Pseudoscalibregma papilia, 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 : 62-65

Pseudoscalibregma papilia sp. nov.

( Fig. 5 A–E)

Holotype. ANDEEP I – II, South Sandwich Islands, Sta. 141-10, 23 March 2002, 58°25.08’S, 25°0.77’W, 2258–2313 m, EBS, ZMH P- 24761.

Paratypes. ANDEEP I – II, South Sandwich Islands, Sta. 141-10, 23 March 2002, 58°25.08’S, 25°0.77’W, 2258–2313 m, EBS, 2 specimens, ZMH P- 24762.

Additional material. 42-2 (3), 46-7 (2), 121-11 (1), 142-5 (1), 150-6 (5), 153-7 (1).

Etymology. The species is named after the shape of the posterior parapodia which resemble butterfly wings.

Diagnosis. The species can be recognized by prominent, almost foliose dorsal and ventral cirri in its posterior parapodia, distinctly rounded prostomial lobes and a rather smooth to irregularly wrinkled body surface.

Description. Holotype. complete, 6 mm long and 1 mm wide for 33 chaetigers.

A moderately large species of 5–12 mm length and 0.5–1 mm width. Number of chaetigers 26–33 ( Fig. 5 A). Color in alcohol white to a light tan. Body sometimes expanded in anterior region to about chaetiger 12.

Prostomium with two spherical lobes anterolaterally; no eyes, nuchal organs not apparent. Peristomium a single achaetous ring, well developed ( Fig. 5 B).

Body surface almost smooth, sometimes irregularly wrinkled, a scheme in annulation not apparent. Anterior parapodia with reduced parapodial lobes, dorsal and ventral cirri, these rapidly increasing in size in median region; posterior dorsal and ventral cirri of large size, almost foliose, ventral cirri larger than dorsal ones; interramal sense organs missing ( Fig. 5 C).

All parapodia with simple chaetae; furcate chaetae with unequal tynes covered by fine hairs, present from chaetiger 2 ( Fig. 5 D).

Pygidium terminal, formed by a ring of large tubercles carrying cirri of different lengths ( Fig. 5 E).

Remarks. The species is most similar to Pseudoscalibregma bransfieldium ( Hartman, 1967) which is also very common in the Southern Ocean ( Blake 1981). The two species have in common the moderately large size and the lack of a schematic annulation (unlike P. ursapium e.g. which is covered by prominent tubercles). Pseudoscalibregma papilia sp. nov. can easily be distinguished from P. bransfieldium by the lack of a prominent nuchal organ dorsally on the prostomium, the distinctly spherical form of the anterolateral prostomial lobes, and the exceptionally large size of the posterior dorsal and ventral cirri.

Distribution. Weddell Sea, Antarctic Peninsula, Drake Passage and South Sandwich Trench, 1970–3690 m

Figures

FIGURE 5. Pseudoscalibregma papilia sp. nov. A. entire animal, B. anterior segments, C. posterior parapodium, D. furcate chaetae, E. pygidium.