Polaruschakov polaris (Uschakov 1957)

Polaruschakov polaris (Uschakov)

Macellicephala polaris Uschakov, 1957:1664, 1672, fig. 5.—Knox, 1959:114.—Rcyss. 1971:250.

Macellicephala arctica Knox, 1959:106, 114, pl. 1: figs. 1–6.—Reyss, 1968:323 [part]; 1971:252 [part].—Levenstein, 1972: 172 [part].

Macellicephala (Macellicephala) polaris.—Hartmann-Schröder, 1974:76, 84.

Marcellicephala (Sinantenna) arctica.—Hartmann-Schröder, 1974:80, 84 [part].

MATERIAL EXAMINED.—Polar Basin, north of Wrangel Island, 77°44.2′N, 189°42′E, 2245 m, silt, pebbles, broken stones, SP-2, sta. 2. 22–23 May 1950, holotype of Macellicephala polaris (ZIASL 1009).

DESCRIPTION.—Length of holotype of M. polaris 16 mm, width with parapodia 6 mm, width with setae 9 mm, segments 25, last ones very small. According to Knox (1959), length of holotype of M. arctica 8.5 mm, width with parapodia 1.4 mm, width with setae 3.3 mm, segments 22. Body colorless. Prostomium deeply bilobed, forming globular lobes; palps long, tapered, smooth (Figure 32a). Eyes lacking (pair of very large eyes with outline of lenses but no pigment, according to Knox, 1959, for M. arctica). Dorsal and ventral tentacular cirri sub-equal in length, shorter than palps, tapered, smooth (papillate, according to Knox, 1959). Without distinct facial tubercle. Paired scalelike lobes on segment 6, wide, thickened, soft, subrectangular (Figure 32a). Notosetae few in number (2–6), more slender than neurosetae, with rather widely spaced spinous rows and blunt rounded tips (Figure 32e; Uschakov, 1957, fig. 5c); notosetae with 2 rows of spines (according to Knox, 1959, pl. 1: figs. 3,4). Neurosetae numerous, transparent, slightly expanded and flattened distally, with bilateral series of widely spaced spines and blunt rounded tips (Figure 32f; Uschakov, 1957, fig. 5D; Knox, 1959, pl. 1: figs. 5,6). Dorsal cirri with long, tapered styles extending beyond tips of neuropodia (Figure 32a,c,d). Dorsal tubercles on cirrigerous segments small, subconical. Nephridial papillae small, distinct after segment 10.

DISTRIBUTION.—Arctic, in 730 (or less?) to 2245 meters.