Ammotrypanella princessa, 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 : 59-60

Ammotrypanella princessa sp. nov.

( Fig. 3 F–G)

Holotype. ANDEEP I – II, Weddell Sea, Antarctic Peninsula, Sta. 134-4, 0 9 March 2002, 65°19.20’S, 48°3.81’W, 4066–4069 m, EBS, ZMH P- 24755.

Paratypes. Scotia Sea northeast off Elephant Island, Sta. 42-2, 27 January 2002, 59°40.29’S, 57°35.43’W, 3683–3690 m, EBS, 1 specimen, Weddell Sea, Antarctic Peninsula, Sta. 135-4, 11 March 2002, 65°0.06’S, 43°1.19’W, 4678 m, EBS, 1 specimen, ZMH P- 24756.

Additional material. 16-10 (1), 78-9 (1), 81-8 (1), 121-11 (1), 153-7 (1).

Etymology. The name refers to the crown-shaped prostomium and the long, slightly bent chaetae along the anterior and median body that give the species a noble, feminine look.

Diagnosis. Distinguishing characters of the species are the shape of the prostomium, the presence of relatively long chaetae in the median body region, and the smooth margin of the anal tube in combination with the presence of a ventral cirrus.

Description. Holotype complete, body long and thin, 11 mm long and 1 mm wide for 35 chaetigers.

Length of species 5–11 mm, width about 0.2–1 mm; number of chaetigers 33–35. With ventral groove along whole length of body. Posterior body region laterally flattened. Color in alcohol white to a light tan.

Prostomium crown-shaped to conical, with a short palpode. Peristomium limited to the lips. First following segment achaetous. Nuchal organs apparent as lateral grooves, eyes absent ( Fig. 3 G).

Anterior eight parapodia button-shaped with prolonged, stiff chaetae in bushy fascicles. Median parapodia less distinct, embedded in lateral groove, with few long, slightly bent chaetae. Posterior parapodia prominent, chaetae long and straight. All chaetae simple.

Branchiae present in varying numbers in third quarter of body (about chaetigers 23–30), all of similar length, flat with wide base, tapering to top.

Posterior abranchiate chaetigers reduced in length, close to each other. Pygidium with anal tube; about as long as last six chaetigers, opening slightly ventrally; posterior margin smooth, with short and stout ventral cirrus ( Fig. 3 F).

Remarks. The species stands out by its median parapodia. These are more distinct than in Ammotrypanella arctica and A. cirrosa sp. nov., with long, slightly bent chaetae. Therefore, the difference in chaetation between the anterior and median body region is less apparent. The prostomium is not completely conical, its form rather reminds of a crown. A. princessa sp. nov. and A. cirrosa sp. nov. have in common the ventral cirrus on the posterior margin of the anal tube. The margin of the anal tube, however, is smooth in A. princessa sp. nov.

Distribution. Southern Atlantic to Atlantic sector of Southern Ocean and Antarctic Peninsula, 2014–4720 m.

Figures

FIGURE 3. A – B Ammotrypanella cirrosa sp. nov. A. entire animal, B. posterior segments; C – E. Ammotrypanella arctica McIntosh 1879 C. anterior segments dorsal view, D. anterior segments lateral view, E. posterior segments, F – G Ammotrypanella princessa sp. nov. F. posterior segments, G. anterior segments.