Harmothoe abyssicola Bidenkap, 1894

Barnich, Ruth & Fiege, Dieter, 2009, Revision of the genus Harmothoe Kinberg, 1856 (Polychaeta: Polynoidae) in the Northeast Atlantic, Zootaxa 2104 (1), pp. 1-76 : 9-15

Harmothoe abyssicola Bidenkap, 1894

( Figs. 3 ; 6A–L )

Harmothoe abyssicola Bidenkap, 1894a: 5 ; ( 1894b): 59, pl. 2.

Harmothoe borealis: Loshamn (1980 , unpubl.): 124, fig. 59. [see remark below].

Type material. Harmothoe abyssicola : 5 syntypes, ZMO C4671–4675 , Norway, Skraaven (Lofoten), 200–300 fms, leg. M. & G.O. Sars. 5 syntypes, ZMO C2030 , Norway, Vallø (Oslofjorden), 200–230 fms, leg. M. Sars.

Additional material. NE Atlantic: 1 spm. (af), SMF 17291, Vigdis 2005 St. IT 4-S, 11 June 2005, 61.39112° N, 2.07830° E, 283 m, ded. A. Sikorski .

Diagnosis. Anterior pair of eyes dorsolateral at widest part of prostomium. Elytral margin with scattered papillae; surface with conical, rounded to elongate, microtubercles; macrotubercles few, conical to globose, near posterior margin. Neurochaetae fragile, smooth or with reduced rows of spines, tips unidentate or minutely bidentate.

Description (based on syntypes ZMO C2030).

Body with up to 36 segments. At anterior end ( Fig. 6A ), prostomium bilobed, with distinct cephalic peaks; ceratophore of median antenna in anterior notch, lateral antennae inserted ventrally, styles of antennae papillate, tapering; anterior pair of eyes situated dorsolaterally at widest part of prostomium, posterior pair dorsally near hind margin of prostomium; palps papillate, tapering.

Tentaculophores inserted laterally to prostomium, each with two notochaetae and a dorsal and ventral tentacular cirrus, styles of cirri papillate, tapering. Second segment with first pair of elytra, biramous parapodia, and long buccal cirri. Following segments with tapering, short ventral cirri, anterior cirri with scattered papillae.

Fifteen pairs of elytra, covering dorsum, on segments 2, 4, 5, 7, then on every second segment to 23, 26, 29, 32; last four segments cirrigerous; elytral margin with scattered papillae; surface with conical, rounded to elongate, microtubercles; macrotubercles few, conical to globose, near posterior margin ( Fig. 6B–C ). Cirrigerous segments with distinct dorsal tubercles; dorsal cirri with cylindrical cirrophore, style papillate, tapering.

Parapodia biramous; notopodia with elongate acicular lobe; neuropodia with elongate prechaetal acicular lobe with digitiform supra-acicular process; neuropodial postchaetal lobe shorter than prechaetal lobe, rounded; tips of noto- and neuroacicula penetrating epidermis ( Fig. 6D ). Notochaetae stouter than neurochaetae, with distinct rows of spines and blunt tip ( Fig. 6E–G ); neurochaetae fragile, smooth or with reduced rows of spines, tips mainly unidentate, some upper neurochaetae minutely bidentate ( Fig. 6H–L ).

Measurements. Syntypes, ZMO C2030: 1 cs with regenerating end, L 6 mm, W 3.5 mm for 23 segments; 1 cs, juvenile, L 5.5 mm, W 2.5 mm for 22 segments; 1 af with everted pharynx ( Fig. 6A ), L 6.5 mm, W 3 mm for 22 segments; 1 af, L 10 mm, W 3.5 mm for 25 segments; 1 mf, L 4.5 mm, W 3.5 mm for 14 segments. Syntypes, ZMO C4671: 1 af, L 7.5, W 4 mm for 18 segments; C4672, 1 af, L 6 mm, W 3 mm for 20 segments;

C4673, 1 af, L 12 mm, W 5 mm for 20 segments; C4674, 1 af, L 12.5 mm, W 4 mm for 25 segments; C4675, 1 af, L 8.5 mm, W 3.5 mm for 21 segments.

Remarks. M. Sars (1869) listed the new species Polynoe (Eunoa) abyssicola , but without giving a description. Since Bidenkap (1894) was the first to describe the species properly, his authorship has priority.

Evarne johnstoni McIntosh, 1876 and Polynoe borealis Théel, 1879 are described to have slender neurochaetae with very faint rows of spines, a character also found in H. abyssicola (see McIntosh 1876b and Théel 1879). Since the type specimens of both species, E. johnstoni (BMNH 1921.5.1.483) and P. borealis (SMNH-Type-2375), lack elytra and their descriptions are insufficient, these species are considered indeterminable.

Specimens occurring in the Northeast Atlantic and showing slender neurochaetae with reduced rows of spines, but differing from H. abyssicola by their elytra with microtubercles only and numerous long marginal papillae are referred here to H. fernandi n. sp.

Distribution. Confirmed along the Norwegian coast; according to Loshamn (1980, unpubl.) occurring in the Arctic and in the Northeast Atlantic down to the Skagerrak.

Habitat. Unknown, in 364–546 m.

Figures

FIGURE 3. Identification characters of Harmothoe impar, H. clavigera, H. rarispina, H. extenuata, H. fragilis, H. vesiculosa, H. abyssicola, and H. mariannae n. sp.

FIGURE 6. Harmothoe abyssicola (syntype, af with everted pharynx, ZMO C2030). (A) anterior end; styles of median antenna, left dorsal tentacular cirrus, and left dorsal cirrus missing; everted pharynx not figured; (B) right middle elytron from unknown segment, free in vial; (C) micro- and macrotubercles from same; (D) right cirrigerous parapodium from unknown segment, free in vial, posterior view, style of ventral cirrus missing; (E) short notochaeta; (F) long notochaeta; (G) tip of same; (H) middle neurochaeta; (I) tip of same; (J) tip of unidentate upper neurochaeta; (K) tip of bidentate upper neurochaeta; (L) distal part of lower neurochaeta. (Scales: A, B = 1 mm; C = 100 µm; D = 500 µm; E, F, H = 250 µm; G, I–L = 50 µm).