Terebellides

Schüller, Myriam & Hutchings, Pat, 2013, New species of Terebellides (Polychaeta: Trichobranchidae) from the deep Southern Ocean, with a key to all described species, Zootaxa 3619, pp. 1-45 : 33-35

Terebellides sp. D

Figs 27 , 28

Material examined: DZMB-HH 6136, ANDEEP II St. 138-10, GKG (ZMH-26015) Description:

Single individual 8 mm in length, 0.6 mm in width, incomplete with 18 thoracic chaetigers and about 15 abdominal chaetigers.

Head region: Tentacular membrane folded, expanded, and somewhat erect on dorsum of head region, reminiscent of an anemone ( Figs 27 , 28 E, F). Lower lip rectangular, folded upwards, laterally expanded but rather narrow anteriorly. Tentacles short simple ones and long ones with expanded tips present underlining the appearance of an anemone.

Branchiae: Three branchial lobes present (uncertain if fourth one is lost or only three present), all of similar length, posterior one slightly shorter, free from each other, lamellae broad, but compact, with very long fleshy filamentous tips ( Fig. 27 A). Annulation of branchial stem not determinable.

Anterior chaetigers: First chaetiger’s notopodia only slightly reduced in size.

Geniculate hooks: Present on TC-6 (segment 8) only. About 4 or 5 per side, hardly protruding but with very prolonged tips.

Lateral lobes: Present from TC-1–9, with TC-1=2=3>4=5>6=7<8=9 ( Fig. 27 B).

Ventral pads: Chaetigers 1–5 with glandular pads with elevated anterior margins, forming collars, chaetiger 6 much wider almost bell shaped, subsequent chaetigers narrower but still with elevated anterior margins. All strongly connected to the glandular areas surrounding the notopodia.

Nephridial papillae: Unkown.

MG staining pattern 1: Anterior solid to TC-4, striped from there. White bands and pronounced anterior margins absent. Noto- and neuropodia stain ( Fig. 28 ).

Pygidium: Unknown.

Remarks: This species is characterised by having an erect tentacular membrane, positioned dorsally on head region, lower lip very small, rectangular. Distinct lateral lappets from chaetiger 1–9, those of chaetigers 8–9 earshaped, larger than those of chaetigers 6–7 ( Fig. 28 D).

Habitat: Weddell Sea abyssal plain, in 4537 m.

Figures

FIGURE 27. Terebellides sp. D (ZMH- 26015), A—anterior thorax, dorsal, B—anterior thorax, ventro-lateral.

FIGURE 28. Terebellides sp. D (ZMH- 26015), MG-staining, A—thorax, ventral, B—anterior thorax, ventral, C—anterior thorax, ventral, D—anterior thorax, lateral, E—anterior thorax, dorsal, F—anterior thorax, lateral.