ИСТИНА

Two new species associated with external and internal prokaryote symbionts from the Gollum Channel System and the edge of the Whittard Canyon area are described in this study: 1) Parastomonema sp. (Order Monhysterida, Family Sipholaimidae) and 2) Eubostrichus sp. (order Desmodorida, family Desmodoridae, subfamily Stilbonematinae). The Parastomonema specimens contain internal prokaryote symbionts within a degenerated gut, which are rather large and unusually transparent. The filiform Eubostrichus nematode specimens are covered on the outside with long and slender, slightly curved prokaryote cells which are attached to the cuticle. Both species were found in an unusual place; all hitherto known symbiotic species of Astomonema-Parastomonema are confined within intertidal or shallow (sublittoral) sites, mostly under reduced conditions (sulphide layer in sediments or methane seeps). So far, only once have Stilbonematinae species been found in the deep sea (900 m water depth, Darwin mounds, NE Atlantic).