Korean J. Malacol. 26(4): 275-283, 2010 - 275 - Received Septemver 27, 2010; Revised October 21, 2010; Accepted November 1, 2010 Corresponding author: Kim, Woo-Jin and Jung, Hyungtaek Tel: +82 (51) 720-2451 e-mail: wjkim@nfrdi.go.kr, chunght77@gmail.com 1225-3480/24364 Systematic Relationships of Korean Freshwater Snails of Semisulcospira, Koreanomelania, and Koreoleptoxis (Cerithiodiea; Pleuroceridae) revealed byMitochondrial Cytochrome Oxidase I Sequences Woo-Jin Kim 1 , Dae-Hee Kim 4 , Jun Sang Lee 2 , In-Chul Bang 3 , Wan-Ok Lee 4 and Hyungtaek Jung 1 1 Biotechnology Research Division, National Fisheries Research and Development Institute, Busan 619-902, Korea 2 Institute of Environmental Research, Kangwon National University, Chunchon 200-701, Korea; 3 Department of Marine Biotechnology, Soonchunhyang University, Asan 336-745, Korea 4 Central Regional Inland Fisheries Research, National Fisheries Research and Development Institute, Cheongpyeong, Gyeonggi-do 477-815, korea ABSTRACT Many freshwater snail taxa are difficult to identify using morphological traits due to phenotypic plasticity. However, using of molecular DNA marker in combination with morphological traits can provide a reliable means for discriminating among freshwater snail taxa including cryptic species. To discriminate among Korean freshwater snail taxa and resolve their systematic relationships, wesequenced a fragment of mtDNA cytochrome oxidase I (COI) gene from 82 specimens collected from ten different sites distributed along the Korean peninsula. We identified more than seven freshwater snail taxa including cryptic species in Korea. Whereas traditional shell morphology of freshwater snails offers only weak discriminatory power for recognizing ‘good’ taxa, DNA sequence data provided positive and reliable identification. In addition, a major Semisulcospira clade was clearly separated from the remaining lineages observed including cryptic species. However, a phylogenetic tree inferred from the COI gene data did not fully resolve systematic relationships among pleurocerid taxa in Korea. Establishing more robust shell characteristics for identifying taxa unambiguously and hence improving traditional key shell morphology characters for freshwater snail species is an urgent requirement and will require more rigorous examination of all nominal taxa. While molecular data generated here will be useful for species identification and for describing the systematic relationships among Korean freshwater snails, further analysis will be required. Key words: freshwater snail, Semisulcospira, Koreanomelania, Koreoleptoxis, mitochondrial cytochrome oxidase I, systematic relationships INTRODUCTION Freshwater snails in the genera Semisulcospira, Koreanomelania, and Koreoleptoxis are widely distributed across East Asia (Davis, 1969). While snails have long been used for human consumption, over-exploitation, habitat degradation, and water pollution by insecticides and heavy metals have resulted in population declines and loss of species richness and diversity. Restoration efforts based on cytological and reproductive studies have been conducted (Kim et al., 1987; Chang et al., 2000) to address declining snail populations. However, accurate species identification remains problematic and can compromise restoration programs. As an initial step, understanding species delimitation is an important component in developing successful and sustainable