Harmothoe vesiculosa Ditlevsen 1917

Harmothoe vesiculosa Ditlevsen, 1917

(Figs. 3, 32A–J)

Harmothoe vesiculosa Ditlevsen, 1917: 34, Pl. 1, Fig. 10, textfigs. 16–17; Fiege & Barnich (in press).

Type material. Harmothoe vesiculosa, lectotype (af, in rather poor condition), ZMUC-POL-1666, “Thor”- Expedition, SW of Ireland, 49°25’N 11°20’W, 25 June 1905, 1180 m.

Additional material. NE Atlantic: 1 spm., SMF 16991, VITAL-Expedition, “Atalante” St. V 20 (ROV “Victor” dive 190), 46°15’N 4°42’W, Bay of Biscay, Canyon de Belle Île, 1180 m, 01 September 2001, on Madrepora oculata, leg. H. Zibrowius.

(For further material see Fiege & Barnich, in press).

Diagnosis. Anterior pair of eyes dorsolateral at widest part of prostomium. Elytral margin with short papillae; surface with conical, blunt microtubercles; macrotubercles conical, blunt, in a dense row near posterior margin; macrotubercles rather small, but still distinctly larger than largest microtubercles.

Description (based on additional specimen SMF 16991, since lectotype in poor condition).

Body with 41 segments. At anterior end (Fig. 32A), prostomium bilobed, with distinct cephalic peaks; ceratophore of median antenna in anterior notch, lateral antennae inserted ventrally, styles of antennae papillate, tapering to filiform tip; anterior pair of eyes situated dorsolaterally at widest part of prostomium, posterior pair dorsally near hind margin of prostomium; palps papillate, tapering.

Tentaculophores inserted laterally to prostomium, each with two notochaetae and a dorsal and ventral tentacular cirrus, styles of cirri papillate, tapering to filiform tip. Second segment with first pair of elytra, biramous parapodia, and long buccal cirri. Following segments with tapering, short ventral cirri.

Fifteen pairs of elytra, covering dorsum, on segments 2, 4, 5, 7, then on every second segment to 23, 26, 29, 32; last nine segments cirrigerous; elytral margin with short papillae; surface with conical, blunt microtubercles; macrotubercles conical, blunt, in a dense row near posterior margin; macrotubercles rather small, but still distinctly larger than largest microtubercles (Fig. 32B,C). Cirrigerous segments with distinct dorsal tubercles; dorsal cirri with cylindrical cirrophore, style papillate, tapering to filiform tip.

Parapodia biramous; notopodia with elongate acicular lobe; neuropodia with elongate prechaetal acicular lobe with digitiform supra-acicular process; neuropodial postchaetal lobe shorter than prechaetal lobe, rounded; tips of noto- and neuroacicula penetrating epidermis (Fig. 32D). Notochaetae stouter than neurochaetae, with distinct rows of spines and blunt tip (Fig. 32E,F); neurochaetae with distinct rows of spines, mostly bidentate with slender secondary tooth, some lower unidentate (Fig. 32G–J).

Measurements. H. vesiculosa, lectotype, ZMUC-POL-1666: L 8 mm, W 4 mm, for 18 segments (af). Specimen figured, SMF 16991 (Fig. 32A–J): L 24 mm, W 6 mm for 41 segments.

Distribution. North Atlantic and Mediterranean Sea. Confirmed records from the Northwest Atlantic, (not covered here) showed that the species occurrs in the North Atlantic in general.

Habitat. Associated with cold water corals, in 538 to 1180 m in the Northeast Atlantic and Mediterranean; specimens from the Northwest Atlantic found down to 3025 m.