“Ilyphagus antarcticus n. sp.
Figs. 22 a-22e
Material. Weddell Sea, in 650 m: Station 68-1 (holotype, USNM 46823).
Description. The body is long and truncate and measures 18 mm long and 2.3 mm wide at the anterior end, or widest part, of 20 setigers and 1.2 mm wide in the posterior constricted region. The anterior end is rounded except for a midventral incision. A pair of slender setal fascicles of cage setae emerges from each side directed far forward in front of the body; their free ends overlap at their mid-lengths. Each fascicle has 10 very slender long transversely barred setae, in which the bars are 11/22 times as long as they are wide (Figure 22b). The oral aperture is a vertical slit between the bases of the cage setae. The oral apparatus could not be examined because of the fragile condition of the specimen. The body is sparsely covered with short trancate papillae (Figure 22a).
The remaining parapodia have shorter setae directed laterally. On setigers 2-4 or 5 the setae are directed laterally. Farther back the parapodia approach the ventrolateral line so that the dorsum is convex and the ventrum flat. The last 20 segments are shorter than the more anterior ones. In other respects they are similar. Notosetae are of one kind, cross barred and simple (Figure 22c), only a few in a fascicle. Neurosetae are thicker and shorter, vaguely obliquely striated, and basally slightly expanded subdistally and terminate distally in long acute hyaline tips (Figure 22d). There are 3-5 neurosetae in a fascicle, and they are all similar except that the posterior ones tend to have shorter tips (Figure 22e). The posterior end of the body is plain, without visible papillae or lobes.
Remarks. Ilyphagus antarcticus differs from other species of the genus in that neurosetae are sub-distally expanded and the epithelium is sparsely instead of thickly papillated. The papillae are unusually short and obscure.”
(Hartman, 1978)
