Revision of an Arctic kinorhynch species: Echinoderes svetlanae and E. tubilak are junior synonyms of E. remanei

The kinorhynch species Echinoderes remanei (Blake, 1930) is redescribed herein, based on the material housed in the National Museum of Natural History, Smithsonian Institution in Washington D.C as well as specimens collected at several other sites in the Northern Hemisphere. Echinoderes remanei is characterized by the presence of middorsal spines on segments 4 to 8 and lateroventral spines on segments 6 to 9; four pairs of glandular cell outlets type 2 on segment 2 (subdorsal, laterodorsal, sublateral, and ventrolateral), and one pair on segment 4 (subdorsal), 5 (midlateral), 8 (sublateral) and 10 (laterodorsal); lateroventral tubes on segment 5; and by sexual dimorphism expressed in lateral terminal spine lengths (in females, the lateral terminal spines are about half as long as those in males). The study also reveals that the two other species, Echinoderes tubilak Higgins & Kristensen, 1988 and Echinoderes svetlanae Adrianov, 1999 in Adrianov & Malakhov (1999) are conspecific with E. remanei. Therefore, E. tubilak and E. svetlanae are proposed as junior synonyms of E. remanei and are synonymized with E. remanei (Blake, 1930).