Sphaerosyllis bifurcata (Hartmann-Schröder, 1979) n.comb.

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 : 90-91

Sphaerosyllis bifurcata (Hartmann-Schröder, 1979) n.comb.

Fig. 45A–I

Parapionosyllis bifurcata Hartmann-Schröder, 1979: 96 , figs. 105–111; 1991: 35.

Material examined. AUSTRALIA: QUEENSLAND.1 specimen on SEM stub, AM W26932, Haughton River estuary, near Cungulla, 19°24'S 147°6'E, tidal flats (mud & sand); mudflat with Avicennia mangroves, S. Dittmann, 5 Sep 1991. NEW SOUTH WALES. 4 specimens,AM W26707, 100 m north west of Julian Rocks, Byron Bay, 28°36.8'S 153°37.8'E, shell and gravel, 15 m, E.L. Albertson et al., 3 Mar 1992.

Description. Body small, slender, 3 mm long, 0.17 mm wide, 32 chaetigers. Anterior segments with few papillae on dorsolateral position (Fig. 45A); from midbody, papillae numerous (Fig. 45B) covering dorsum, few papillae on parapodia; papillae long, distinct, with slender stalk and expanded, rounded or slightly trilobed tips (Fig. 45B), with dark inclusions. Papillae absent on prostomium and palps, scarce on peristomium and anteriormost segments. Prostomium ovate to trapezoidal, wider than long; 4 thick eyes in trapezoidal arrangement. Antennae relatively long, with bulbous bases and long, slender tips, longer than combined length of prostomium and palps (Fig. 45A). Palps similar in length to prostomium, fused all along their length, with distal notch. Peristomium similar in length to following segments, anterior margin slightly bilobed, covering posterior part of prostomium; tentacular cirri relatively long but shorter than antennae. Dorsal cirri relatively long, shorter than tentacular cirri, similar in length to parapodial lobes, with bulbous bases and slender tips (Fig. 45A,B). Parapodial lobes rectangular in dorsal view, provided with 2 distal, rounded papillae (Fig. 45A), and sometimes few other basal papillae similar to dorsal papillae (Fig. 45B). Ventral cirri relatively long, slender. Parapodial glands small, difficult to see, with granular material (Fig. 45A,B). Anterior parapodia each with 6–7 compound chaetae with unidentate blades; shafts thicker ventrally, with a subdistal spur (Fig. 45E); blades of dorsal compound chaetae with long, straight marginal spines, about 16 µm long, blades of ventral compound chaetae smooth, about 12–10 µm long. Number of compound chaetae on each parapodium decreasing posteriorly to 3 on posterior parapodia, with thick shafts provided with strong subdistal spur giving bifurcate appearance, and hooked blades, smooth or provided with short marginal spines (Fig. 45G), about 10 µm long. Dorsal simple chaetae from anterior parapodia, unidentate, with few subdistal marginal spines (Fig. 45F). Ventral simple chaetae on posterior parapodia, sigmoid, distally hooked, unidentate, smooth (Fig. 45H).Anteriormost parapodia each with one slender, straight acicula and another one bent at tip, forming right angle (Fig. 45D); solitary acicula with bent tip, forming right angle in remaining parapodia (Fig. 45I). Pygidium small, with a few rounded papillae and 2 anal cirri, similar to dorsal cirri but slightly thicker (Fig. 45C). Pharynx through 3–4 segments; pharyngeal tooth relatively long, conical, on anterior rim (Fig. 45A). Proventricle through 2 segments, with 15 muscle cell rows.

Remarks. The aciculae were described as distally rounded in the original description; depending upon the view, the aciculae appear to be rounded in some parapodia, but they have the typical shape of Sphaerosyllis in lateral view.

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

Habitat. Mud, fine to coarse sand, gravel. Intertidal to 15 m depth.