Megasyllis corruscans ( Haswell, 1885 ) Martín & Hutchings & Aguado, 2008

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 : 6-8

Megasyllis corruscans ( Haswell, 1885) , n. comb.

Figs. 2A–E, 3A–C, 4A–E, 5A–F, 6A–F, 7A–F, 8A–F

Syllis corruscans Haswell, 1885: 734 , pl. 5 0, figs 1–3, pl. 55, fig. 5. Not Augener 1913: 208. — Syllis (Typosyllis) coruscans (sic) Haswell 1920: 99, pl. 11, figs 28–31.

Eusyllis brevicirrata Knox & Cameron, 1971: 25 , figs 11–14. Non Eusyllis brevicirrata Hartmann-Schröder 1985: 67 , figs 11–13; 1986: 41.

Material examined. AUSTRALIA, AUSTRALIAN COMMONWEALTH TERRITORY: Jervis Bay, Darling Road , near anchorages, 35° 07' 18"S, 150° 44' 06"E, 18 m, coll. P.A. Hutchings, 23 Jan 1973, 7 (1 SEM), ( AM W31405) ; Hole in the Wall’ , 35° 07' 36" S, 150° 44' 48" E, sandy mud, unvegetated sediments, 12 m, coll. P.A. Hutchings & party, 6 June 1989, 2 ( AM W21039) . NEW SOUTH WALES: Jervis Bay, off Montagu Roadstead , 35° 02' 12"S, 150° 46'E, unvegetated sediment, 12 m, coll. P.A. Hutchings & party, Feb 1991, 1 ( AM W28230) , 5 Jun 1989, 1 ( AM W21040) ; Port Kembla Outer Harbour , 34° 28' 30"S, 150° 54' 12"E, intertidal, coll. G. Johnstone, 21 May 1995, 1 ( AM W22796) ; Port Jackson, Bottle and Glass Rocks 33° 50' 54"S, 151° 16' 12"E, in sand under rocks at low tide, coll. H. Paxton, 23 Oct 1968, 4 ( AM W4328 ) , 13 (1 SEM) ( AM W4319 ) , 12 m, coll. G. Clark, 11 Dec 1989, 2 ( AM W31403) ; Shark Island , 33° 51' 36"S, 151° 15' 24"E, 2 ( AM W9037 ) ; Grotto Point , 33° 49'S, 151° 15'E, 4 m, algae, coll. P. Colman, 18 July 1983, 1 ( AM W31404) ; Port Jackson , 33° 51'S, 151° 16'E, coll. E.F. Hallmann, Feb 1910, 2 (1 SEM), ( AM W73 ) ; Balmoral Beach , 33° 49' 42"S, 151° 15' 06"E, donated by J.R. Kinghorn, 1909, 2 ( AM W9038 ) ; Long Reef , N of Sydney, 33° 44'S, 151° 19'E, 1 (pharynx and proventricle on SEM stub), ( AM W3224 ) , 12 Feb 1972, 2 ( AM W9041 ) ; Woody Head , 29° 22'S, 153° 22' E, Australian Museum party, 16 Feb 1965, 5 (1 SEM), ( AM W22107) .

Description. Body large reaching up 140 mm long, 5 mm wide, for 150–200 segments (fide Haswell, 1920), cylindrical, ventrally flattened. Longest specimen examined 66 mm long, 4 mm width, 230 segments; yellowish, opaque in alcohol, dark green to dark brown dorsally, light red or orange ventrally, as well as parapodia and cirri; prostomium bright crimson (fide Haswell, 1920). All material examined in this study colourless. Prostomium small, unusually short, more or less hidden under anterior segments ( Fig. 5A–E), oval to pentagonal, with two dorsal lobes or cheeks ( Fig. 2A); 4 small eyes in trapezoidal arrangement; antennae short ( Figs 2A, B, 5A–F, 6A), slightly longer than combined length of prostomium and palps, median antenna inserted between posterior eyes; lateral antennae inserted in front of anterior eyes, slightly shorter than median antenna. Palps large, broad, divergent ( Fig. 2A), fused basally, longer than prostomium, ventrally folded when pharynx not everted ( Fig. 5D). Peristomium similar in length to following segments; segments short, divided in 2–4 rings ( Figs 2A, B, 5A–F, 6A). Tentacular cirri longer than antennae, dorsal ones slightly shorter than body width, and longer than ventral ones ( Figs 2A, 5C–E). Antennae, tentacular and dorsal cirri appear smooth and unarticulated under low magnifications ( Figs 2A, B); irregularly articulated under high magnifications, with indistinct articles ( Figs 2D, E, 5A–F, 6A, E), more distinct on small specimens, becoming less distinct on large specimens. ( Figs 2A, D, E, 5C–F, 6A); dorsal cirri inserted on cirrophores ( Fig. 6A). Parapodial lobes short, triangular, with slightly shorter, distinct prechaetal lobe ( Figs 2D, E, 6A, E). Ventral cirri digitiform, similar in length or slightly shorter than parapodial lobes ( Figs 2A, E, 6A, D, E). Compound falcigers heterogomph, with thick shafts, and subdistal spines, bidentate blades, with both teeth similar, well separated, with short, straight spines on margin, slightly longer when more distal. Falciger compound chaetae of two types: most dorsal with elongate, slender blades ( Figs 3A, 4A, 7D, 8A, D), about 77–80 µm, 2–3, and 3–5 on anterior and posterior parapodia respectively, and most ventral with shorter and larger blades, from 25 to 12 on anterior and posterior parapodia respectively, with dorsoventral gradation in length ( Figs 3B, 4B, 7E, F, 8B, C, E, F), most dorsal from 66 µm to 60 µm and most ventral from 40 µm to 32 µm on anterior and posterior parapodia respectively; blades more strongly bidentate, shorter and wider when more ventral and posterior. Dorsal capillary chaetae typically present on most posterior parapodia, slender, bidentate, with short subdistal spines ( Fig. 4C). Ventral capillary chaetae present on most posterior parapodia of some specimens, larger than dorsal, bidentate, with short subdistal spines ( Fig. 4D). Aciculae 3–4 on anterior parapodia, with short, slightly oblique tips ( Fig. 3C) to 1–2 on posterior parapodia, straight, distally slightly oblique tips ( Fig. 4E). Pharynx through about 10–11 segments; pharyngeal tooth long, dagger-shaped, on anterior margin, surrounded by crown with about 20 soft papillae ( Figs 2A, C, 6B). Proventricle through 9–10 segments, with about 40 muscle cell rows ( Fig. 6C). Several specimens with developing sexual Chaetosyllis stolons ( Figs 6F, 7A) (two palps and 4 eyes, see Potts 1911; San Martín 2003), ventrally, segmented glands on stolons ( Fig. 7B, arrows) with a pore opening on tip of papilla ( Fig. 7B, C).

Remarks. The type material is lost and all the material examined was colourless. Haswell described the species having bright colours; it is presumed that Haswell examined fresh material where colour patterns are conspicuous and that these patterns rapidly disappear after storage in alcohol. The material from Western Australia, described by Augener (1913) (HZM V7940) as Syllis corruscans are in fact Megasyllis inflata (see below).

Habitat. Sediments (sand, mud), algae; intertidal to 18 m.

Distribution. Australia (New South Wales).