Echinoderes beringiensis sp. nov. - The first Kinorhyncha from deep-sea methane seepages in the north Pacific

Abstract

A new species of echinoderid kinorhynch, Echinoderes beringiensis sp. nov., collected from bacterial mats at the deep-sea cold methane seepages area on the Chukchi slope (Bering Sea, NW Pacific), is described using light and scanning electron microscopy. This new representative of the most diverse kinorhynch genus is characterized by its unique arrangement of spines, tubes and glandular cell outlets and cuticular plates composition on trunk segment 11, thus being distinguished from other congeners. Modified glandular cell outlets type 2 are present in subdorsal, laterodorsal, sublateral and ventrolateral positions on trunk segment 2; in midlateral position on trunk segment 5; in sublateral position on trunk segment 8 in males, and in midlateral and sublateral position in female. Acicular spines are present in middorsal position on trunk segments 4–8, and in lateroventral position on trunk segments 6–9. Tubes are present in lateral accessory position on trunk segment 5. Trunk segment 11 has two tergal and two sternal cuticular plates. Echinoderes beringiensis sp. nov. constitutes the first kinorhynch species described from extreme, deep-sea environments of cold methane seepages in the Pacific Ocean, and the second representative of the Kinorhyncha known from the Bering Sea.