In Korea, both Sympetrum depressiusculum Sélys, 1841 (Odonata: Libellulidae) and Sympetrum frequens Sélys, 1883 are recorded. However, the identity of Korean populations and the validity of listing the two species have not yet been settled. In this study, we collected 74 individuals from Kroea, Russia, the Netherlands, and Japan. These were sequenced for COI, 16S rRNA, and ITS region. Major morphological characters and phylogenetic, network, and structure analyses all consistently suggest that Korean populations form a single species. Consequently, it could be valid to treat Korean populations as one species, S. depressiusculum, by applying the senior name.

• Jee-Young Pyo(Department of Applied Biology, College of Agriculture & Life Sciences, Chonnam National University, Republic of Korea) Corresponding author
• Sung-Soo Kim(Institute for East Asian Environment and Biology, Seoul, Republic of Korea)
• Jeong Sun Park(Department of Applied Biology, College of Agriculture & Life Sciences, Chonnam National University, Republic of Korea)
• Jong-Moon Kim(Institute for East Asian Environment and Biology, Seoul, Republic of Korea)
• Yang-Keun Song(Institute for East Asian Environment and Biology, Seoul, Republic of Korea)
• Iksoo Kim(Department of Applied Biology, College of Agriculture & Life Sciences, Chonnam National University, Republic of Korea)