BioInvasions Records (2018) Volume 7, Issue 1: 15–19 Open Access DOI: https://doi.org/10.3391/bir.2018.7.1.03 © 2018 The Author(s). Journal compilation © 2018 REABIC Rapid Communication Correcting misidentifications and first confirmation of the globally-invasive Physa acuta Draparnaud, 1805 (Gastropoda: Physidae) in Thailand and Laos Ting Hui Ng1,*, Yanin Limpanont2, Yupa Chusongsang2, Phirapol Chusongsang2 and Somsak Panha1,* 1Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand 2Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand Author e-mails: [email protected] (THN), [email protected] (YL), [email protected] (YC), [email protected] (PC), [email protected] (SP) *Corresponding authors Received: 11 September 2017 / Accepted: 14 December 2017 / Published online: 27 January 2018 Handling editor: Kenneth Hayes Abstract Introduced freshwater gastropods in the Indo-Burmese region may be under-documented owing to a lack of research attention. For the first time, we report on the widespread establishment of the globally invasive freshwater snail Physa acuta (Physidae) in Thailand and Laos, including decades old records that had previously been misidentified as Camptoceras jiraponi (Planorbidae). Occurrence of Physa acuta as hitchhikers among ornamental aquatic plants suggests that the ornamental trade was a likely introduction pathway of the species into Thailand. That a globally invasive species was able to spread unnoticed for such a long period of time highlights the need for countries like Thailand to focus research efforts on prevention and early detection of introduced species, in addition to increasing our understanding of native biodiversity. Key words: freshwater snail, taxonomy, Camptoceras jiraponi, alien species, establishment, spread, Indo-Burma Introduction 2012; Ng 2016; Ng et al. 2014a, 2014b, 2015b, 2016a, 2016b), with half of those species being Almost 300 species of freshwater gastropods are found in the ornamental pet trade (Ng et al. 2016c). found in Thailand (Brandt 1974; Nabhitabhata 2009), Given that the ornamental pet trade is one of the but in the monograph that is still considered the probable sources of introduction of Pomacea spp. main authority on freshwater molluscs for Southeast into Thailand (Chanyapate and Archavakom 1999), Asia, Brandt (1974) only listed Amerianna carinata it would be unsurprising if other freshwater molluscs (H Adams, 1861) as being introduced. Four decades have been introduced via the same pathway, but later, the most notorious invasive freshwater snails have thus far remained undetected or misidentified. in Thailand are the South American Ampullariidae, One species that may have been introduced into Pomacea canaliculata (Lamarck, 1822) and Pomacea Malaysia and Singapore via the ornamental pet trade maculata Perry, 1810, which were the focus of is Physa acuta Drapranaud, 1805, but it was mis- intensive research in the 1990s because of the extensive identified as Physastra sumatrana (Martens, 1897) damage they caused to rice fields (Keawjam and for many years (see Ng et al. 2015b). Upatham 1990; Halwart 1994; Chanyapate and The globally invasive Physa acuta originates Archavakom 1999; Cowie et al. 2017). Other than from North America (Lydeard et al. 2016; Vinarski these species, only one freshwater snail, Gundlachia 2017). While there appears to be no published accounts sp. (Planorbidae), has reportedly been introduced of the species being established in Thailand to date, (Upatham et al. 1983). In contrast, Singapore, which Physa acuta has previously been collected from tanks is 700 times smaller than Thailand, has 25 species of within a research facility in the capital city of Bangkok non-native freshwater molluscs recorded (Tan et al. (Rico et al. 2014). In this article, we report for the first 15 T.H. Ng et al. time that Physa acuta has established and spread throughout Thailand, and correct previous erroneous identifications of this species as Camptoceras jiraponi Hubendick, 1967, from specimens collected from Thailand and Laos. Methods Specimens deposited at the Chulalongkorn University Museum of Natural History (CUMZ), Mollusk Museum of the Faculty of Tropical Medicine, Mahidol Uni- versity (TMMU), and the Department of Biology, Khon Kaen University (KKU) were examined (Supplemen- tary material Table S1). The specimens were collected by hand or using nets in various freshwater habitats throughout Thailand and Laos for biodiversity surveys, regular monitoring of intermediate hosts of zoonotic parasites, or macro-invertebrate surveys for assessment of fresh waters between 2005 and 2017. Specimens were also collected from a bag of ornamental aquatic plants purchased from a market in Bangkok, Thailand. Identification of species was based on comparison with original descriptions, photographs of type material of Physa acuta and Camptoceras jiraponi (Draparnaud 1805; Hubendick 1967; Brandt 1974; Ng et al. 2015b), and descriptions of topotypic speci- mens of Physa acuta (Paraense and Pointier 2003). Results All sixty individuals from 13 lots were examined and Figure 1. Confirmed occurrences of Physa acuta in Thailand and identified as Physa acuta (Table S1). Four of the Laos and the ornamental trade, indicated by numbered black lots—one from Phang Nga province in southern circles. Thailand: 1. Nong Khai province, 2. Phang-Nga province, 3. Chiang Mai province, 4. Phetchabun province, 5. Nakhon Thailand, and three from Khammouane and Vientiane Phanom province, 6. Suphanburi province, 7. Phitsanulok province in Laos—were originally identified as Camptoceras and 8. Nakhon Sawan province. Laos: 9. Vientiane province and jiraponi. The specimens were collected from eight 10. and 11. Khammouane province. 12. Ornamental pet shop in provinces in Thailand and two provinces in Laos, Bangkok, Thailand. and were found in natural (rivers), human-modified (paddy fields) and artificial (concrete pots or ponds and among ornamental aquatic plants) habitats (Figure range in North America, and may have been intro- 1). Specimens were also collected as hitchhikers on duced to Europe as early as the 1700s (Lydeard et al. aquatic plants being sold in an ornamental pet trade 2016; Vinarski 2017). The species and its congeners shop in a market in Bangkok. All material examined have been introduced to most of Southeast Asia: had sinistral, ovate shells with smooth surfaces Malaysia (Ali 1993; Hill et al. 1997; Ng et al. 2017), (Figure 2), and specimens that were collected in 2017 Indonesia (Mienis 2005), Myanmar (Win et al. 2011), were observed to have mottled bodies within translucent Vietnam (Bousset et al. 2013; Do 2015), Singapore shells when alive (Figure 2K). The examined shells (Ng et al. 2015b) and Brunei (Ng et al. 2015a). The ranged from 4–10 mm in height. original introduction of Physa acuta was probably much earlier, but based on examined material we can Discussion confirm that the species has been established in Thailand in a northeastern province since 2001, in For the first time, we confirm the establishment and northern and southern provinces since 2005, and in spread of the globally-invasive Physa acuta in Thailand Vientiane in Laos for almost thirty years. All these and Laos based on museum material. Physa acuta specimens were initially identified as Camptoceras has a long history of introduction outside its native jiraponi (Table S1). 16 Globally-invasive Physa acuta in Thailand and Laos Figure 2. Physa acuta from Thailand and Laos, and the ornamental trade. Thailand: A. Nong Khai province, B. Phang-Nga province, C. Chiang Mai province, D. Phetchabun province, E. Nakhon Phanom province, F. Suphanburi province, G. Phitsanulok province and H. Nakhon Sawan province. Laos: I. Vientiane province and J. Khammouane province. K. Hitchhiker among aquatic plants sold in an ornamental pet shop in Bangkok, Thailand. Scale bar = 1 mm. Photographs by Ting Hui Ng and Phirapol Chusongsang. Figure 3. A. Holotype of Camptoceras jiraponi (SMF 197364), B. Physa acuta from Nong Khai province, Thailand (TMMU 1479). Scale bar = 1 mm. Photographs by Sigrid Hof, courtesy of Ronald Janssen, Sektion Malakologie, Senckenberg Research Institute Frankfurt a. M., and Phirapol Chusongsang. Camptoceras jiraponi also has a sinistral shell but (Thailand), and Brandt (1974) recorded only one other differs from Physa acuta in that it has a more inflated locality in Thailand in the southern province of Nakhon body whorl, shorter spire, more impressed suture and Si Thammarat. Camptoceras jiraponi is assessed as periostracal hairs (Figure 3, also see Hubendick 1967: Least Concern by the IUCN, and is assumed to have p. 168; Brandt 1974: Plate 16, Figure 1). The type loca- a widespread distribution in Thailand (Simonis lity of Camptoceras jiraponi is Thonburi (Hubendick 2012). Based on available material from two 1967), within the wider Bangkok metropolitan area published studies, we identified specimens of Physa 17 T.H. Ng et al. acuta, which were previously recognised as Acknowledgements Camptoceras jiraponi (Sri-Aroon et al. 2006, 2015). We would like to thank Kenneth Hayes and two anonymous No specimens that could be identified as Campto- reviewers for their constructive comments that helped improve the ceras jiraponi were collected from the field, nor manuscript. We would also like to thank the members of the found in the collections that were examined.