First South Korean Record of Beetle Suborder Myxophaga Extends Its Documented Range in Continental East Asia

Myxophaga is a minute beetle suborder that is easily overlooked because of its small body size and specialization on wet microhabitats. Here, we report Sphaerius from two riparian localities in South Korea, representing the first record of Myxophaga from the Korean Peninsula. This discovery also represents the northeasternmost known record of Myxophaga from continental East Asia, distinct from previous island records in Japan and Taiwan. Specimens were collected from saturated riparian substrates near the active waterline. Scanning electron microscopy confirmed characters consistent with Sphaerius, and the Korean COI barcode sequences were distinct from all other available Sphaerius sequences, although their position within the genus remained unresolved. Because records of East Asian Sphaerius remain taxonomically undetermined, we identify the Korean material as Sphaerius sp. This record expands the known continental distribution of Myxophaga in East Asia and highlights the value of targeted surveys in riparian microhabitats.