Paranaitis

Kato, Tetsuya & Pleijel, Fredrik, 2003, A revision of Paranaitis Southern, 1914 (Polychaeta: Phyllodocidae), Zoological Journal of the Linnean Society 138 (4), pp. 379-429 : 389

REVISION OF PARANAITIS 389

papillae, situated at lateral margin of mouth ( Fig. 4B ; see remarks). Proximal-most part of proboscis covered with small rounded papillae; distal part unknown.

Segments 1 and 2 fused. Holotype lacking cirri of segment 1, dorsal and ventral cirri of segment 2, and dorsal cirri of segment 3 (ventral one of left side of segment 2 lacking distal part). Segment 2 with c. five chaetae arising from small neuropodial lobes fused to ventral cirrophores. Aciculae of segments 2 and 3 unknown.

Dorsal cirri of median segments nearly circular, about as long as wide ( Fig. 4C ). Dorsal cirrophores distinct, symmetrical. Neuropodial lobes long, with supra-acicular lobes longer than subacicular lobes, with 20–26 chaetae. Dorsal and ventral chaetae similar within single fascicle. Rostrum of chaetal shaft asymmetrical, with single main tooth almost entirely covered by many small teeth on anterior side, small tooth on posterior side. Ventral cirri oval, c. twice as long as wide, with rounded ends. Pygidial cirri and pygidial papilla unknown.

Habitat

5260 m.

Distribution

Known only from the type locality off the Iberian Peninsula.

Remarks

This species is known only from the holotype specimen, which is in poor condition. It differs from other Paranaitis in the character combination of nearly circular dorsal cirri, symmetrical dorsal cirrophores, distinct deep ligula of prostomium, and absence of eyes. We found paired large rounded papillae at the lateral margin of mouth opening ( Fig. 4B ). It is uncertain whether these represent nuchal organs or proboscis papillae, as the proboscis of the specimen is only slightly everted.

Figures

Figure 4. Paranaitis abyssalis, holotype. A, anterior end, dorsal view. B, same, with slightly everted proboscis, ventral view. C, median segments, dorsal view.