Journal of Threatened Taxa | www.threatenedtaxa.org | 26 September 2018 | 10(10): 12425–12428

Additional field records provide further resolution of the distribution of the Water Monitor Varanus salvator (Squamata: Varanidae) in northwestern Myanmar

Steven G. Platt ¹, Myo Min Win ² & Thomas R. Rainwater ³

^1,2 Wildlife Conservation Society - Myanmar Program, No. 12, Nanrattaw St., Kamayut Township, Yangon, Myanmar

³ Tom Yawkey Wildlife Center & Belle W. Baruch Institute of Coastal Ecology and Forest Science, Clemson University, P.O. Box 596, Georgetown, South Carolina 29442, USA

¹ sgplatt@gmail.com, ² 4nge86@gmail.com, ³ trrainwater@gmail.com (corresponding author)

doi: https://doi.org/10.11609/jott.4425.10.10.12425-12428 | ZooBank: urn:lsid:zoobank.org:pub:8AED5B33-C658-4538-89DF-165BCA7D3A77

Editor: Anonymity requested. Date of publication: 26 September 2018 (online & print)

Manuscript details: Ms # 4425 | Received 23 July 2018 | Final received 11 September 2018 | Finally accepted 15 September 2018

Citation: Platt, S.G., M.M. Win & T.R. Rainwater (2018). Additional field records provide further resolution of the distribution of the Water Monitor Varanus salvator (Squamata: Varanidae) in northwestern Myanmar. Journal of Threatened Taxa 10(10): 12425–12428; https://doi.org/10.11609/jott.4425.10.10.12425-12428

Copyright: © Platt et al. 2018. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

Funding: Andy Sabin; The Andrew Sabin Family Foundation;

The Critical Ecosystems Partnership Fund.

Competing interests: The authors declare no competing interests.

Acknowledgements: We thank the Minister of the Ministry of Environmental Conservation and Forestry, Director General and Deputy Director General of the Planning and Statistics Department of the Ministry of Environmental Conservation and Forestry, Director General and Deputy Director General of the Forest Department and the Director of NWDC for their dedication to wildlife conservation in Myanmar and allowing us to conduct fieldwork in northern Myanmar. We are grateful for the field assistance provided by Tun Win Zaw, Naing Win Aung, and Zaw Naing Oo. Support was provided by Andy Sabin and the Andrew Sabin Family Foundation, and the Critical Ecosystems Partnership Fund. TRR was supported by the Yawkey Foundation and Clemson University. We are indebted to Than Myint for securing the necessary permits and permission to conduct fieldwork. Finally, we are grateful to Lewis Medlock for advice on camera trapping, Flora Ihlow and Levinson Deb for assistance with obtaining literature, and Kyaw Zay Yar for preparing our map. This paper represents technical contribution number 6655 of the Clemson University Experiment Station.

Despite being one of the most common and widely distributed varanids in South and Southeast Asia (Bennett et al. 2010; Das 2010; Chan-ard et al. 2015), the distribution of the Water Monitor Varanus salvator (Laurenti, 1768) within Myanmar remains poorly delineated, particularly for the central and northern regions of the country (Cota et al. 2009; Sai Sein Lin Oo & Bates 2016). Smith (1935) stated that V. salvator was “plentiful throughout Burma” [now Myanmar] without mentioning any specific localities. Anderson (1878) and Boulenger (1888) reported specimens of V. salvator from the Bhamo and the Kachin Hills, respectively. Cota et al. (2009) suggested these earlier records could be in error, perhaps representing specimens obtained in markets or transported as food, and further noted that extensive collecting by research teams from the California Academy of Sciences failed to record V. salvator anywhere in central and northern Myanmar. More recently, Oo & Bates (2016) confirmed the occurrence of V. salvator in north-central Myanmar after photographing a large adult in Bhamo and finding a locally-collected specimen being offered for sale at a market in Banmauk, about 140km west of Bhamo (Fig. 1). Sai Sein Lin Oo & Bates (2016) concluded these records either (1) represent an isolated and perhaps relict occurrence or (2) the distribution of V. salvator extends up the Ayeyarwady River and its tributaries.

We herein present two additional photo records, which further document the distribution of V. salvator within northwestern Myanmar (Fig. 1). The first record was obtained on 26 April 2016 when one of us (MMW) photographed a juvenile (total length [TL] ca. 90–100 cm) V. salvator while traveling by boat along Nam Pi Lin Stream (25.683⁰N & 95.636⁰E; elevation ca. 100m) in Sagaing Region (Image 1). The monitor was basking on a log extending from a steep bank and over-hanging the stream, and dropped into the water as the boat approached. Nam Pi Lin Stream is encompassed within the boundaries of Htamanthi Wildlife Sanctuary. The habitat along this section of the stream is dense riparian forest and bamboo thickets transitioning into old-growth evergreen forest with increasing elevation away from the water. Additional information on the vegetation and physiography of Htamanthi Wildlife Sanctuary is provided by Beffasti & Galanti (2011).

The second photo record was obtained when a large adult V. salvator (TL ca. 150cm) was “captured” on a game camera deployed about 0.25km south-east of Limpha Village (25.808⁰N & 95.536⁰E; elevation ca. 132m) in Sagaing Region. The game camera (Moultrie Series A) was set in a densely vegetated seasonal swamp along the Chindwin River beside the carcass of a young domestic Water Buffalo Bubalus bubalis (Linnaeus, 1758) that had perished after becoming mired in deep mud. The motion-sensitive game camera (programed to take three photographs at 1-min intervals) was deployed from 17 February to 6 March 2018 (17 trap-nights) and captured a sequence of six images (1324-1326 hr) of a Water Monitor on 1 March (Images 2A–F). The first image shows the monitor with head and neck extended back and upwards in a near-vertical position usually exhibited when swallowing (Image 2A). The monitor then investigates the remains of the carcass (Image 2B–C) and moves across and away from the camera (Image 2D–F). At the time these photographs were taken the buffalo carcass consisted of little more than bones in a pool of fetid muck (Stage 6 of Payne 1965).

Our photo records from Nam Pi Lin Stream and Limpha Village extend the known distribution of V. salvator in Myanmar approximately 170km north and westwards of the recent records from Bhamo and Banmauk (Oo & Bates 2016). Collectively, these records strongly suggest the distribution of V. salvator extends up the Ayeyarwady and Chindwin Rivers into northern and northwestern Myanmar. We see no reason to assume these records represent an isolated relict occurrence of V. salvator in northern Myanmar as suggested by Sai Sein Lin Oo & Bates (2016). Given the lack of apparent geographic barriers to dispersal, we further suggest the distribution of V. salvator extends at least as far north as the Hukaung Valley in Kachin State. Obviously additional investigation will be required to resolve these biogeographical questions.

Our photo records of V. salvator appear to be assignable to the subspecies V. salvator macromaculatus Deraniyagala 1944, which until recently was thought to be restricted to Thailand (Koch et al. 2007; Cota et al. 2009; Sai Sein Lin Oo & Bates 2016). Although considerable inter-population variation is evident in V. salvator macromaculatus (Cota et al. 2009), the two individuals in our photo records exhibit attributes consistent with this subspecies, namely, 1) brownish dorsal background color with at least five transverse rows of ocelli and light dotting between rows, 2) light chin with prominent crossbands on snout, 3) light ventral surface with six dark, sharply pointed bars on lateral surface, and 4) anterior tail with transverse rows of light spots and ocelli, and posterior tail with distinctive alternating light and dark crossbands (Koch et al. 2007). Similarly, Sai Sein Lin Oo & Bates (2016) concluded the two specimens they examined in northern Myanmar were assignable to V. salvator macromaculatus. Finally, our experience highlights the potential for using automated game cameras for documenting the occurrence and behaviors of varanids (see also Ariefiandy et al. 2013; Bennett & Clements 2014).

References

Anderson, J. (1878). Anatomical and zoological researches: comprising an account of the zoological results of the two expeditions to western Yunnan in 1868 and 1875; and a monograph of the two cetacean genera, Platanista and Orcella. Bernard Quaritch, London, 985pp.

Ariefiandy, A., D. Purwandana, A. Seno, C. Ciofi, & T.S. Jessup (2013). Can camera traps monitor Komodo dragons, a large ectothermic predator? PLoS One 8(3): e58800; https://doi.org/10.1371/journal.pone.0058800

Beffasti, L. & V. Galanti (2011). Myanmar Protected Areas: Context, Current Status, and Challenges. Instituto Oikos, Ancora Libri, Milan, 86pp.

Bennett, D. & T. Clements (2014). The use of passive infrared camera trapping systems in the study of frugivorous monitor lizards. Biawak 8(1): 19–30.

Bennett, D., M. Gaulke, E.R. Pianka, R. Somaweera & S.S. Sweet (2010). Varanus salvator. The IUCN Red List of Threatened Species 2010: e.T178214A7499172; https://doi.org/10.2305/IUCN.UK.2010-4.RLTS.T178214A7499172.en

Boulenger, G.A. (1888). An account of the Reptilia obtained in Burma north of Tenasserim by M.L. Fea, of the Genoa Civic Museum. Annali del Museo Civico de Genovaa 2: 594–604.

Chanard, T., J.W.K. Parr, & J. Nabhitabhata (2015). A Field Guide to the Reptiles of Thailand. Oxford University Press, Oxford, 314pp.

Cota, M., T. Chan-Ard, & S. Makchai (2009). Geographical and regional variation of Varanus salvator macromaculatus in Thailand. Biawak 3(4): 134–143.

Das, I. (2010). A Field-guide to the Reptiles of South-east Asia. Bloomsbury, London, 376pp.

Koch, A., M. Auliya, A. Schmitz, U. Kuch, & W. Böhme (2007). Morphological studies on the systematics of South East Asian Water Monitors (Varanus salvator Complex): Nominotypic populations and taxonomic overview. Mertensiella 16: 109–180.

Payne, J.A. (1965). A carrion study of the baby pig Sus scrofa Linnaeus. Ecology 46: 592–602.

Sai Sein Lin Oo & P.J.J. Bates (2016). The rediscovery of the Common Water Monitor Lizard Varanus salvator (Squamata: Varanidae) in northern Myanmar. Journal of Threatened Taxa 8(5): 8827–6628; https://doi.org/10.11609/jott.2746.8.5.8827-8828

Smith, M.A. (1935). The Fauna of British India, including Ceylon and Burma. Reptilia and Amphibia. Vol. II.—Sauria. Taylor & Francis, London, 440pp.