Exogone (Parexogone) tasmanica Hartmann-Schröder, 1989

Guillermo San Martin, 2005, Exogoninae (Polychaeta: Syllidae) from Australia With the Description of a New Genus and Twenty-two New Species, Records of the Australian Museum 57, pp. 39-152 : 118-119

Exogone (Parexogone) tasmanica Hartmann-Schröder, 1989

Figs. 69A–D, 70A–H

Exogone obtusa tasmanica Hartmann-Schröder, 1989: 31, figs. 38–43.

Material examined. AUSTRALIA: QUEENSLAND. 1 specimen, AM W26556, Halifax Bay, north of Townsville, 19°9'S 146°37'E, 5 m, Queensland Nickel Pty Ltd, July 1977. 1 specimen,AM W26570, Halifax Bay, north of Townsville, 19°7'S 146°33'E, 2 m, Queensland Nickel Pty Ltd, Jan 1977. 1 specimen, AM W26576, Halifax Bay, north of Townsville, 19°10'S 146°44'E, 5 m, Queensland Nickel Pty Ltd, Jan 1977. NEW SOUTH WALES. 6 specimens, AM W21621, southwest of airport runway extension, Botany Bay, 33°58.33'S 151°10.22'E, 7 m, AM party, 07 Apr 1992. 7 specimens, AM W21622, southwest of airport runway extension, Botany Bay, 33°58.33'S 151°10.22'E, 7 m, AM party, 7 Apr 1992. 4 specimens, AM W22979, Bass Point, 34°36'S 150°54'E, 50 m, The Ecology Lab, for Ready Mixed Industries, 1 Feb 1990. 2 specimens, AM W24369, east of Long Reef, 33°44.72'S 151°22.72'E, sand, 60 m, Fisheries Research Institute (NSW), 23 Jan 1990. 1 specimen, AM W24707, 300 m north east of Green Point, Hawkesbury River, 33°34'S 151°13.5'E,A.R. Jones & A. Murray, 17 May 1982. 6 specimens, AM W26480, 800 m WSW from tip of airport runway extension, Botany Bay, 33°58.33'S 151°10.22'E, 7 m,Australian Museum party, 6 Apr 1992. 1 specimen, AM W26481, south of airport runway extension, northeast Botany Bay, 33°58.13'S 151°11.16'E, 5 m, AM party, 27 July 1992. 2 specimens, AM W26482, 800 m WSW from tip of airport runway extension, Botany Bay, 33°58.33'S 151°10.22'E, 7 m, AM party, 6 Apr 1992. 1 specimen, AM W26483, 800 m WSW from tip of airport runway extension, Botany Bay, 33°58.33'S 151°10.22'E, 7 m, AM party, 6 Apr 1992. 1 specimen, AM W26484, 800 m WSW from tip of airport runway extension, Botany Bay, 33°58.33'S 151°10.22'E, 7 m, AM party, 6 Apr 1992. 1 specimen, AM W26485, 800 m WSW from tip of airport runway extension, Botany Bay, 33°58.33'S 151°10.22'E, 7 m,AM party, 6Apr 1992. 4 specimens, AM W26486, 800 m WSW from tip of airport runway extension, Botany Bay, 33°58.33'S 151°10.22'E, 7 m, AM party, 6 Apr 1992. 4 specimens,AM W26487, 800 m WSW from tip of airport runway extension, Botany Bay, 33°58.33'S 151°10.22'E, 7 m, AM party, 6 Apr 1992. 1 specimen, AM W26488, 800 m WSW from tip of airport runway extension, Botany Bay, 33°58.33'S 151°10.22'E, 7 m, AM party, 6 Apr 1992. 3 specimens, AM W26489, 800–1000 m off Port Botany, east of Botany Bay, 33°58.75'S 151°11.03'E, 7 m, AM party, 6 Apr 1992. 2 specimens, AM W26490, 800–1000 m off Port Botany, east of Botany Bay, 33°58.75'S 151°11.03'E, 7 m, AM party, 6 Apr 1992. 1 specimen, AM W26491, 800–1000 m off Port Botany, east of Botany Bay, 33°58.75'S 151°11.03'E, 7 m, AM party, 6 Apr 1992. 2 specimens, AM W26492, 800–1000 m off Port Botany, east of Botany Bay, 33°58.75'S 151°11.03'E, 7 m, AM party, 6 Apr 1992. 3 specimens, AM W26493, 800–1000 m off Port Botany, east of Botany Bay, 33°58.75'S 151°11.03'E, 7 m, AM party, 6 Apr 1992. 1 specimen, AM W26494, 200–500 m west of airport runway extension, Botany Bay, 33°57.82'S 151°10.43'E, 7 m, AM party, 6 Apr 1992. 2 specimens, AM W26495, 200–500 m west of airport runway extension, Botany Bay, 33°58.28'S 151°11.98'E, 7 m, AM party, 6 Apr 1992. 1 specimen, AM W26496, 200– 500 m west of airport runway extension, Botany Bay, 33°58.28'S 151°11.98'E, 7 m, AM party, 6 Apr 1992. 2 specimens, AM W26497, 200– 500 m west of airport runway extension, Botany Bay, 33°58.28'S 151°11.98'E, 7 m, AM party, 6 Apr 1992. 1 specimen, AM W26498, south of airport runway extension, northeast Botany Bay, 33°58.13'S 151°11.16'E, 5 m, AM party, 6 Apr 1992. 1 specimen, AM W26499, south of airport runway extension, northeast Botany Bay, 33°58.13'S 151°11.16'E, 5 m, AM party, 6 Apr 1992. 2 specimens, AM W27130, near Hungry Beach, Hawkesbury River, 33°34.5'S 151°16.5'E, sandy mud, 4 m, A. Jones & A. Murray, 17 May 1982. 1 specimen, AM W196618, Hawkesbury River, Juno Head-Hungry Beach, 33°34.5'S 151°16.5'E, mud, 4 m, A. Jones & A. Murray, 22 Feb 1980. 1 specimen, AM W196619, between Juno Point & Hungry Beach, Hawkesbury River, 33°34.5'S 151°16.5'E, sandy mud, 12 m A. Jones & C. Short, 05 May 1977. 1 specimen, AM W196620, Juno Head-Hungry Beach, Hawkesbury River, 33°34.5'S 151°16.5'E, sandy mud, middle of river, 10 m, A. Jones & C. Short, 05 May 1977. 2 specimens, AM W196622, Green Pt.–Croppy Pt. Hawkesbury River, 33°33.5'S 151°14.5'E, mud, 6 m, A. Jones & party, 22 Feb 1980. 1 specimen, AM W196623, east end Brooklyn Boat Channel, Hawkesbury River, 33°33'S 151°14'E, A. Jones & party, 16 May 1980. TASMANIA. 16 specimens, AM W27669, near freshwater stream, Parsons Cove, Freycinet National Park, 42°08.6'S 148°16.9'E, clean gravelly sand, intertidal, 0 m, N.W. Riser, 24 Jan 1986. WESTERN AUSTRALIA. 1 specimen, AM W27459, limestone reef, off Ned’s camp, Cape Range National Park, 21°59'S 113°55'E, sponge with epiphytic algae, and muddy worm tubes, 1.5 m, R.T. Springthorpe, 2 Jan 1984.

Description. Body long and slender, filiform (Fig. 69A), 4.8 mm long, 0.2 mm wide, 41 chaetigers. Prostomium ovate, wider than long; 4 eyes in trapezoidal arrangement and, sometimes, 2 anterior eyespots; median antenna inserted close to middle of prostomium, long, cylindrical, slightly longer than combined length of prostomium and palps (Fig. 69B); lateral antennae located near median antenna, in front of line between anterior eyes, much shorter than median antenna (median antenna about 3.3 times longer than lateral antennae), shorter than prostomium (Figs. 69B,C, 70A). Palps broad, longer than prostomium, completely fused along their length, forming a triangular piece (Figs. 69B,C, 70A). Peristomium shorter than following segments; tentacular cirri minute, papilliform (Figs. 69C, 70A). Dorsal cirri similar to tentacular cirri, much smaller than parapodial lobes, absent on chaetiger 2 (Figs. 69B, 70A); parapodial lobes elongate, with a distal papilla.Anterior parapodia each with 1–2 compound chaetae provided with elongate, spiniger-like blades, unidentate or provided with a minute subdistal spine, distally curved, with short marginal spines (Fig. 70B), 30 µm long; in addition 8–9 compound chaetae with short, bidentate falcigers, subdistal tooth small, and short marginal spines (Fig. 70C), all similar in length, about 8 µm long. Decreasing number and length of spiniger-like chaetae posteriorly, only one on midbody segments, lacking on posterior parapodia; posterior parapodia each with 5–6 compound chaetae, with curved blades, moderate marginal spines, with dorsoventral gradation in length (Fig. 70G), 15 µm above, 8 µm below; ventralmost posterior compound chaetae nearly unidentate. Dorsal simple chaetae from anterior parapodia; anterior dorsal simple chaetae slender, provided with a subdistal teeth and short marginal spines (Fig. 70D), becoming progressively thicker, smooth and unidentate posteriorly (Fig. 70F). Ventral simple chaetae on posterior parapodia, sigmoid, smooth, slightly bidentate (Fig. 70H). Acicula solitary, distally expanded and rounded (Fig. 70E). Pharynx through 4–5 segments; pharyngeal tooth on anterior rim (Fig. 70A). Proventricle through 2–3 segments, with about 24 muscle cell rows.

Remarks. Exogone (P.) molesta Banse, 1972 , from the Northeast Pacific is similar, but the antennae are distinctly shorter and the dorsal cirri are longer (Banse, 1972).

Distribution. Australia (Tasmania, New South Wales, Queensland).

Habitat. Sand, mud, from shallow sediments up to 60 m depth.