Ophelina ammotrypanella, Schüller, Myriam, 2008

Schüller, Myriam, 2008, New polychaete species collected during the expeditions ANDEEP I, II, and III to the deep Atlantic sector of the Southern Ocean in the austral summers 2002 and 2005 — Ampharetidae, Opheliidae, and Scalibregmatidae, Zootaxa 1705, pp. 51-68 : 60

Ophelina ammotrypanella sp. nov.

( Fig. 4 E–F)

Holotype. ANDEEP I – II; Weddell Sea, Antarctic Peninsula, Sta. 131-3, 0 5 March 2002, 65°19.83’S, 51°31.62’W, 3049-3050 m, EBS, ZMH P- 24757.

Paratypes. ANDEEP III, Weddell Sea, South Orkney Islands, Sta. 154-9, 30 March 2005, 61°49.13'S, 47°27.51'W, 1970 m, EBS, 8 specimens, ZMH P- 24758.

Additional material. 131-3 (1), 16-10 (4), 78-9 (10), 81-8 (4), 110-8 (4), 121-11 (7).

Etymology. The name refers to the close resemblance of this species to Ammotrypanella arctica which only differs from O. ammotrypanella sp. nov. in the lack of branchiae in anterior and median segments.

Diagnosis. The species can be recognized by the enlarged branchiae being limited to the third body quarter and an anal tube without a ventral cirrus.

Description. Holotype complete, 30.5 mm long and 2 mm wide for 45 chaetigers.

A large species of about 14–31 mm length and 1–2 mm width for 32–45 chaetigers. Color in alcohol a light tan.

Prostomium conical with a distinct palpode. Peristomium forming a ring around the lips. Nuchal organs indistinct, but present. Eyes absent ( Fig. 4 E).

First subsequent segment achaetous. Following segments with small, reduced parapodia. Anterior chaetigers with apparent annulation, this and segmental sutures fading towards median body region. Segmental sutures more apparent in posterior body region again.

Chaetae simple capillaries throughout, anterior ones long and curved, median ones short, and posterior ones long and straight.

Branchiae present in anterior and median chaetigers, very small and indistinct in first body half. Very large, somewhat limbate branchiae in third quarter of body, up to 15 of them present, lacking in posterior chaetigers.

Posterior chaetigers laterally flattened and strongly decreasing in size. Pygidium with robust anal tube. Margin of anal tube with numerous fine cirri, ventral cirrus lacking ( Fig. 4 F).

Remarks. The species is most similar to Ophelina setigera ( Hartman, 1978) . Both species share the prolonged chaetae in anterior segments and lack a ventral cirrus on the anal tube. The anterior branchiae of O. ammotrypanella sp. nov. are, however, smaller and less distinct than those of O. setigera . At first sight the species is therefore reminiscent of Ammotrypanella arctica .

Distribution. Southern Atlantic to Atlantic sector of Southern Ocean and Antarctic Peninsula, 2182–4720 m

Figures

FIGURE 4. A – B Ammotrypanella mcintoshi sp. nov. A. anterior segments, B. posterior segments; C – D. Ophelina robusta sp. nov. C. anterior segments, D. posterior segments; E – F. Ophelina ammotrypanella sp. nov. E. anterior segments, F. posterior segments.