Diplocirrus normani (McIntosh, 1908) McIntosh, 1908

Salazar-Vallejo, Sergio I. & Buzhinskaja, Galina, 2011, Revision of Diplocirrus Haase, 1915, including Bradiella Rullier, 1965, and Diversibranchius Buzhinskaja, 1993 (Polychaeta, Flabelligeridae), ZooKeys 106, pp. 1-45 : 30-32

Diplocirrus normani (McIntosh, 1908) comb. n. Fig. 10

Stylarioides normani McIntosh 1908:542-543, Pl. 12, Figs. 3, 8.

Stylarioides longisetosus von Marenzeller 1892:426-427 (non von Marenzeller, 1890).

Diplocirrus longisetosus : Haase 1915:200-202, Textfigs. 6-7 (partim); Støp-Bowitz 1948a:30-33, Fig. 8; Støp-Bowitz 1948b:38-39, map (non von Marenzeller, 1890).

Type material.

Barents Sea. Holotype of Stylarioides normani (BMNH-1921.5.1.2646), Finmark, Northern Norway, Stat. 49, 1890, C. Norman, coll. (anterior fragment, dried-out, 7.5 mm long, 1.5 mm wide, cephalic cage 3 mm long, 14 chaetigers; right chaetiger 10 previously removed).

Additional material.

Barents Sea. Two specimens (ECOSUR), White Sea, Russia, 5 Aug. 1999, A. Filippova, coll. (complete specimen used for redescription; anterior fragment 6 mm long, 1.5 mm wide, cephalic cage 2 mm long, 14 chaetigers). One specimen (ECOSUR), White Sea, Russia, 15 m, Jul. 1999, A. Filippova, coll. (anterior fragment 3 mm long, 1 mm wide, cephalic cage 2.3 mm long, 11 chaetigers). Two specimens (ECOSUR) complete, slightly damaged, Kandalalsha Bay, White Sea, Russia, 40 m, mud, 1 Aug. 2004, A. Zhadan, coll. (specimen with anterior end exposed used for description; 5.0-5.5 mm long, 0.8-1.0 mm wide, cephalic cage 1.0-1.3 mm long, 20-21 chaetigers; exposed anterior end 0.7 mm long). Northwestern Atlantic Ocean. Several specimens (USNM-48491), Cape Cod Bay, Massachusetts, Stat. 1424, 35.1-33.6 m, 19 Nov. 1968, C.D. Long. Coll. Id.

Description.

Non-type specimen (ECOSUR) complete, yellowish gray. Body club-shaped, anteriorly swollen, slightly narrowing to chaetiger 13, then apparently regenerating the posterior, cylindrical region, tapering to posterior end (Fig. 10A); 12 mm long, 1.5 mm wide, cephalic cage 3 mm long, 25 chaetigers. Tunic papillated, with fine sediment particles. Papillae eroded, core and tips black, cirriform, sparse, fragile, about 7-8 transverse rows in median chaetigers, becoming longer dorsally (Fig. 10B); in median chaetigers about 1/5-1/6 as long as notochaetae.

Cephalic tube long, smooth, margin apparently smooth. Prostomium low, eyes not seen. Caruncle not seen. One palp remaining, thick, longer than remaining branchiae, longitudinal furrow shallow; palp keels reduced. Dorsal and ventral lips reduced, lateral lips thicker. Branchiae cirriform, most lost, sessile on branchial plate, arranged in two concentric rows, distal row continuous with 4 thicker filaments bases, proximal row discontinuous, filaments probably thinner, lower filaments bases smaller. Nephridial lobes very thin, long, placed below the posterior row lateral filaments.

Cephalic cage chaetae ¼ as long as body length, or twice as long as body width. Chaetigers 1-2 involved in the cephalic cage; chaetae arranged in short dorsolateral lines, 6-8 noto- and 4-6 neurochaetae per bundle. Anterior dorsal margin of first chaetiger papillated, black; anterior chaetigers without especially long papillae. Chaetigers 1-3 of about the same length. Post-cephalic cage chaetigers not elongated. No chaetal transition from cephalic cage to body chaetae, all neurochaetae similar. Gonopodial lobes present in chaetiger 5, low, rounded, black, covered by small papillae (Fig. 10C).

Parapodia lateral, poorly developed, chaetae emerge from the body wall (Fig. 10D); median neuropodia ventrolateral. Notopodia 2-3 with very low conical lobes directed forward, remaining notopodia less prominent. Neuropodia 2-5 with low conical chaetal lobes. Noto- and neuropodia distant to each other.

Median notochaetae arranged in a transverse horizontal C-shaped pattern; all notochaetae multiarticulated capillaries, short articles basally and distally, long medially (Fig. 10E). About 10 (-12) chaetae per bundle, at least twice as long as body width. All neurochaetae multiarticulated capillaries, short, poorly-defined articles along basal half or 2/3 chaetal length, better-defined, medium-sized and then long articles along the rest of chaetae (Fig. 10F), tips straight, arranged in a transverse line, 9-10 per bundle.

Posterior end tapering to a rounded lobe; pygidium with anus terminal, blackish, without anal cirri.

Remarks.

Diplocirrus normani (McIntosh, 1908), comb. n. was regarded as a junior synonym of Diplocirrus longisetosus (von Marenzeller, 1890) by Haase (1915:200) because they are very similar. As stated above, they also resemble Diplocirrus micans Fauchald, 1972, though the latter separates from the other two species because it lacks gonopodial lobes and its neurochaetae have long articles. Thus, once Diplocirrus longisetosus has been restricted, these species differ regarding coloration of body, papillae and gonopodial lobes, and because of the relative resolution of neurochaetal basal articles. Thus, in Diplocirrus normani , although the body is grayish, papillae and gonopodial lobes are darker or blackish, and neurochaetal basal articles are poorly-defined, whereas in Diplocirrus longisetosus , on the contrary, the papillae and gonopodial lobes are pale, and the basal articles of neurochaetae are well-defined.

Distribution.

Originally described from Finmark, Northern Norway, Barents Sea. It ranges along Northeastern and Northwestern Atlantic areas, in shallow water.