The 4 th Science Research Conference. 12-13 March 2012. Faculty of Science, Naresuan University. Morphological Variation of Truncate-Snouted Burrowing Frog (Glyphoglossus molossus) of Thailand Chalida Laojumpon 1 Suravech Suteethorn 2 and Komsorn Lauprasert 2,* 1 Department of Biology, Faculty of Science, Mahasarakham, Khantarawichai, Mahasarakham 44150 2 Palaeontological Research and Education Centre, Mahasarakham University, Khamrieng, Mahasarakham, 44150 Thailand ABTRACT Two hundred and ninety seven specimens of Glyphoglossus molossus from Northern, Central and Northeastern Thailand were examined for morphological variation using univariate and multivariate statistics with traditional morphometrics. There were no significant differences between the sexes but variations in shape and size between regions were found. The pattern of variations in this study indicates that morphometric variation in Glyphoglossus molossus probably results from geographic barriers correlated with climate factors. Keywords: Morphological variation, Truncate-Snouted Burrowing Frog, Glyphoglossus molossus, Thailand. 1. INTRODUCTION Understanding the physical structure of an organism is a prerequisite to understanding its phylogenetic relationships, behavior, and relationship with the environment (Duellman and Trueb, 1994). Thus, qualitative and quantitative analyses of the relationships between morphological variations and ecological factors have become increasingly widespread in the last decade (Claude et al., 2004). Although morphological study has been a basic tool in biology for many centuries, it has many limitations because the results are mainly qualitative data from descriptive methods which can sometimes not be clear and difficult to understand (Richtsmeier et al., 2002, Adams et al., 2004). Because of this problem, morphologists try to develop numerous methods to study the morphological characters of organisms such as morphometric methods. Several researches indicate that amphibians show a high level of morphological variation especially in the cranium (Duellman and Trueb, 1994; Meijden et al., 2007 and Amor et al., 2009). Thus, they are a very good model for studying the effects of environment on morphological variation. In Thailand, 137 species of amphibians were reported by The Royal Forest Department (Nabhitabhata and Chan-ard, 2005). Unfortunately, the status, of many species, has been classified as at risk under the IUCN Red List of Threatened Species (IUCN, 2011) because of the influence of climate changes and habitat fragmentation as well as a lack of knowledge about ecological, behavioral, and taxonomic data (Bickford, 2010). This problem also includes Glyphoglossus molossus, a native amphibian of Cambodia, Lao People's Democratic Republic, Myanmar, Thailand, and Vietnam (Nabhitabhata and Chan-ard, 2005). Recently, this animal was close to being classified as a threatened species under IUCN because of the affects of forest degradation and over harvesting for food during the breeding seasons by local people (Dijk and Chan-ard, 2010). However, biological reports of this species are still rare. Additionally, there is no other published study focusing on morphological variation. Thus the aim of this study was to investigate morphological variation in terms of sexual dimorphism and geographic variation, with the implementation of multivariate statistics. Figure 1. Map of sampling localities which presents geographic regions of Thailand (modified from Khedari, 2002). (Names of localities shown in Table1). 2. STUDY AREAS Environment is a factor that strongly influences the shape and size of amphibians. (Ashton, 2002; Laugen et al., 2005; Adams et al., 2008 and Kingsolver and Huey, 2008). The study area was accordingly divided according to the temperature, relative humidity and geographic structure (Khedari et al., 2002). * Corresponding author