Harmothoe fraserthomsoni McIntosh, 1897

Barnich, Ruth & Fiege, Dieter, 2009, Revision of the genus Harmothoe Kinberg, 1856 (Polychaeta: Polynoidae) in the Northeast Atlantic, Zootaxa 2104 (1), pp. 1-76 : 39

Harmothoe fraserthomsoni McIntosh, 1897

( Figs. 2 , 18A–J )

Harmothoe fraserthomsoni McIntosh, 1897a: 401 ; McIntosh (1900): 337, pl. 28 fig. 7, pl. 32 fig. 11, pl. 29 fig. 15, pl. 39 figs.4–6; Chambers & Muir (1997): 102, fig. 25; Barnich & Fiege (2000): 1903 , fig. 7A–C; Barnich & Fiege (2003): 42, fig. 18A–C.

Harmothoe Fraser-Thomsoni : Fauvel, 1923: 68, fig. 25a–e.

? Polynoe (Harmothoe) talismani Roule, 1898: 192 ; ( 1906): 29, pl. 3 fig. 14, pl. 4 figs. 21–22, pl. 7 figs. 57–58.

Type material. Harmothoe fraserthomsoni : holotype (dry), BMNH 1885.12.1.76), "Knight-Errant" St. 3, Färoe Channel Exp., off the Butt of Lewis , 3 August 1880, dredged, 53 fms .

Polynoe (Harmothoe) talismani : holotype (in poor condition), MNHN Type 049, "Talisman" St. 49, off Lanzarote (Canary Islands), 27 June 1883, dredged, 865–927 m.

Additional material. Mediterranean: 2 spms., SMF 12470, “ Prof. Th. Tissier 1959“, St. L 386, W Mediterranean, Alboran Sea, E of Cape Tres Forcas , 35°25’N, 2°44’W, 235–250 m, VP, Coll. Pérès indét .

(For further material see Barnich & Fiege 2000 and 2003).

Diagnosis. Anterior pair of eyes dorsolateral at widest part of prostomium. Elytral margin usually smooth (except for some scattered papillae in anteriormost elytra); surface covered by conical microtubercles; conical macrotubercles scattered on surface and near posterior margin (tend to disappear in more posterior elytra).

Description (based on additional specimens SMF 12470, since type material in rather poor condition).

Body with 38 to 40 segments. At anterior end ( Fig. 18A ), prostomium bilobed, with distinct cephalic peaks; ceratophore of median antenna in anterior notch, lateral antennae inserted ventrally, styles of antennae papillate, tapering to filiform tip; 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 to filiform tip. Second segment with first pair of elytra, biramous parapodia, and long buccal cirri. Following segments with tapering, short ventral cirri.

Fifteen pairs of elytra, covering dorsum, on segments 2, 4, 5, 7, then on every second segment to 23, 26, 29, 32; last six to eight segments cirrigerous; elytral margin usually smooth (except for some scattered papillae in anteriormost elytra); surface covered by conical microtubercles; conical macrotubercles scattered on surface and near posterior margin (tend to disappear in more posterior elytra) ( Fig. 18B,C ). Cirrigerous segments with distinct dorsal tubercles; dorsal cirri with cylindrical cirrophore, style papillate, tapering to filiform tip.

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. 18D ). Notochaetae stouter than neurochaetae, with distinct rows of spines and blunt tip ( Fig. 18E,F ); neurochaetae with distinct rows of spines, mostly bidentate with distinct secondary tooth, some upper and lower unidentate ( Fig. 18G–J ).

Measurements. Specimens figured, SMF 12470: L 22 mm, W 4 mm for 38 segments ( Fig. 18A ); L 28 mm, W 5 mm for 40 segments ( Fig. 18B–J ).

Remarks. After having re-evaluated some specimens from the Mediterranean, we became aware that antennae and cirri of this species are minutely papillate in contrast to the statement given in Barnich & Fiege (2000 and 2003).

Distribution. North Atlantic and Mediterranean Sea.

Habitat. On hard substrates; from 53 to 927 m.

Figures

FIGURE 2. Identification characters of Leucia violacea, Harmothoe fraserthomsoni, Leucia nivea, Acanthicolepis asperrima, Harmothoe aspera, and H. serrata.

FIGURE 18. Harmothoe fraserthomsoni (additional specimens, SMF 12470: small spm., Fig. 18A; large spm., Figs. 18B–J). (A) anterior end; (B) left elytron from unknown segment; (C) detail of posterior margin of same; (D) right cirrigerous parapodium from segment 12, posterior view, style of dorsal cirrus not figured; (E) long notochaeta; (F) tip of same; (G) middle neurochaeta; (H) tip of same; (I) tip of upper neurochaeta; (J) tip of lower neurochaeta. (Scale: A = 1 mm; B = 2 mm; C = 250 µm; D = 500 µm; E, G = 250 µm; F, H–J = 100 µm).