Figure 1 A–F
Hermadion magalhaensi Kinberg, 1856: 386; Kinberg (1857): pl. 6 fig. 32; Kinberg (1858): 22; Ehlers (1897): 15; Ehlers (1901 b): 43; Ehlers (1908): 46; Bergström (1916): 276; Augener (1932): 97; Barnich et al. (2006): 36. Hermadion longicirratus Kinberg, 1856: 386; Kinberg (1857): pl. 6 fig. 33; Kinberg (1858): 22.
Hermadion kerguelensis McIntosh, 1885: 105, pl. 11 fig. 5, pl. 12 fig. 1. Lagisca laevis Hartmann-Schröder, 1962: 60, fig. 5–8 [new synonymy]. Hermadion laevis: Orensanz (1974): 10.
Type material examined (see also respective material sections of Adyte hyalina (G. O. Sars, 1873) and Neopolynoe acanellae (Verrill, 1881) below). Hermadion magalhaensi Kinberg, 1856: SMNH Type- 401, 4 syntypes (1 cs, 3 af) with several elytra and parapodia free in vial, "Eugenie“ Expedition 1851 - 53, Chile, Magellan Strait, St.Yorkbay, 53 ° 34 'S 72 ° 20 'W, below stones of the littoral, near the river Bachelor.
Hermadion longicirratus Kinberg, 1856: SMNH Type- 384, holotype (cs in two fragments) "Eugenie“ Expedition 1851 - 53, Chile, Magellan Strait, St.Yorkbay, 53 ° 34 'S 72 ° 20 'W, below stones of the littoral, near the river Bachelor.
Hermadion kerguelensis McIntosh, 1885: BMNH 1885. 12.1. 88, 2 syntypes (cs), “Challenger" Expedition 1873 - 76, St. 149 C, Balfour Bay, Royal Sound, Kerguelen Archipelago, 20–60 fathoms. BMNH 1885. 12.1. 86, 10 syntypes, “Challenger" Expedition 1873 - 76, St. 149 B, off Kerguelen Islands, Accessible Bay, 49 ° 8 'S 70 ° 12 'E, 20 fathoms, volcanic mud. BMNH 1885. 12.1. 90, 2 syntypes, “Challenger" Expedition 1873 - 76, off Royal Sound, Kerguelen Archipelago, 25 fathoms.
Lagisca laevis Hartmann-Schröder, 1962: ZMH V- 15343, holotype, (cs), 12 July 1958, Puerto Lagunas, Isla Melchor, South Chile, on top of Macrocystis pyrifera, leg. Stuardo.
Harmothoe (Eunoa) truncata Moore, 1902: ANSP 268, holotype (af), locality originally given as "Peary Rel. Exp. 2 August 1892, McCormick Bay" later corrected by Moore (1908) to Icy Cape, Alaska, B. Sharp (collector).
Harmothoe (Eunoa) anderssoni Bergström, 1916: SMNH Type- 586 (2821), 3 syntypes (one of them damaged, indeterminable), Swedish South Polar Expedition 1901–1903, St. 34, 5 June 1902, South Georgia, mouth of Cumberland Bay, 54 ° 11 'S 36 ° 18 'W, 252–310 m, ground temperature + 1,45 °C, grey clay with some stones.
Comparative material examined (see also respective material sections of Adyte hyalina (G. O. Sars, 1873) and Neopolynoe acanellae (Verrill, 1881) below).
Antarctinoe ferox (Baird, 1865): SMF 15166, 1 spm. (cs), “Polarstern” cruise ANT XIII/ 3 / EASIZ I, St. 39 / 0 12 GSN Antarctic, between Vestkap and Halley, 457–459 m, det. R. Barnich and G. Micaletto.
Hermadion africanus (Hartman, 1974): SMF 13611 / 2, 2 spms. (af), “Meteor” cruise 5 / 2 (MINDIK), St. 194, beamtrawl, 28 February 1987, Red Sea, 537–681 m, det. T. Wehe; SMF 13612 / 2, 2 spms. (2 af, 1 mf), “Meteor” cruise 5 / 2 (MINDIK), St. 84 beamtrawl, 7 February 1987, Red Sea, 880–884 m, det. T. Wehe; SMF 13614 / 2, 2 spms. (2 af, 1 mf), “Meteor” cruise 5 (MINDIK) St. 197 beamtrawl, 1 March 1987, Red Sea, 747– 778 m, det. T. Wehe.
Hermadion magalhaensi Kinberg, 1856: SMF 1689 / 1, 1 spm. (cs), Deutsche Tiefsee Expedition 1898 – 99, "Valdivia", St. 160, Kerguelen, Gazelle-Basin, 25 December 1898, det. Ehlers (see Ehlers 1908); SMF 1758 / 1, 1 spm. (cs), Deutsche Tiefsee Expedition 1898 - 99, "Valdivia", St. 160, Kerguelen, Gazelle-Basin, 25 December 1898; det. Ehlers (see Ehlers 1908).
Subadyte pellucida (Ehlers, 1864): SMF 10467 / 1, 1 spm. (cs), 10 September 1997, Banyuls-sur-Mer, près du Laboratoire Arago, in Posidonia beds, 10 m, leg. D. Fiege and R. Barnich, det. R. Barnich.
Description (based on complete syntype of Hermadion magalhaensi for number of segments and prostomium and on elytra and parapodia free in vial).
Body with 48 segments, mid-dorsum and tail uncovered by elytra. At anterior end (Fig. 1 A) prostomium bilobed, without cephalic peaks; ceratophore of median antenna in anterior notch, styles of antennae missing; lateral antennae inserted ventrally to median antenna; anterior pair of eyes situated anterolaterally near anterior corners of prostomium, posterior pair dorsally near hind margin of prostomium; palps tapering.
First or tentacular segment with a pair of tentaculophores inserted laterally to prostomium, each with a notochaeta and a dorsal and a ventral tentacular cirrus, styles missing. Second or buccal segment with first pair of elytra, biramous parapodia and long ventral or buccal cirri abruptly tapering subdistally. Following segments with shorter ventral cirri.
Fifteen pairs of rounded to oval elytra, leaving mid-dorsum and short tail uncovered, on segments 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 26, 29 and 32; last 16 segments cirrigerous; elytral margin without papillae; elytral surface with conical, blunt microtubercles and a few scattered papillae (Fig. 1 B,C). Cirrigerous segments with distinct dorsal tubercles, dorsal cirri with cylindrical cirrophore and long papillate style, slightly exceeding the length of notochaetae, abruptly tapering subdistally.
Parapodia biramous; notopodia and neuropodia with elongate acicular lobe, neuropodia without supraacicular process; tips of noto- and neuroacicula penetrating epidermis (Fig. 1 D). Notochaetae stouter than neurochaetae, short and long notochaetae with numerous rows of short spines and blunt tip (Fig. 1 E); neurochaetae more numerous with distinct rows of spines only distally; tips slightly falcate, unidentate (Fig. 1 F).
Measurements. Syntypes of Hermadion magalhaensi: cs, L 52 mm, W 10 mm for 48 segments (Fig. 1 A); af, L 28 mm, W 5 mm for 35 segments; af, L 46 mm, W 9 mm for 45 segments (only few posterior segments missing, body wall opened ventrally); af, L 13 mm, W 5 mm for 23 segments (bad condition).
Remarks. The genus Hermadion was erected by Kinberg (1856) for H. magalhaensi and H. longicirratus. Regarding the differentiation of both species Kinberg (1856) stated, that H. magalhaensi has smooth prostomial appendages, cirri, elytra, and notochaetae, while these are papillate, respectively serrated (i.e. with rows of spines) in H. longicirratus.
Ehlers (1897) synonymized Hermadion kerguelensis McIntosh, 1885 with H. magalhaensi and questioned the validity of H. longicirratus. Bergström (1916) finally checked Kinberg's type material and found no significant differences between H. magalhaensi and H. longicirratus. According to him the differences observed by Kinberg were due to the rather bad condition of the respective type specimens. Furthermore, Bergström attributed Hermadion to Harmothoe since he considered the generic differences insufficient. Augener (1932) agreed with Bergström regarding the synonymy of Kinberg's species, but he considered Hermadion a valid genus. As we showed above Hermadion differs mainly from Harmothoe due to its lack of cephalic peaks and neuropodial supra-acicular process, but also due to its mid-dorsum which is uncovered by elytra in large specimens, and its exclusively unidentate neurochaetae.
Orensanz (1974) was the first to realize that Lagisca laevis Hartmann-Schröder, 1962 belongs to the genus Hermadion, but without checking its synonymy. Our comparison of the type material of L. laevis and H. magalhaensi clearly showed that this species is also a junior synonym of H. magalhaensi.
Distribution and habitat. South Atlantic/Pacific (Magellan Region), Southern Indian Ocean (Kerguelen Islands); in shallow waters, down to 110 m, on various substrates such as stones, mud, and algae.