Biodiversity Journal, 2014, 5 (2): 371–373 Rediscovery of the critically endangered cyprinid fish Epalze- orhynchos bicolor (Smith, 1931) from West Thailand (Cyprini- formes Cyprinidae) Sitthi Kulabtong 1,2* , Siriwan Suksri 3 , Chirachai Nonpayom 4 & Yananan Soonthornkit 2 ABSTRACT KEY WORDS Received 01.04.2014; accepted 18.05.2014; printed 30.06.2014 In the present paper, we report on the critically endangered cyprinid fish, Epalzeorhynchos bicolor (Smith, 1931) “rediscovered” in Maeklong Basin, West Thailand. Moreover, distribu- tion data and biological observations of this species are also provided. Epalzeorhynchos bicolor; Cyprinidae; Maeklong Basin; Thailand. INTRODUCTION The freshwater cyprinid fish genus Epalze- orhynchos Bleeker, 1855, order Cypriniformes Bleeker, 1859 and family Cyprinidae Cuvier, 1817, has been reported for Southeast Asia only (Kottelat & Whitten, 1996; Doi, 1997; Monkolprasit et al., 1997; Yang & Winterbottom, 1998). According to the current taxonomic status of this genus, it comprises 4 valid species: E. frenatum (Fowler, 1937) from Chao Phraya Basin, Maeklong Basin in Thailand and Mekong Basin in Indochina; E. kalopterum (Bleeker, 1850) from South Thai- land to Indonesia; E. munense (Smith, 1934) from Mekong Basin in Indochina; E. bicolor (Smith, 1931) from Central and West Thailand (Smith, 1931; Vidthayanon et al. 1997; Kottelat, 2013). RESULTS The cyprinid fish Epalzeorhynchos bicolor (Fig. 1) is an endemic fish of Thailand. The distri- bution of this species is reported only for Lower Chao Phraya Basin, Bangpakong Basin and Lower Maeklong Basin (Smith, 1931; Vidthayanon et al., 1997; Vidthayanon, 2005, 2011). It has been threatened by mass collecting for aquarium trade, pollution of many sources and habitats destruction (Vidthayanon, 2011) and, according to the IUCN Red List of Threatened Species (Vidthayanon, 2005, 2011), this fish is a threatened species. In 1996, it was even thought to be extinct in the wild since there was no documented evidence of it the last more than 50 years (Kottelat & Whitten, 1996). Currently, the status of the species is poorly known. In 2011, Dr. Chavalit Vidthayanon assessed that the species is still extant in the Chao Phraya 1 Save wild life volunteer Thailand, Wangnoi District, Ayuttaya Province 13170, Thailand 2 Fisheries Program, Faculty of Agro-Industrial Technology, Rajamangala University of Technology Tawan-ok Chantaburi Campus, Chantaburi, Thailand 3 Reference Collection Room, Inland Fisheries Resources Research and Development Institute, Department of Fisheries, Thailand 4 534/26 Soi Phaholyothin 58, Phaholyothin Rd. Sai Mai, Bangkok, Thailand * Corresponding author, email: kulabtong2011@hotmail.com