Harmothoe imbricata (Linnaeus, 1767)

Barnich, R. & Fiege, D., 2000, Revision of the Mediterranean species of Harmothoe Kinberg, 1856 Lagisca Malmgren, 1865 (Polychaeta: Polynoidae: Polynoinae) descriptions of a new genus and a new species, Journal of Natural History 34, pp. 1889-1938 : 1899-1900

Harmothoe imbricata (Linnaeus, 1767)

(fi gure 5A -D) Aphrodita imbricata Linnaeus, 1767: 1084 . Harmothoe imbricata: Fauvel, 1923: 55 , fi gure 18f -l; Bellan, 1964a: 23 [part]; Campoy, 1982: 61; Tebble and Chambers, 1982: 30, fi gures 7a, 9a, b, 31; Hartmann-SchroÈder, 1996: 46, fi gure 12; Chambers and Muir, 1997: 104, fi gure 26. Polynoe incerta Bobretzky, 1882: 187 , pl. 6: fi gure 1A -G. Harmothoe imbricata incerta: La Greca, 1949: 156 . Type material. Aphrodita imbricata , type material probably lost; Polynoe incerta , type material unavailable.

Additional material. 1 spm., St. 020306, July 1978, Islas Columbretes, en algas foto fi las ( Cystoseira ), 7 m, Coll. Campoy. 8 spms. (6af), 2 November 1996, E Âtang

Thau : Marseillan, Hafenmole Auûenseite, max. 1 m, leg. H. Zibrowius, SMF 9204 /8. 2 spms., 2 November 1996 , E Âtang de Thau : Marseillan, Hafenmole Auûenseite, max. 1 m, leg. H. Zibrowius, SMF 9238 /2. 2 spms., Gyf, 29 May 1953 ,

. 349, 42ss59¾N, 6ss23¾E, Port Cros, Coll. PeÂreÁs indeÂt. 1 spm., St. 45, Aegean Sea, Gulf of E Âvvoia leg. Arvanitidis, identi fi ed as H. fraserthomson i, MNHN A 943.

Diagnosis. Anterior pair of eyes beneath cephalic peaks. Elytra: margin with fringing papillae; surface covered by conical microtubercles and few scattered papillae, with a row of drop-like pointed macrotubercles near posterior margin. Dorsal and ventral tentacular cirri and dorsal cirri papillate, swelling subdistally then abruptly tapering to fi liform tip.

Description. Prostomium bilobed, with distinct cephalic peaks; median antenna with large ceratophore in anterior notch, style papillate, swelling subdistally then abruptly tapering to fi liform tip; lateral antennae with small ceratophores inserted IG. 5. Harmothoe imbricata (2 November 1996, E Âtang de Thau, SMF 9238/2). (A) Anterior end; styles of tentacular cirri and of left dorsal cirrus from chaetiger 3 missing; dorsal view; (B) right middle elytron; (C) detail of posterior margin of same; (D) style of dorsal cirrus (scales 5 1 mm for A, B; 250 M m for C; 500 M m for D).

ventrally and with short, papillate, tapering styles; palps papillate, shorter than median antenna and tentacular cirri; anterior pair of eyes anteroventrally beneath cephalic peaks, posterior pair dorsally near hind margin. Tentaculophores inserted laterally to prostomium, each with one or two chaetae and a pair of papillate, dorsal and ventral tentacular cirri swelling subdistally then abruptly tapering to fi liform tip. Second segment with fi rst pair of elytra, biramous parapodia, and long ventral buccal cirri, similar to tentacular cirri (fi gure 5A).

Fifteen pairs of elytra; elytral margin with fringing papillae; surface covered by conical microtubercles and few scattered papillae, with a row of drop-like pointed macrotubercles near posterior margin; elytra brownish in alcohol with central area being distinctly lighter (fi gure 5B, C). Styles of dorsal cirri papillate, swelling subdistally then abruptly tapering to fi liform tip, extending beyond neurochaetae, each cirrus slightly pigmented basally and with two pigmented bands distally (fi gure 5D); styles of ventral cirri with few papillae, shorter than neuropodia, tapering.

Parapodia biramous, both rami with single aciculum penetrating epidermis; notopodia with short, rounded presetal and longer, pointed postsetal acicular lobe, neuropodia with subconical presetal acicular lobe with digitiform supra-acicular process and shorter rounded postsetal lobe. Notochaetae stouter than neurochaetae, with distinct rows of spines and blunt tips; neurochaetae with distinct rows of spines only in distal part and bidentate tips with secondary tooth, some lower unidentate.

Remarks. (1) The elytra of Harmothoe imbricata may be confused with those of H. fraserthomson i and H. fragilis (see fi gures 5B, C, 7B, C, 11B, C). However, in H. fraserthomson i the elytral margin is smooth and the macrotubercles are rounded, without pointed tips, and not only present near the posterior margin, but also scattered over the surface; macrotubercles of H. fragilis are not prominent, but instead are fl attened discs situated near the posterior margin. Moreover, H. fraserthomsoni and H. fragilis have the anterior pair of eyes situated dorsolaterally on the widest part of the prostomium (fi gures 7A, 11A), and not anteroventrally beneath the cephalic peaks, as in H. imbricata (fi gure 5A).

(2) La Greca (1949) established the subspecies Harmothoe imbricata incerta based on material of Polynoe incerta Bobretzky, 1882 from the Black Sea. According to La Greca, members of this subspecies are very similar to H. imbricata , but their elytra have no macrotubercles and show a different pigmentation pattern. Unfortunately this material was not available and other specimens from this area could not be obtained, thus, the presence or absence of macrotubercles could not be veri fi ed. As macrotubercles of H. imbricata are easily overlooked, and elytral pigmentation pattern varies, we tentatively consider specimens referred to Polynoe incerta to be H. imbricata .

Measurements. Largest specimen found and fi gured herein: L 16 mm, W 3.5 mm for 37 chaetigers.

Distribution. Mediterranean Sea: Western Mediterranean, Aegean Sea; also reported from the Adriatic Sea (Pozar-Domac, 1978), the Eastern Mediterranean (Fauvel, 1937) and the Black Sea (Bobretzky, 1882; La Greca, 1949; Rullier, 1963; Marinov, 1964). Elsewhere: recorded from the Arctic and the northern hemisphere (Hartmann-Schr oÈder, 1996).

Habitat. Between stones, algae, Posidonia rhizomes, coralligeÁne, coastal mud; from 1 to 40 m depth.