Prosphaerosyllis xarifae (Hartmann-Schröder, 1960)

Prosphaerosyllis xarifae (Hartmann-Schröder, 1960) View in CoL

Figs. 15A–F, 16A–F

Sphaerosyllis xarifae Hartmann-Schröder, 1960: 103 , figs. 121– 124; 1979: 103, figs. 139–140; 1980a: 56; 1981: 37; 1984: 25; 1985: 72; 1991: 41. San Martín, 1984a: 236, fig. 54; 2003: 225, figs. 119, 120.

Material examined. AUSTRALIA: QUEENSLAND. 11 specimens, AM W26558, Halifax Bay, north of Townsville, 19°10'S 146°44'E, 5 m, Queensland Nickel Pty Ltd, July 1977. WESTERN AUSTRALIA. 1 specimen, AM W26726, off south end of Long Island, Beacon Island, 28°28.8'S 113°46.3'E, dead coral covered in coralline algae, 5 m, P.A. Hutchings, 25 May 1994. 2 specimens, AM W26727, jetty adjacent to Fisheries Hut, Beacon Island, 28°25.5'S 113°47.0'E, dead plate-coral— Acropora & Montipora spp. , 12 m, P.A. Hutchings, 23 May 1994. 1 specimen, AM W26829, Bush Bay, 30 km south of Carnarvon, 25°10'S 113°39'E, tufted balls of algae on shallow sandflats, 0.5 m, H.E. Stoddart, 6 Jan 1984, WA 417. 2 specimens on SEM stub, AM W27893, inshore reef off Ned’s Camp, Cape Range National Park, 21°59'S 113°59'E, frilly Caulerpa sp. , 1 m, J.K. Lowry, 2 Jan 1984, WA 362.

Description. Body small 3.7 mm long, 0.2 mm wide, 31 chaetigers, broad anteriorly, provided with scattered, small dorsal (Figs. 15A, 16A,B) and ventral papillae; a row of 2– 3 longer papillae on dorsum of each chaetiger from proventricular segments (Figs. 15A, 16C). Prostomium rectangular to oval; 4 large eyes in trapezoidal arrangement, close to each other on each side, and 2 anterior eyespots. Antennae small, pyriform, all similar in shape and size (Figs. 15A, 16B), with bulbous bases and short tip; lateral antennae inserted on anterior margin of prostomium, near eyespots, median antenna inserted between anterior eyes. Palps large, short, totally fused all along their length, with scattered papillae (Figs. 15A, 16B). Peristomium covering dorsally posterior margin of prostomium; tentacular cirri similar in shape to antennae, but smaller (Fig. 15A). Dorsal cirri on all segments; anterior dorsal cirri similar to antennae and tentacular cirri, with bulbous bases and short tip (Figs. 15A, 16B), bases elongate progressively posteriorly and tips become retractile (Figs. 15B, 16C,D); dorsal cirri of midbody slightly longer than parapodial lobes. Parapodial lobes relatively short, conical, with some small papillae (Fig. 16C–E). Compound chaetae heterogomph, with smooth shafts, and unidentate, thin blades, smooth or provided with short marginal spines of dorsal chaetae (Figs. 15D, 16F). Anterior parapodia each with 6 compound chaetae, diminishing to 4 on posterior parapodia. Slight dorsoventral gradation in size of blades, 20–13 µm on anterior parapodia, about 17–16 µm on posterior parapodia. Dorsal simple chaetae from anterior segments, usually from chaetiger 1, unidentate, with few, short subdistal spines (Fig. 15C). Ventral simple chaetae on posterior parapodia, sigmoid, unidentate, smooth (Fig. 15E). Acicula solitary, acuminate (Fig. 15F). Pharynx long and wide, through 4–5 segments; pharyngeal tooth oval, located near middle of pharynx (Fig. 15A). Proventricle similar in length and width to pharynx, through 3–4 segments, with 20–25 muscle cell rows.

Remarks. Prosphaerosyllis campoyi San Martín et al., 1982 is close to P. xarifae, with similar arrangement of dorsal papillae, but the late species has some compound chaetae with blades with long marginal spines (see San Martín, 2003, figs. 100, 101). Prosphaerosyllis riseri Perkins, 1981 has similar dorsal cirri, but the blades of compound chaetae have longer spines on blades and it has only two rows of long dorsal papillae, plus other lateral papillae (Perkins, 1981; Russell, 1991).

Distribution. Red Sea. Mediterranean Sea. Eastern Atlantic, from Bay of Biscay to Canary Islands. Australia (Queensland, Western Australia, South Australia).

Habitat. Intertidal to about 40 m depth, on all kinds of substrates: algae, sand, mud, seagrasses, calcareous substrates.