Paranaitis benthicola, (KNOX, 1960)

Kato, Tetsuya & Pleijel, Fredrik, 2003, A revision of Paranaitis Southern, 1914 (Polychaeta: Phyllodocidae), Zoological Journal of the Linnean Society 138 (4), pp. 379-429 : 389-390

PARANAITIS BENTHICOLA ( KNOX, 1960) ( FIG. 5 )

Eulalia (Euphylla) benthicola Knox, 1960: 113 , figs 137–140.

Paranaitis benthicola: Pleijel, 1991: 258 .

Material examined

Holotype ( CMC AQ 3461 ), Chatham Rise, 43∞32¢S, 178∞38¢E, 540 m or deeper, 24 January 1954.

Description

Holotype lacking posterior end, 33 mm long, 2.3 mm wide, for 107 segments. Body colour of live specimens unknown. Preserved specimen uniformly pale. Body dorso-ventrally flattened. Prostomium anteriorly rounded, slightly wider than long, with distinct deep ligula ( Fig. 5A ). Paired antennae fusiform, c. 2/3 as long as prostomial width. Palps similar in shape to paired antennae, slightly longer. Eyes absent. Nuchal papilla fusiform, c. half as long as paired antennae, situated posteriorly in ligula. Nuchal organs retractile, laterally situated ( Fig. 5B ). Median part of proboscis with six rows of rounded tubercles. Distal most and proximal most part of proboscis, including terminal ring and paired large papillae inside ring, unknown.

Segments 1 and 2 fused dorsally. Cirri of segment 1, dorsal and ventral cirri of segment 2, and dorsal cirri of segment 3 cylindrical, long and tapered. Cirri of segment 1 reaching c. segment 6. Dorsal cirri of segment 2 reaching c. segment 8. Ventral cirri of segment 2 reaching c. segment 6. Dorsal cirri of segment 3 reaching c. segment 9. Segment 2 with 6–7 chaetae arising from ventral cirrophores ( Fig. 5A,B ). Segment 3 with small neuropodial lobes with c. 10 chaetae. Ventral cirri of segment 3 similar in shape to those on following segments but slightly smaller; anterior cirri gradually increasing in size. Aciculae in segments 2 and 3 unknown.

Dorsal cirri of median segments reniform, wider than long. Dorsal cirrophores distinct, symmetrical. Neuropodium with supra-acicular lobes longer than subacicular lobes, with c. 23 chaetae. Dorsal and ventral chaetae similar within single fascicle. Rostrum of chaetal shaft symmetrical, with short single main tooth on anterior and posterior sides. Ventral cirri oval with blunt ends, as long as, or longer than, neuropodia. Pygidial cirri and pygidial papilla unknown.

Habitat

540 m or deeper.

Distribution

Known only from the Chatham Rise, New Zealand.

Remarks

This species is known only from the holotype. It differs from other Paranaitis in the character combination long distal part of proboscis (more than 9/10 of total length of proboscis) covered by six rows of large tubercles, and symmetrical rostrum of chaetal shaft with single main tooth on both anterior and posterior side.

Figures

Figure 5. Paranaitis benthicola, holotype. A, anterior end, dorsal view. B, same, ventral view.