Sea-bed photographs (benthos) from the Weddell Sea along two ROV profiles during Polarstern cruise ANT-XIII/3

Young specimens of cf. Pagothenia borchgrevinki were observed for the first time to cling to the subsurface of the marginal ice shelf in Drescher Inlet, southeastern Weddell Sea. Along an approximately 40-m-long videotransect at 80 m water depth, the abundance was roughly estimated to be 7 individuals per 10 m**2. This behaviour is interpreted to represent the most advanced adaptation to ice as a microhabitat for Antarctic fish.

A new genus Abyssogena from deep-water vents and seeps

A new genus Abyssogena is established for A. phaseoliformis (Métivier, Okutani & Ohta, 1986) and A. kaikoi (Okutani & Métivier, 1986), which were previously assigned to the genus Calyptogena Dall, 1891, and also for two new species, A. southwardae and A. novacula. The most characteristic features of Abyssogena are an elongate shell up to about 280 mm in length; a pallial line starting from the ventral margin of the anterior adductor scar; secondary pallial attachment scars developed dorsal to the pallial line; radially arranged hinge teeth with a reduced anterior cardinal tooth in the right valve; and presence of an inner ctenidial demibranch only. Abyssogena occurs in deep water from 2,985 to 6,400 m and is distributed in the Pacific and Atlantic Oceans at cold seeps along continental margins and hydrothermal vents at mid-oceanic ridges. Some species have a remarkably wide geographic distribution; A. southwardae is present throughout the Atlantic and A. phaseoliformis is present in Japan, Kuril-Kamchatka, as well as Aleutian Trenches. No fossils of Abyssogena are known.