Macellicephaloides grandicirra Uschakov 1955

Macellicephaloides grandicirra Uschakov, 1955

Macellicephaloides grandicirra Uschakov. 1955:314, fig. 2a–d.—Levenstein, 1971b:26.—Hartmann-Schröder. 1974:81, 85.

MATERIAL EXAMINED.—Northwest Pacific, Kurile-Kamchatka Trench, Viliaz sta. 2217, 1953, 1 specimen (USNM 43624; ex change from ZIASL 2/789; identified by Uschakov).

DESCRIPTION.—Length of specimen from Vitiaz sta. 2217 (USNM 43624) 35 mm, width of body 6 mm, width including parapodia 16 mm, segments 17. According to Uschakov, length of largest specimen 65 mm, width including parapodia 25 mm, segments 17. Elytrophores small, situated close to dorsal bases of long parapodia (Figure 25a,g; Uschakov, 1955, fig. 2a). Dorsal tubercles lacking.

Bilobed prostomium with minute frontal filaments (on specimen examined; Figure 25a; not mentioned by Uschakov; sometimes absent, withdrawn or broken off?); style of median antenna long, extending posteriorly to segment 2; palps with cylindrical palpophores, slightly bulbous dorsally, with styles subequal in length to tentacular cirri. Cirrophores of ventral tentacular cirri longer than dorsal ones; styles rather short, tapered, shorter than median antenna (Figure 25a,b). Tentacular segment contributing to lobulated upper, lateral and lower lips of mouth (Figure 25a,b).

Stout notopodial acicular lobes extending to tips of neuropodia or slightly beyond (Figure 25a,b,g,h); in more posterior parapodia, notopodial acicular lobes extending far beyond neuropodia (Figure 25j). Neurosetae with slightly hooked tips (Figure 25i; Uschakov, 1955, fig. 2c). Dorsal cirri with greatly elongate, flattened, beltlike cirrophores extending far beyond neuropodia, with rather short styles; cirrophores of posterior segment shorter than neuropodia (Figure 25b,h,j; Uschakov, 1955, fig. 2a,b—separation of cirrophores and styles not indicated).

Pygidium clavate, tubular, medial to elongate parapodia of posterior two segments; parapodia of last segment with shorter dorsal cirrophores (styles missing; Figure 25j). Nephridial papillae short, wide, slightly raised, none especially enlarged (Figure 25g,h).

Pharynx with 4 large, rounded dorsal papillae (indicated as “d” on figures), 3 pairs of dorsolateral papillae, more dorsal pair (number 1 on figure) similar in size to dorsal papillae, middle pair (number 2) more elongate, and more ventral pair (number 3) smallest; pair of large collar-like ventrolateral folds (vF; Figure 25c–e; Uschakov, 1955, fig. 2d). Jaws consisting of single dorsal one formed of 3 fused parts and subtriangular ventral pair (Figure 25f; Uschakov, 1955, fig. 2e).

DISTRIBUTION.—Northwest Pacific (Kurile-Kamchatka Trench), in 8100 to 9950 meters.