Eusyllis assimilis Marenzeller, 1875

San Martin, G & Hutchings, PA, 2006, Eusyllinae (Polychaeta: Syllidae) from Australia with the Description of a New Genus and Fifteen New Species, Records of the Australian Museum 58, pp. 257-370 : 273-276

Eusyllis assimilis Marenzeller, 1875

Figs 10A–J, 11A–F, 12A–C

Eusyllis assimilis Marenzeller, 1875: 158 , pl. 3, Fig. 2.— Fauvel,

1923: 294, fig. 112a–g.—San Martín, 2003: 114, figs 52, 53.? Eudontosyllis aciculata Knox, 1960: 105 , figs 113–117.

Material examined. AUSTRALIA: NEW SOUTH WALES: SW side of South Solitary Is. 30°12'S 153°16'E, coral rubble, 18 m, coll. R.T. Springthorpe, 24 Jun 1992, 1 ( AM W28942); Taupo Seamount, Tasman Sea, 33°14.21'S 156°10.68'E, rough marl bottom, 133 m, coll. J.K. Lowry & party on RV “Franklin”, 2 May 1989, 2 on SEM stub ( AM W28878); Taupo Seamount, Tasman Sea, 33°16.85'S 156°09.15'E, limestone & sand, 244 m, coll. J.K. Lowry & party on RV “Franklin”, 2 May 1989, 4 on SEM stub ( AM W28879); Taupo Seamount, Tasman Sea, 33°16.85'S 156°09.15'E, limestone & sand bottom, 244 m, coll. J.K. Lowry & party on RV Franklin, 2 May 1989, 17 ( AM W28925). SOUTH AUSTRALIA: Lowly Point, 33°00'S 137°47'E, subtidal, 1 ( AM W26357); 4 km NW of 5th Creek, Port Pirie, Spencer Gulf, 33°12'S 137°55'E, subtidal, Posidonia sp. and Amphibolus spp , 4.6 m, T.J. Ward & party, Mar 1980, 1 ( AM W28234). WESTERN AUSTRALIA: Red Bluff, Kalbarri, 27°42'S 114°09'E, mixed coralline algae on rocky shore, 3.5 m, coll. J.K. Lowry, 10 Jan 1984, several ( AM W28941); Bundegi Reef near Point Murat, Exmouth Gulf, 21°49'S 113°11'E, orange finger sponge, 9 m, coll. J.K. Lowry, 4 Jan 1984, WA-398, 1 ( AM W26738).

Additional material examined. Spain: Off Cabo Cros, Soller, Mallorca, Balearic Is., 39°38.50'N 02°25.13'E, dredged 59–61 m, 6 ( MNCNM 8637 ); Off Ribadeo, Lugo, Galicia, 43°40.59'– 43°40.25'N 7°02.77'– 7°04.35'E, dredged 114–116 m, 8 ( MNCNM 8643 ) .

Description. Material examined small to medium size (10 to <5 mm length), described specimen 5 mm long, 0.54 mm wide, with 41 chaetigers (all incomplete specimens), fragile. Elsewhere; specimens exceeding 40 mm in length reported. Prostomium oval, deeply incised posteriorly, forming 2 distinct lobes, densely ciliated on margin ( Figs 10A, 11A,C); 4 eyes in open trapezoidal arrangement; antennae long, slender, much longer than combined length of prostomium and palps, irregularly pseudoarticulated; lateral antennae inserted near anterior margin of prostomium, median antenna arising slightly posteriorly to lateral ones ( Figs 10A, 11A,C). Palps broad, similar in length to prostomium or slightly longer. Peristomium shorter than subsequent segments; dorsal tentacular cirri long, similar in shape but longer than median antenna, ventral tentacular cirri about quarter length of dorsal ones. Occipital flap Fig.

midbody; (C) remaining compound chaetae, midbody; (D) dorsal simple chaeta; (E) acicula; (F) anterior end of pharynx; (G) parapodium, midbody. A,F: AM W28404; B–G: AM W28408. Scales: A 0.2 mm, B–

E 20 µm, F 0.1 mm, G 0.18 mm.

present ( Fig. 11A,C). Dorsal cirri of chaetiger 1 elongated, longer than dorsal tentacular cirri, also indistinctly articulated; following dorsal cirri irregularly alternating long cirri, slightly longer than half of body width, and others distinctly shorter, all smooth, elongated, tapered ( Figs 10A, 11B). Parapodia with prechaetal lobes. Parapodia dorsally with cilia; other groups of cilia dorsally along body close to dorsal cirri ( Figs 10B, 11B). Ventral cirri triangular, shorter than parapodial lobes ( Fig. 11B). Compound chaetae heterogomph falcigers, with shafts distally covered in numerous, thin spines. Two different types of compound chaetae present, one with slender, bidentate blades, both teeth similar, and short spines on margin ( Figs 10E,I, 12A), located dorsally, others with shorter and larger blades, strongly bidentate, both teeth similar on anterior parapodia ( Figs 10F, 12B), on posterior parapodia proximal tooth becoming longer and stouter, located more ventrally within bundles ( Figs 10J, 12C). Anterior parapodia with 3 compound chaetae of slender type, blades about 20–22 µm in length, and 19–20 compound chaetae of broad type, blades about 15 µm in length. Posteriorly along body, number of compound chaetae decreases, posterior parapodia with 1–2 compound chaetae of slender type, blades 15–22 µm in length, and 6 of broad type, with prominent proximal tooth, and minute spines or smooth on margin, about 16 µm in length. Dorsal simple chaetae slender, capillaries, unidentate, with minute subdistal spines on margin ( Fig. 10H), present only on posterior parapodia. Ventral simple chaetae not seen. Anterior parapodia with 2 slender aciculae, with slightly bent tip ( Fig. 10D); posteriorly single aciculum present, thicker than anterior ones, distally bent and extending beyond parapodial lobes ( Fig. 10G). Pharynx through about 7–8 segments; opening surrounded by a crown of 17–20 soft papillae and dense layer of cilia ( Fig. 11D–F); plus crown of 10 smaller papillae basally ( Fig. 11D); pharyngeal tooth large, located on anterior margin Habitat. Occurring in all kind of substrates, from intertidal to more than 500 m depth.

Distribution. North Atlantic, Mediterranean Sea, North Pacific, New Zealand, Australia (Western Australia, South Australia, New South Wales).