THNHM 05343; total length= 520 mm) prior to preservation. Diagnosis An Opisthotropis having all scales smooth; 15 : 15 : 15 dorsal scale rows; fourth supralabial in contact with eye; posterior pair of chin shields longer than anterior pair; glossy black dorsum with single yellow spot on each scale, the yellow spot becoming larger on sides of body. Description of holotype Head small, indistinct from neck. Eye small, pupil round. Nostril directed dorsally. Rostral broader than deep, visible from above; nasal weakly divided, in contact with first two supralabials; two internasals narrowed anteriorly, in contact with rostral; one prefrontal, more than twice as broad as long; frontal about as broad as long, about equal to its distance from snout tip, equal to length of the suture of the parietals, about half the length of the parietals; one loreal, longer than deep, not in contact with internasals; one preocular; two postoculars, about equal in size; one supraocular, about twice as long as broad; eight supralabials on both sides, the fourth touching the eye, the fifth prevented from touching the eye by the lower postocular, the seventh the FIG. 4. Ventral view of holotype of Opisthotropis maculosus sp. nov. (THNHM 05343; total length= 520 mm) prior to preservation. FIG. 5. Dorsal (above) and lateral (below) views of head of holotype of Opisthotropis maculosus sp. nov. (THNHM 05343).

38 Current Herpetol. 26(1) 2007 largest; 1+1 temporals on both sides; eight infralabials on left, nine on right, the first five touching anterior chin shield, the fifth touching posterior chin shield; posterior pair of chin shields longer than anterior pair; body scales in 15 : 15 : 15 rows; all scales smooth; no apical pits on scales; small bumps scattered on surface of anterior and posterior chin shields; two pre-ventrals; 182 ventrals; 67 paired subcaudals; anal plate divided; everted hemipenes single in form, cylindrical, extending to level of 12 th subcaudal; sulcus spermaticus simple, extending to apical tip; basal area naked, remainder of hemipenes uniformly ornamented with spines. Snout-vent length 410 mm, tail length 110 mm. Color in life Eye black; scales on top of head glossy black with scattered yellow flecking near sutures; labials yellow with black on sutures; chin shields yellow; body and tail glossy black above, with single yellow spot on each scale, the yellow spot becoming larger on sides of body, with first three rows of dorsal scales having more yellow than black; ventrals and subcaudals yellow with black anterior and lateral margins. Color in preservative Black fades to dark grey-brown; yellow fades to creamy-yellow. Comparisons Four other species of Opisthotropis also have 15 mid-body scale rows, O. annamensis (Bourret, 1934), O. guangxiensis Zhao, Jiang & Huang, 1978, O. jacobi Angel & Bourret, 1933, and O. kikuzatoi (Okada & Takara, 1958), with remaining species having 17 or 19 mid-body scale rows (Günther, 1872; Pope, 1935; Bourret, 1936; Smith, 1943; Orlov et al., 1998; Taylor and Elbel, 1958; Zhao et al., 1998). Opisthotropis maculosus differs from O. annamensis by having 15 anterior body scale rows (17 anterior body scale rows in annamensis), smooth scales (median body rows feebly keeled anteriorly and strongly keeled posteriorly, tail scales very strongly keeled in annamensis), and a distinctly spotted dorsum (checkered dorsal pattern with an irregular, anterior dorsolateral stripe in annamensis). Opisthotropis maculosus differs from O. guangxiensis by having 15 anterior body scale rows (17 anterior body scale rows in guangxiensis), the fourth supralabial in contact with eye (fifth and sixth in guangxiensis), and a distinctly spotted dorsum without banding (up to 40 orange or orange-yellow bands bordered in black on dorsum in guangxiensis). Opisthotropis maculosus differs from O. jacobi by having a distinctly spotted dorsum (uniformly dark in jacobi), two postoculars (one in jacobi), the fourth supralabial in contact with eye (fourth and fifth in jacobi), and posterior pair of chin shields longer than anterior pair (reverse condition in jacobi). Opisthotropis maculosus differs from O. kikuzatoi by having smooth scales on tail (keeled scales on tail in kikuzatoi), posterior pair of chin shields longer than anterior pair (anterior pair as long as (see photograph in Ota and Mori [1985]) or longer than posterior pair in kikuzatoi), and yellow spot in each black dorsal scale throughout length of body (yellow spot in every third or fourth row of dorsal scales, distinctly visible only on anterior half of body in kikuzatoi). Etymology The specific epithet maculosus (L.) for spotted refers to the distinctive dorsal pattern of the new species. Suggested Thai name Ngu Lai So Chut Lueng Suggested English name Yellow Spotted Mountain Stream Snake Distribution, natural history, and behavior Opisthotropis maculosus is currently known only from the holotype specimen collected at Phu Wua Wildlife Sanctuary, Nong Khai Province, northeastern Thailand (Figs. 1 and 2). The holotype was swimming at night (1930 h)

STUART & CHUAYNKERN NEW SNAKE FROM THAILAND 39 during heavy rainfall in 5 cm of rainwater flowing swiftly through a temporary streambed in disturbed bamboo mixed with evergreen forest. The snake was very active and thrashed vigorously when restrained. ACKNOWLEDGMENTS This research was funded by a grant from the John D. and Catherine T. MacArthur Foundation to The Field Museum. Collecting and handling of the specimen in the field was in accordance with The Institutional Animal Care and Use Committee of the Field Museum (protocol no. FMNH 02 3). Jarujin Nabhitabhata facilitated fieldwork and Chatchay Chuechat and Sunchai Makchai assisted with fieldwork. Harold Voris, Alan Resetar, Jim McGuire, Jens Vindum, and Patrick David facilitated examining specimens. Sarah Drasner photographed the preserved specimen and Lisa Kanellos drew the illustrations. Sean O. Bober made the map. Sophie Molia and Peng Zhang provided French and Chinese translations, respectively. LITERATURE CITED ANANJEVA, N. B. AND B. L. STUART. 2001. The agamid lizard Ptyctolaemus phuwuanensis Manthey and Nabhitabhata, 1991 from Thailand and Laos represents a new genus. Russ. J. Herpetol. 8: 165 170. BOURRET, R. 1936. Les Serpents de L Indochine. Vols. I & II. Imprimerie Henri Basuyau & Cie., Toulouse. BROWN, W. C. AND A. E. LEVITON. 1961. Discovery of the snake genus Opisthotropis in the Philippine Islands, with description of a new species. Occ. Pap. Nat. Hist. Mus. Stanf. Univ. 8: 1 5. COX, M. J. 1991. The Snakes of Thailand and their Husbandry. Krieger Publishing Company, Malabar. COX, M. J., P. P. VAN DIJK, J. NABHITABHATA, AND K. THIRAKHUPT. 1998. Snakes and Other Reptiles of Thailand and South-East Asia. Asian Books, Bangkok. DAVID, P., M. J. COX, O. S. G. PAUWELS, L. CHANHOME, AND K. THIRAKHUPT. 2004. When a bookreview is not sufficient to say all: an indepth analysis of a recent book on the snakes of Thailand, with an updated checklist of the snakes of the Kingdom. Nat. Hist. J. Chulalongkorn Univ. 4: 47 80. DOWLING, H. G. 1951. A proposed standard system of counting ventrals in snakes. Brit. J. Herpetol. 1: 97 98. DOWLING, H. G. AND J. M. SAVAGE. 1960. A guide to the snake hemipenis: a survey of basic structure and systematic characteristics. Zoologica 45: 17 28+3 pls. GüNTHER, A. C. L. G. 1872. Seventh account of new species of snakes in the collection of the British Museum. Ann. Mag. Nat. Hist. 9: 13 37. MANTHEY, U. AND J. NABHITABHATA. 1991. Eine neue Agame, Ptyctolaemus phuwuanensis sp. n. (Sauria: Agamidae), aus Nordost-Thailand. Sauria 13(4): 3 6. ORLOV, N. L., I. S. DAREVSKY, AND R. W. MURPHY. 1998. A new species of mountain stream snake, genus Opisthotropis Gunther, 1872 (Serpentes: Colubridae: Natricinae), from the tropical rain forests of southern Vietnam. Russ. J. Herpetol. 5: 61 64. OKADA, Y. AND T. TAKARA. 1958. A new species of Liopeltis (Ophidia, Colubridae) from Ryukyu Islands. Bull. Bio. Geo. Jap. 20: 1 3. OTA, H. 2004. Field observations on a highly endangered snake, Opisthotropis kikuzatoi (Squamata: Colubridae), endemic to Kumejima Island, Japan. Cur. Herpetol. 23: 73 80. OTA, H. AND A. MORI. 1985. On the fourth specimen of Opisthotropis kikuzatoi. Snake 17: 160 162. POPE, C. H. 1935. The reptiles of China. Turtles, crocodilians, snakes, lizards. The American Museum of Natural History, Natural History of Central Asia 10: 1 604. RASMUSSEN, J. B. 1982. A new record of the rare Opisthotropis praemaxillaris (Serpentes: Colubridae). Amphibia-Reptilia 3: 279 280. SMITH, M. A. 1943. The Fauna of British India, Ceylon and Burma, including the Whole of the Indo-Chinese Sub-Region. Reptilia and Amphibia. Vol. III. Serpentes. Taylor and Francis, London.

40 Current Herpetol. 26(1) 2007 STUART, B. L. 2006. A second specimen of Parahelicops annamensis Bourret, 1934 (Serpentes: Colubridae: Natricinae). Hamadryad 30: 167 171. STUEBING, R. B. AND R. F. INGER. 1999. A Field Guide to the Snakes of Borneo. Natural History Publications (Borneo), Kota Kinabalu. TAYLOR, E. H. 1965. The serpents of Thailand and adjacent waters. Univ. Kansas Sci. Bull. 45: 609 1096. TAYLOR, E. H. AND R. E. ELBEL. 1958. Contribution to the herpetology of Thailand. Univ. Kansas Sci. Bull. 38: 1033 1189. TOYAMA, M. 1983. Taxonomic reassignment of the colubrid snake, Opheodrys kikuzatoi, from Kume-jima Island, Ryukyu Archipelago. Jpn. J. Herpetol. 10: 33 38. ZHAO, E.-M., Y.-M. JIANG, AND Q.-Y. HUANG. 1978. Three new snake species in China. Mater. Herpetol. Res. 4: 21. (in Chinese) ZHAo, E., M. HUANG, AND Y. ZONG (eds.). 1998. Fauna Sinica. Reptilia Vol. 3. Squamata. Serpentes. Science Press, Beijing. (in Chinese) APPENDIX Comparative Material Examined Institutional abbreviations used are CAS= California Academy of Sciences; FMNH=Field Museum of Natural History; MNHN=Muséum national d Histoire naturelle; MVZ=Museum of Vertebrate Zoology, University of California, Berkeley; SU=Stanford University. Opisthotropis alcalai: Philippines, Zamboanga del Norte Province, Mindanao Island, CAS (formerly SU) 22250 (holotype). Opisthotropis andersonii: China, Hong Kong, Hong Kong Island, MVZ 217690-91. Opisthotropis annamensis: Laos, Xe Kong Province, Kaleum District, Xe Sap National Biodiversity Conservation Area, FMNH 258637. Opisthotropis balteata: China, Hainan Province, Hainan Island, MVZ 23748. Opisthotropis boonsongi: Thailand, Loei Province, Dansai District, FMNH 135328 (holotype). Opisthotropis daovantieni: Vietnam, Gia Lai Province, Ankhe District, Buoenloy, FMNH 252009 (holotype), 252008 (paratype). Opisthotropis jacobi: Vietnam, Tonkin, MNHN 1933.10 (syntype), 1935.83, 1935.457, 1938.127. Vietnam, Vinh Phu Province, Vinh Yen District, Tam Dao, MVZ 224223, 226568. Opisthotropis kuatunensis: China, Fukien Province, Ch ungan Hsien, FMNH 24869-72 (paratypes). Opisthotropis latouchii: China, Jiangxi Province, Tai-Au-Hong, MVZ 23749. Opisthotropis maxwelli: China, Jiangxi Province, Hong-San, MVZ 23751. China, Fujian Province, Liung-Chon San, MVZ 23752. China, Guangdong Province, Yin Na Shan, MVZ 23753. Opisthotropis praemaxillaris: Laos, MNHN 1928.63, 1928.64 (syntypes). Opisthotropis typica: Malaysia, North Borneo, Kinabatangan District, FMNH 63596. Accepted: 20 April 2007