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Home , Enhydris, Homalopsidae, Khon Kaen Province, Surin Province

Herpetology Notes, volume 12: 561-564 (2019) (published online on 31 May 2019)

Enhydris subtaeniata (Bourret 1934) (Serpentes: ): New distribution record and map

Yodchaiy Chuaynkern1,*, Prateep Duengkae2, Chantip Chuaynkern1, Krit Pinthong3 and Alonglod Tanomthong1

The mud subtaeniata was molecular analysis, and the specimen was fixed in described as Hypsirhina enhydris subtaeniata by 10% formaldehyde, and subsequently transferred to Bourret (1934) based on specimens from Kompong 70% alcohol. The specimen is housed in the Khon Speu, (Lectotype: MNHN 1958.04.74; Kaen Vertebrate Collection (KKUC 01153), Khon designated by Murphy, 2007). This snake is distributed Kaen University, Province, northeastern in lowland regions of central Indochina, namely in . the Middle and Lower Mekong River basins of , The specimen was allocated to Enhydris subtaeniata Thailand, Vietnam and Cambodia (Voris et al., 2012). for showing morphological characteristics considered The known distributional records indicate that there is a huge distribution gap in the southern part of northeastern Thailand. This gap lies between four known localities (Fig. 1), i.e., Ubonrat Dam () in the northwest, Ban Badan (Nakhon Ratchasima Province) in the southwest, Tonle Sap (Cambodia) in the south, and Dong Khanthung (Lao PDR) in the southeast. In the huge area between these localities, records of Enhydris subtaeniata are lacking. We herein report on an additional record that fills this distribution gap. We captured an adult female (Figs. 2, 3) on 7 March 2015 by using a gill net in a 13-year-old private pond (15.054611, 103.691962) which is connected to the public reservoir in Baan Aayong (=Aayong village), Taen Subdistrict, , (Fig. 1). The snake was euthanized by injecting a nebutal overdose. Pieces of its liver were cut for further

1 Department of Biology, Faculty of Science, , Mueang Khon Kaen, Khon Kaen, 40002 Thailand. 2 Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart Figure 1. Collection localities of Enhydris subtaeniata: 1) University, 10900, Thailand. Bung Boraphet, , Thailand. 2) Ban 3 Department of Fundamental Science, Faculty of Science Badan, Nakhon Ratchasima Province, Thailand. 3) Ubonrat and Technology, Surindra Rajabhat University, Chatuchuk, Dam, Khon Kaen Province, Thailand. 4) Sikhoraphum Bangkok, 10900 Thailand. District, Surin Province, Thailand. 5) Dong Khanthung, Laos. * Corresponding author. E-mail: [email protected] 6) Tonle Sap, Cambodia. 7) U. Minh Thong, Vietnam. 562 Yodchaiy Chuaynkern et al.

provincial areas, only the records from Khon Kaen, Nakhon Ratchasima, and Nakhon Sawan were based on voucher specimens. Some works reported distribution of Enhydris subtaeniata in Prachin Buri Province but did not refer to voucher specimens (see Nabhitabhata and Chan-ard, 2005; Chuaynkern and Chuaynkern, 2012; Cox et al., 2012). Voris et al. (2012) collected intensively in Prachin Buri (Kabin Buri District) but failed to record the . Thus the occurrence of Enhydris subtaeniata in this province requires confirmation. Cox et al. (2012) included (northeastern Thailand) and Songkhla () provinces in the distribution range of Enhydris subtaeniata, but it is likewise unclear if the records are based on voucher specimens. Figure 2. Enhydris subtaeniata (KKUC 01153; SVL 537 Most of our formal knowledge of the Thai homolopsid mm, TaiL 92.1 mm) from Baan Aayong, Taen Subdistrict, Srikhoraphum District, Surin Province, Thailand in life. comes from the research of Cox (1991), Murphy (2007), Cox et al. (2012) and Chan-ard et al. (2015). Intensive surveys for obtaining additional localities and specimens are required. This is especially the case in diagnostic for the species (Cox, 1991; Murphy, 2007; northeastern Thailand. Previous works were mainly Cox et al., 2012; Voris et al., 2012; Murphy and Voris, 2014). Its morphological characteristics are as follow: snout-vent length (SVL) 537 mm; tail length (TaiL) 92.1 mm; dorsal scale rows (after Dowling, 1951) 21: 21: 19, at neck, mid-body and anal respectively; ventral scales 143; subcaudal scales 46; nasals in contact; loreal 1; preocular 1; postoculars 2; temporals 1+2; supralabials 8; infralabials 10 (Fig. 3). The morphological characteristics of the newly collected specimen is presented alongside a summary of characteristics of Enhydris species from Surin Province of Thailand in Table 1. To date, Enhydris subtaeniata has been observed in four countries, Cambodia, Lao PDR, Thailand and Vietnam (Murphy, 2010; Lukoschek et al., 2011; Voris et al., 2012; Uetz et al., 2014). In Cambodia, two specimens were collected from Tonle Sap, Siem Reap Province (Karns et al., 2010; Lukoschek et al., 2011; Voris et al., 2012). In Lao PDR, a series of Enhydris subtaeniata was collected from Dong Khanthung, Champasak Province which lies above the Khone Falls on the southern edge of the Middle Mekong (Lukoschek et al., 2011). The record from Vietnam is based on specimens collected from U. Minh Thong Nature Reserve (Lukoschek et al., 2011). In Thailand, the species was recorded from six provincial areas including Khon Kaen, Nakhon Figure 3. Dorsal (A), ventral (B), and lateral (C) views of Ratchasima, Nakhon Sawan, Prachin Buri, Udon Thani, the head of Enhydris subtaeniata (KKUC 01153) from Baan and Songkhla (Karns et al., 2005; Murphy, 2007; Cox Aayong, Taen Subdistrict, Srikhoraphum District, Surin et al., 2012; Voris et al., 2012). Among these Thai Province, Thailand. Photographs not to scale. Enhydris subtaeniata: New distribution record and map 563 .

1 1 6 6 9 9 1 1 Enhydris subtaeniata Enhydris - - - - 43 2 2.1 4 2 1 2 1 9 equal spots, 4-6 scales TH (Surin) KKUC 01153

1 na 21 na 2,5 This study or 3 or3 VN spots, 46-69 2 134-153 4-6 scales zig-zag stripezig-zag stripe zig-zag

468-557

436-688 537 1 1 2 21 KH KH, TH,LA, blotches, 4-5 scales some spotssome

na na na na H H 1 2 1,3 T 21-23 blotches, 4-5 scales

95-180 100-161 340-650 1 2 21 na na na 1,5 VN 19-21 19-20 19-21 19-21 flared flared flared flared flared 42-49 50-54 53-76 23-25 23-25 23-26 23-24 49-56 53-68 64-73 first 3first 3 first 3 first 3 first 3 first smooth smooth smooth smooth smooth uniform uniform uniform uniform uniform 108-117 111-116 117-127 117-120 124-133 124-135 blotched blotched blotched stripe stripe up up to 390 340-530 4-5 scales and of the newly collected specimen from Surin Province of Thailand assigned to assigned Thailand of Province Surin from specimen collected newly of the and

a a Enhydris 2 n n 1,4 1-23 1-23 9-21 tripe triated stripe s 2 54-693 50-788 1 57-76 21-27 64-83 first 3first longate s 3 3 153-174 153-170 e (3 rarely) 2 stripe or uniform blotches, SG SG (?),TH, LK, VN LA, MY,LA, MM, NP, PK,

H H CN, ID, BD, KH, IN, 1 2 na na na na 8-49 8-49 0-23 0-23 4-60 4-60 T tripe pots, irst irst 3 s s 10-121 16-122 4 3 2 f 1 1 2-3 scales E. E. chanardi E. enhydris E. innominata E. jagorii E. longicauda subtaeniata E. subtaeniata E. Sources of information Dorsal onscale rows mid-body 21 Subcaudals in males Characteristics Dorsal post-body scale rows 19-21 Longest pairLongest of chin shields Pattern on scale rows 5-7 Labials touchingLabials loreal Pattern on scale rows 1-3 SVL in SVL (mm)males in SVL females (mm) inVentrals males Ventrals inVentrals females Subcaudals in females Shape of anterior shields chin flared Number Number of pairs of chin shields 2 TaiL females in (mm) Distribution Dorsal onscale rows neck Dorsal scale ornamentation smooth Pattern on edges of ventrals stripe zig-zag solid or serrated uniform uniform uniform, TaiL in (mm)males Mid-ventral pattern posterior uniform Table 1. Morphological characteristics of the currently recognized species of species recognized currently of the characteristics Morphological Information sources: 1=Murphy and Voris (2005), 2=Cox et al. (2012), 3=Pongcharoen et al. (2015), 4=Karns et al. (2010), 5=Murphy (2007). Countries abbreviation: CN=China, ID=Indonesia, ID=Indonesia, CN=China, abbreviation: Countries (2007). 5=Murphy (2010), al. et 4=Karns (2015), al. et 3=Pongcharoen (2012), al. et 2=Cox (2005), Voris and 1=Murphy VN=Vietnam. sources: Information TH=Thailand, Lanka, LK=Sri (?), SG=Singapore PK=Pakistan, NP=Nepal, MM=Myanmar, MY=Malaysia, PDR, LA=Lao IN=India, KH=Cambodia, BD=Bangladesh, Table 1. Table 564 Yodchaiy Chuaynkern et al. focused on the protected areas such as national parks or snake (Enhydris subtaeniata): the biogeographic importance wildlife sanctuaries (e.g., Stuart and Chuaynkern, 2007; of dynamic river drainages and fluctuating sea levels for Chuaynkern et al., 2015). However, the members of the semiaquatic taxa in Indochina. Ecology and Evolution 1(3): 330–342. mud snakes (Homalopsidae) mainly inhabit wetland Murphy, J.C. (2007): Homalopsid Snakes: Evolution in the Mud. reservoirs which are distributed in agricultural areas. Krieger Publishing, Malabar. 249 pp. The Mekong mud snake Enhydris subtaeniata was Murphy, J.C. (2010): Enhydris subtaeniata. The IUCN Red List of never reported from protected areas of northeastern Threatened Species 2010: e.T176693A7284968. http://dx.doi. Thailand. Although several works paid attention to the org/10.2305/IUCN.UK.2010-4.RLTS.T176693A7284968. en. wetland and agricultural areas of northeastern Thailand Accessed on 11 December 2016. (Karns et al., 2005; Voris et al., 2012), the knowledge Murphy, J.C., Voris, H.K. (2005): A new Thai Enhydris (Serpentes: : Homalopsinae). The Raffles Bulletin of Zoology is probably still incomplete. Therefore, undiscovered 53(1): 143–147. populations of the mud snakes may exist in northeastern Murphy, J.C., Voris, H.K. (2014): A checklist and key to the Thailand and are waiting for intensive surveys to be homalopsid snakes (Reptilia, , Serpentes), with the discovered. description of new genera. Fieldiana: Life and Earth Sciences 8: 1–43. Acknowledgements. The authors would like thank our Nabhitabhata, J., Chan–ard, T. (2005) Thailand Red Data: Mammals, institutions for facilitating this work: Khon Kaen University and Amphibians. Office of Natural Resources and (Khon Kaen Province, northeastern Thailand) and Kasetsart Environmental Policy and Planning, Bangkok. 58 pp. University (Bangkok, ). Our special thanks Pongcharoen, C., Voris, H.K., Pattanavibool, A., Thirakhupt, K. go to Nithina Kaewtongkum and Pechrkawin Nurngsomsri (2015): Morphology and sexual dimorphism of the Jagor’s from the Department of Biology, Faculty of Science (Khon water snake, Enhydris jagorii at Bung Ka Loh wetland, Kaen University) for assistance in drawing and preparing the , Thailand. Journal of Wildlife in Thailand illustrations. We also thank Robert H. Orr for reviewing and 22(1): 47–59. correcting an earlier manuscript. Stuart, B. L., Chuaynkern, Y. (2007): A new Opisthotropis (Serpentes: Colubridae: Natricinae) from Northeastern Thailand. Current 26(1): 35–40. Reference Uetz, P., Hošek, J. (Eds.) (2014): The database, http://www. Bourret, R. (1934): Notes herpétologiques sur l’Indochine Française reptile-database.org/. Accessed on 17 February 2014. I. Ophidiens de Chapa. Bulletin general de l’Instruction Publique Voris, H.K., Murphy, J.C., Karns, D.R., Kremer, E., O’Connell, 7: 129–138. K. (2012): Differences among populations of the Mekong Mud Chan–ard, T., Parr, J.W.K., Nabhitabhata, J. (2015): A Field Guide Snake (Enhydris subtaeniata: Serpentes: Homalopsidae) in to the Reptiles of Thailand. Oxford University Press, Oxford. Indochina. Tropical Natural History 12(2): 175–188. 314 pp. Chuaynkern, Y., Chuaynkern, C. (2012): Checklist of reptiles in Thailand. Journal of Wildlife in Thailand 19(1): 75–162. Chuaynkern, Y., Duengkae, P., Chuaynkern, C., Chitchamnong, W. (2015): Isopachys borealis Lang & Böhme, 1990 (Squamata: Scincidae): new distribution record and map. Check List 11(1): 1–3. Cox, M.J. (1991): The Snakes of Thailand and Their Husbandry. Krieger Cundall Publishing, Malabar. 144 pp. Cox, M.J., Hoover, M.F., Thirakhupt, K., Chanhome, L. (2012): The Snakes of Thailand. Sirabutr Printing Co., Ltd., Bangkok. 845 pp. Dowling, H.G. (1951): A proposed standard system of counting ventrals in snakes. British Journal of Herpetology 1(5): 97–99. 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