Trypanosyllis aeolis Langerhans, 1879

Martín, Guillermo San, Hutchings, Pat & Aguado, María Teresa, 2008, Syllinae (Polychaeta, Syllidae) from Australia. Part. 2. Genera Inermosyllis, Megasyllis n. gen., Opisthosyllis, and Trypanosyllis, Zootaxa 1840, pp. 1-53 : 40-43

Trypanosyllis aeolis Langerhans, 1879

Figs 29C–F, 30A–F, 31A–E

Trypanosyllis aeolis Langerhans, 1879: 558 , figs. 18a, b.-Núñez, San Martín & Brito 1992: 114.-San Martín 2003: 315, figs. 174–176.

Material examined. AUSTRALIA, AUSTRALIAN COMMONWEALTH TERRITORY: ‘ Hole in the Wall’, Jervis Bay , 35° 07' 36"S, 150° 44' 48"E, 12 m, sandy mud, unvegetated sediments, coll. P.A. Hutchings & party, 6 Jun 1989, 1 on SEM stub, ( AM W21041) . NEW SOUTH WALES: Green Point, Jervis Bay , 35° 01'S, 150° 45' 12"E, 12 m, unvegetated sediment, coll. P.A. Hutchings & party, 27 Feb 1990, 1 ( AM W29403) ; East of Broken Bay , 33° 35'S, 151° 41'E, 135 m, coll. FRV "Kapala", 10 Feb 1986, 1 ( AM W28086) .

Description. Body long and wide, dorso-ventrally flattened, ribbon-like ( Figs 29C, 30A), live specimens pale yellow, with brown cirri, some more pigmented than others; preserved specimens colourless. Two segmental rows of minute, spinose dorsal papillae ( Figs 29D, 31B, C). Longest specimen 8 mm long, 1.3 mm wide, 114 chaetigers, plus single stolon, 3.3 mm long, 29 chaetigers. Prostomium oval, almost circular, with two dorsal lobes or cheeks around eyes ( Figs 29D, E, 30A), posteriorly bilobed, and 2 semicircular rows of cilia ( Fig. 29D, E); 4 eyes in trapezoidal arrangement, those on same side, close to each other. Antennae inserted on anterior margin ( Fig. 30A); median antenna longer than combined length of prostomium and palps, with about 22 articles, longer than lateral ones, with 17 articles. Palps short, difficult to see in dorsal view, oval, shorter than prostomium, completely separated. Peristomium dorsally reduced, covered by chaetiger 1; dorsal tentacular cirri similar to antennae, with 25 articles, about twice as long as ventral ones or longer. Dorsal cirri large, thick, shorter than body width, enlarged on middle segments, tapering basally and distally, alternating distinctly longer, thicker, and usually darker, with other shorter and slenderer. Parapodial lobes bilobed. Ventral cirri digitiform, shorter than parapodial lobes. Compound chaetae ( Figs 29F, 30F) numerous, about 15 at midbody, heterogomph, with almost smooth shafts and short blades, distally acute and curved, with proximal tooth minute, and margin with short spines on anterior chaetae, smooth posteriorly, ( Figs 30B, D, 31D, E). Anterior aciculae 2, occasionally 3, straight, acute ( Fig. 30C), protruding beyond parapodial lobes ( Fig. 31A arrow), one larger and longer than other, becoming more similar in size when more posterior ( Fig. 30E). Dorsal and ventral simple chaetae not seen. Pharynx slender and short, through 5–6 segments; trepan with 10 teeth. Proventricle similar in size to pharynx ( Fig. 30A), through 8 segments, with about 30 muscle cell rows. Stolon Tetraglene , male, with dark clusters of spermatozoa.

Remarks. This record of Trypanosyllis aeolis is the first from Australia. The specimens agree with those from the Mediterranean Sea and Canary Islands. The North Pacific T. gemmipara Johnson, 1901 was considered as a synonym of T. aeolis (San Martín, 2003) , but it has longer antennae and dorsal cirri, compound chaetae with distinctly bidentate blades, and produces several simultaneous stolons ( Johnson, 1901), while the single known stolonized specimen of T. aeolis has a solitary stolon. Additional material of T. gemmipara needs to be examined in order to assess the validity of this synonymy. Trypanosyllis gigantea McIntosh, 1885 , from Kerguelen Islands and the Antarctic, has much longer dorsal cirri than T. aeolis and the blades of compound chaetae are unidentate ( McIntosh, 1885) instead of being bidentate. Another species has been recently described from the Eastern Mediterranean having compound chaetae with weakly bidentate blades ( Çinar, 2007), but the dorsal cirri are longer (about 38 articles), the body is proportionally longer and slender, and the blades have slightly longer spines on the margin. A comparative table for all currently known species of Trypanosyllis can be found in Çinar (2007). Another new species is currently being described by Nogueira & Fukuda (2008) from Brazil.

Habitat. Among sediments, algae, sea grasses, calcareous concretions, dead corals, and sponges; intertidal and on shallow waters.

Distribution. North Eastern Atlantic (Madeira, Canary Islands), Mediterranean, Australia (New South Wales).