Diversity and distribution of Arctic Echinoderes species (Kinorhyncha: Cyclorhagida), with the description of one new species and a redescription of E. arlis Higgins, 1966

The kinorhynch fauna from Svalbard and the Arctic Ocean north of Svalbard was explored, and a total of nine species of Echinoderes was identified. Two species were new to science, and one, Echinoderes balerioni sp. nov., is described. Echinoderes balerioni sp. nov. is characterized by the presence of short middorsal spines on segments 4, 6, and 8, and in lateroventral positions on segments 6 to 9. Tubes are present in laterodorsal, sublateral, and ventrolateral positions on segment 2, lateroventral positions on segment 5, and lateral accessory positions on segment 8, and tergal extensions conspicuously long and spiniform. The collected material also offered the first chance to examine specimens of Echinoderes arlis with scanning electron microscopy, which prompted a redescription of the species. The recorded species are compared with all other known records of Echinoderes in the Arctic region, and the summarized data suggests that at least some species show a circumpolar distribution.