Parapionosyllis winnunga, 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 : 106-107

Parapionosyllis winnunga n.sp.

Fig. 60A–G

Material examined. AUSTRALIA: QUEENSLAND. HOLOTYPE: AM W26449, Halifax Bay, north of Townsville, 19°09'S 146°37'E, 5 m, Queensland Nickel Pty Ltd, July 1985. PARATYPE: 1 specimen, AM W26450, Halifax Bay, 19°10'S 146°44'E, 5 m, Queensland Nickel Pty Ltd, July 1977.

Description. Body minute, 1.8 mm long, 0.11 mm wide, for 27 chaetigers. Prostomium ovate, wider than long, with 4 large eyes in trapezoidal arrangement and 2 anterior small eyespots, anterior eyes larger than posterior eyes. Antennae slender and proportionally short, spindle-shaped, bowlingpin shaped; median antenna longer than lateral ones, shorter than combined length of prostomium and palps, inserted between posterior eyes; lateral antennae slightly shorter than prostomium, inserted in front of anterior eyes and lateral to eyespots, similar in shape to median antenna. Palps similar in length to prostomium, fused for their basal half (Fig. 60A). Peristomium shorter than following segments; tentacular cirri similar to lateral antennae but shorter. Parapodial glands small, with dark, granular material, usually 2 glands per parapodium. Dorsal cirri similar to lateral antennae (Fig. 60A), slightly longer than parapodial lobes. Ventral cirri digitiform, shorter than parapodial lobes. Compound chaetae similar throughout, but having heterogomph articulation on anterior parapodia (Fig. 60B), and hemigomph articulation with thicker shafts on posterior parapodia (Fig. 60E); blades unidentate, distally rounded, slightly hooked, marginal spines moderate in length, and a subdistal spine near tip, much longer than other spines (Fig. 60B,E). Anterior parapodia each with 7 compound chaetae, 1–2 with long, slender blades about 20 µm long, with moderate, thin marginal spines, and 5 compound chaetae with shorter blades, diminishing progressively in length, 10 µm above, 5 µm below; long blades absent from midbody; posterior parapodia each with 6 compound chaetae, with thicker shafts, dorsoventral gradation in length of blades, 10 µm above, 6 µm below, and short marginal spines. Dorsal simple chaetae from chaetiger 1, unidentate, provided with about 4–5 short serrations, all similar (Fig. 60D), anterior dorsal simple chaetae slender (Fig. 60C). Ventral simple chaetae on each parapodium from about chaetiger 18, sigmoid, smooth and unidentate (Fig. 60F). Solitary acicula on each parapodium, tip enlarged and rounded, slightly hollowed distally (Fig. 60G). Pharynx longer than proventricle, through 3–4 segments; pharyngeal tooth conical, located on anterior margin (Fig. 60A). Proventricle short, through 2–2½ segments, with about 13 muscle cell rows. Pygidium small, bilobed, with 2 long anal cirri, longer than median antenna.

Remarks. Parapionosyllis winnunga n.sp. is characterized by the shape of the blades of compound chaetae, having a relatively long subdistal spine, much longer than present in any other species of the genus.

Distribution. Australia (Queensland, New South Wales).

Habitat. Encrusting algae & ascidians, 16 m depth.

Etymology. The name of the species is derived from the Aboriginal word winnunga, meaning small, minute.