Sphaerosyllis goorabantennata, Guillermo San Martin, 2005

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 : 95-96

Sphaerosyllis goorabantennata n.sp.

Fig. 51A–H

Material examined. AUSTRALIA: WESTERN AUSTRALIA. HOLOTYPE: AM W26622, north end of Long Island, Goss Passage, 28°27.9'S 113°46.3'E, dead coral covered in coralline algae & brown algae, 6 m, C. Bryce, 22 May 1994. PARATYPES: 2 specimens, AM W26623, north east entrance to Goss Passage, Beacon Island, 28°27.9'S 113°46.7'E, dead Acropora , coralline & brown algae on coral substrate, 24 m, P.A. Hutchings, 25 May 1994.

Description. Body small, slender, 2.5 mm long, 0.11 mm wide, 26 chaetigers; papillae small, few, those of lateral side longer, especially on chaetiger 2 (Fig. 51A). Prostomium rectangular, wide; 4 small eyes in trapezoidal arrangement. Antennae proportionally long, distinctly longer than combined length of prostomium and palps, with bulbous bases and long, slender, filiform tips (Fig. 51A). Palps blunt, longer than prostomium, fused along their length, with a dorsal furrow and few papillae. Peristomium similar in length to following segments; tentacular cirri long, shorter than antennae. Dorsal cirri similar to those of other species of genus, with a bulbous bases and slender, short tips; shorter than tentacular cirri (Fig. 51A), slightly elongate on posterior parapodia (Fig. 51D). Anterior parapodia each with 5–6 compound chaetae, with unidentate blades, provided with moderate to short marginal spines (Fig. 51C), and dorsoventral gradation in length, 26 µm above, 14 µm below. Posterior parapodia each with 4 compound chaetae, with blades unidentate, provided with short marginal spines, slightly hooked, and slight dorsoventral gradation in length, about 16–12 µm long (Fig. 51F). Dorsal simple chaetae from proventricular segments, unidentate, provided with short marginal spines (Fig. 51E). Ventral simple chaetae on posterior parapodia, sigmoid, smooth, unidentate (Fig. 51G). Acicula solitary, bent at right angle (Fig. 51B,H). Parapodial glands not seen. Pygidium small, with a few small papillae and 2 anal cirri similar to dorsal cirri but longer (Fig. 51D). Pharynx slender, through 3 segments (Fig. 51A). Proventricle through 1–2 segments, with 15 muscle cell rows.

Remarks. Sphaerosyllis goorabantennata n.sp. is characterized by its small size, small scattered papillae, and distinctly long antennae and tentacular cirri, differing from all other species of the genus in these characters. Sphaerosyllis minima Hartmann-Schröder, 1960 and S. minima magnapapillata Hartmann-Schröder, 1974 are also small, but the antennae and tentacular cirri are much shorter, similar to all other species of the genus (Hartmann-Schröder, 1960; 1974a).

Distribution. Australia (Western Australia).

Habitat. In dead corals, 6–24 m depth.

Etymology. From the Aboriginal word gooraba meaning big, in reference to the long antennae, characteristic of the species.