Ophelina Örsted, 1843
Ophelina cf cylindricaudata (Hansen 1878, sensu Hartmann-Schöder and Rosenfeldt, 1989)
Voucher specimens. Sea Lion: Station 24MFB; Easting: 570482; Northing: 4540294; 453 m.
Station 51MFC; Easting: 566485; Northing: 4530300; 436 m. Station 53MFB; Easting: 564490; Northing: 4528310; 444 m.
Diagnosis. Body long, linear, 10.5 -12mm long (inclusive of 1.3-1.5mm length of anal funnel) and 0.75-0.9mm wide; segments number 28 (irrespective of the size of the specimens); colour in alcohol yellow; body with longitudinal ventral groove; last four chaetigers characteristically short and crowded (Plate 1c). Prostomium conical, longer than wide, sharply pointed, with a small palpode and a pair of large, well-developed, reddish to brown nuchal organs (Plate 1b.). Branchiae cirriform, 8 pairs present on chaetigers 2-9 (well developed in chaetigers 2-7, very small and easily overlooked on chaetigers 8-9) (Plate 1a.), absent from mid-body region, 5 pairs present in the posterior region on chaetigers 19-24 (Plate 1c.), last four crowded chaetigers without branchiae. Anal cylinder long, smooth or faintly and irregularly ringed, with the dorsal edge longer than the ventral edge (Plate 1d.); ventral filament of anal tube missing, but small scar can be detected (Plate 1d.).
Remarks. Hansen (1878) described Ophelina cylindricaudata (as Ammotrypane cylindricaudatus) from two specimens collected in 763m and 911 m off the coast of Norway. Hartmann-Schröder and Rosenfeldt (1989, 1991) recorded the species from the Antarctic accepting the description and illustration provided by Stop-Bowitz (1945). However, it is possible that the Antarctic species is not the same as O. cylindricaudata (Hansen), which has been recorded primarily from Arctic waters and further analysis, including molecular techniques encompassing additional material from both Arctic and Antarctic waters is necessary before a conclusion can be reached.
Distribution. O. cylindricaudata is known from Arctic and Antarctic Seas, 7-4663 m; Southern Ocean material of O. cylindricaudata sensu Hartmann-Schröder and Rosenfeldt (1989) was recorded from ca. 65-600 m, Falkland Islands.