Four Unrecorded Species of Tubificid Oligochaetes (Annelida: Clitellata) in Korea

Tubificid oligochaetes are common and frequently dominant in freshwater benthic habitats. They are so tolerant to water pollution that they are often used as biological indicators. Faunistic studies of Korean freshwater oligochaetes have been actively conducted recently. The most well studied oligochaete family in Korea is the tubificids following the naidids. Nine species of tubificids have been reported so far. Nevertheless, many species of tubificids still remain to be discovered in Korea. In this study, we added four species of tubificid oligochaetes to the Korean fauna, including Linmodrilus profundicola (Verrill, 1871), Potamothrix heuscheri (Bretscher, 1900), Tubifex blanchardi $Vejdovsk\acute{y}$ , 1891, and Ilyodrilus templetoni (Southern, 1909) based on specimens collected from three locations in Korea: Cheonan-si, Geoje-si, and Seocheon-gun. In particular, P. heuscheri was first reported in Asia.