Megasyllis inflata ( Marenzeller, 1879 ) 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 : 12-22

Megasyllis inflata ( Marenzeller, 1879) , n. comb.

Figs. 11A–F, 12A–C, 13A–E, 14A–F, 15A–F

Syllis inflata Marenzeller, 1879: 131 , pl. 3, fig. 5.- Izuka 1912: 190, pl. 20, figs 9, 10.- Okuda 1938: 91.- Uschakov & Wu 1962: 58.

Typosyllis inflata Imajima & Hartman 1964: 136 . Eusyllis inflata Imajima 1966a: 99 , figs 32 a–o.

Dentatisyllis inflata Ding, Licher & Westheide 1998: 39 .

Syllis kinbergiana Haswell, 1885: 739 , pl. 51, figs 1–3.

Syllis corruscans (?) Augener 1913: 208. Non Haswell, 1885: 734.

Syllis (Typosyllis) kinbergiana Haswell 1920: 98 , pl. 11, figs 23–27, pl. 12, figs. 1, 2.

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

Material examined. AUSTRALIA, SOUTH AUSTRALIA: Kangaroo Island, Emu Bay , 35° 35'S, 137° 31'E, under rocks, coll. S.J. Edwards, 24 Mar 1977, 4 (3 on SEM stubs), ( AM W14052) ; American River, Maston , old jetty 35° 53'S, 137° 45'E, Zostera sievings, coll. P.A. Hutchings, 2 Mar 1979, 1 ( AM W28214) ; St. Vincent Gulf, Aldinga Reef , under rocks and in roots of marine angiosperms, coll. S.J. Edmonds, 19 Sept 1977, 3 on SEM stubs ( AM W14013) ; Streaky Bay, Speeds Point , 32° 48'S, 134° 13'E, algal washings, coll. P.A .

Hutchings , 14 Mar 1979, 1 ( AM W28211) ; Little Island , 32° 41' S, 132° 10' E, under boulders, coll. P.A. Hutchings, 13 Mar 1979, 2 ( AM W28212) , 3 ( AM W28213) . VICTORIA. Port Phillip Bay, Corio Bay, 38° 08' 36"S, 144° 23' 36"E, clayey sand, 9 m, coll. Marine Science Lab - Corio Bay benthic survey, 9 Feb 1987, 1 ( AM W28228) ; Corio Bay, 38° 05' 49"S, 144° 22' 56"E, silty clay, 11 m, coll. Marine Science Lab - Corio Bay benthic survey, 10 Feb 1987, 2 ( AM W28226) ; Corio Bay, 38° 05' 02"S, 144° 23' 47"E, silty clay, 9 m, coll. Marine Science Lab - Corio Bay benthic survey, 11 Feb 1987, 4 ( AM W28225) ; Corio Bay, 38° 04' 53"S, 144° 23' 23"E, clayey sand, 9 m, coll. Marine Science Lab - Corio Bay benthic survey, 11 Feb 1987, 2 ( AM W28227) . WESTERN AUSTRALIA: Sharks Bay and Champion Bay, 2 (HZM V 7940). NEW SOUTH WALES: Port Jackson , 33° 51'S, 151° 16'E, 1 ( AM W514 ) . QUEENSLAND: Capricorn Group, off North West Island , 23° 18'S, 151° 42'E, coll. G.P. Whitley, Dec 1925, 1 ( AM W28204) .

Description. Body broad, cylindrical, ventrally flattened; 48 mm long, 1.5 mm wide, for 120 segments. Bright orange alive; opaque, yellowish to brown in alcohol. Prostomium short, small, partially hidden under anterior segments ( Figs 11A, 14A–C), oval to pentagonal, with two dorsal lobes or cheeks; 4 small eyes in trapezoidal arrangement; antennae short, median antenna inserted on middle of prostomium, in front of anterior eyes, slightly shorter than combined length of prostomium and palps, lateral antennae inserted on anterior margin, slightly shorter than median antenna ( Figs 11A, 14A–C). Palps large, broad, divergent, basally fused, longer than prostomium ( Fig. 11A), ventrally directed ( Fig. 14B, C). Peristomium similar in length to following segments; segments short, divided into 2–3 rings ( Figs 11A, 14D). Tentacular cirri longer than antennae, dorsal ones slightly shorter than half body width and longer than ventral ones ( Figs 11A, 14B). Antennae, tentacular and dorsal cirri apparently smooth, unarticulated ( Figs 11A, 14A–E) under low magnifications; irregularly articulated, with indistinct articles under high magnifications ( Fig. 11B–D), more marked on smaller specimens. Dorsal cirri arranged alternating long (inserted more dorsally, shorter than half of body width) and short, about half length of long ones ( Figs 11A, 14A–E); dorsal cirri inserted on cirrophores. Parapodial lobes short, rectangular to triangular, with distinct digitiform prechaetal lobe ( Figs 11B–D, 15A). Ventral cirri digitiform, similar in length or slightly shorter than parapodial lobes. Compound falcigers all similar, heterogomph, with thick shafts (with subdistal spines in some cases) and bidentate blades, both teeth similar in size or proximal slightly longer than distal, with short straight spines on margin, except few distal ones, longer, extending beyond proximal tooth. Two kinds of falcigerous chaetae: most dorsal with elongated, slender blades, about 80 µm, 5 on anterior, 3–4 on posterior parapodia, and mid and ventral ones with short and wide blades, about 35 on anterior, 25 on posterior parapodia ( Figs 12A, 13A, 15C), with dorsoventral gradation in length, 61 µm above, and 40 µm below on anterior parapodia; blades strongly bidentate, becoming shorter and wider within fascicle ventrally and on posterior chaetigers ( Figs 12B, 13B, 15D–F). Dorsal capillary chaetae on most posterior parapodia, distinctly slender, bidentate, smooth ( Fig. 13C). Ventral capillary chaetae on posterior parapodia on few specimens, similar to dorsal ones ( Fig. 13D). Anterior aciculae 3–4, with short, slightly oblique tips ( Fig. 12C) reducing to 1–2 ( Fig. 13E), straight, protruding beyond parapodial lobes ( Fig. 15A) on posterior parapodia. Pharynx through 5–6 segments; pharyngeal tooth close to anterior margin ( Fig. 11E), surrounded by crown of about 20 soft papillae ( Fig. 11E, F). Proventricle through 6 segments, with about 43 muscle cell rows ( Fig. 14F). Several specimens with developing male or female Chaetosyllis stolons ( Fig. 15B).

Habitat. Under rocks, among seagrasses, algae, clay and silty clay, from intertidal to 9 m deep.

Distribution. Australia (South Australia, Victoria, Western Australia, New South Wales, Queensland).