New record of three aquatic species of Enchytraeidae (Annelida: Clitellata) from Korea

Family enchytraeidae is one of the largest groups in clitellate annelids. It contains more than 700 species (Schmelz and Collado, 2015). Most of them dwell in ter­ restrial habitats, but some genera and species are aquat­ ic or amphibious in both habitats (Giani, 1976; Timm, 1994; Rota and Healy, 1999; Schmelz, 2003; Erséus, 2005). They play important roles in the soil and sediment ecology as environmental indicator species as they could be useful parameters for soil quality assessments (Did­ den, 1993; Graefe, 1993; Graefe and Schmelz, 1999). It is difficult to identify enchytraeid species due to strong morphological resemblance between closely related species in the location of chaetae and the shape of the reproductive organs, etc (Schmelz, 1996; Mastamoros, 2011). There have been many studies on this group of animal in Asia, and most of them focused on terrestrial specie. However, a few species aquatic or semi­aquat­ ic species have been reported (Yamaguchi, 1953; Torii and Ohtaka, 2007; Wang and Cui, 2007; Chen and Xie, 2008; Torii, 2012). According to recent studies about this group of animals in Korea, 27 terrestrial species and 2 aquatic species have been reported (An and Yang, 2009; Dózsa­Farkas and Hong, 2010; Christensen and Dózsa­Farkas, 2012; Dózsa­Farkas et al., 2014). Two aquatic species, however, were undetermined: Henlea sp. 1 and Mesenchytreanus sp. 1 (Park et al., 2013). Here, we report three aquatic enchytraeid species new to Korea: Fridericia glandifera Friend, 1913, Henlea montana Rota, 1994 and Marionina brendae Bretscher, 1899.