Polycirrus parvus Hutchings & Glasby, 1986

Glasby, Christopher J. & Hutchings, Pat, 2014, Revision of the taxonomy of Polycirrus Grube, 1850 (Annelida: Terebellida: Polycirridae), Zootaxa 3877 (1), pp. 1-117 : 86-87

Polycirrus parvus Hutchings & Glasby, 1986

Fig. 47a–e , Table 1

Polycirrus parvus Hutchings & Glasby, 1986: 339–341 , figs 9a–e; 12E.

Type locality. Off Port Hedland , Western Australia .

Material examined. HOLOTYPE: AM W199628 , Australia, North West Shelf , off Port Hedland, 20°1ʹ12ʺ S, 116°57ʹ36ʺ E, sandy sediments in 40–80 m.

Description. Holotype incomplete, 5.1 mm long, 0.7 mm wide with 27 segments.

Dorsum anteriorly faintly tessellated. Venter anteriorly with mid-ventral groove and discrete ventro-lateral pads; pads more-or-less smooth with a few weak transverse grooves, extending from segment 3 to 9. Mid-ventral groove from segment 3.

Buccal tentacles of two types (few remaining): (1) cylindrical, thickened distally and distinctly grooved and (2) cylindrical, uniformly thin and weakly grooved, both arising at junction between prostomium and upper lip. Prostomial ridge slightly curved, not extending laterally. Upper lip prominent medial lobe with slight lateral expansions at base, margin of medial lobe straight; oral surface glandular, ciliated, with grooves leading to mouth. Inner lower lip oblong; outer region flat, shield-like, oblong, wider than long almost pentagonal in shape, ridged and grooved, extending posteriorly to posterior margin of segment 3. Achaetous segments visible entirely as distinct rings; segment 1 equal in length to segment 2 dorsally ( Fig. 47a ).

Notochaetigerous segments 10, extending to segment 12. Notopodia more-or-less rectangular, short; prechaetal lobe low, postchaetal lobe digitiform, longer than prechaetal ( Fig. 47b ). Notochaetae within a chaetiger consisting of one type, gradually elongating from dorsal to ventral, hirsute, subdistally slightly expanded, posteriorly same form as those anteriorly ( Fig. 47c ). Neurochaetae beginning on segment 14, 15–30 uncini per row. Neuropodial tori erect rectangular pinnules, becoming more erect posteriorly. Uncini with short neck and straight to convex base (Type 1), teeth above main fang arranged in double transverse series (MF:2–5:5–6) enlarged median tooth above main fang present, subrostral process present as low protuberance ( Fig. 47d,e ).

Nephridial papillae not visible.

Comments. Hutchings & Glasby (1986) report the following variation in the paratypes: 9–13 notochaetigerous segments, neurochaetae from segment 12–18, and dental formula of uncini MF:2–6:3–7 ( Table 1 ).

Figures

FIGURE 47. Polycirrus parvus Hutchings & Glasby. a. Ventral view of head end. b. Anterior view of notopodium, chaetiger 4, right side. c. Notochaeta from same. d. Front view of uncinus from mid-posterior body. e. Lateral view of uncinus from midposterior body. Scales a=0.5 mm, b=0.03 mm, c, d, e=0.01 mm) Reproduced with permission from Hutchings & Glasby, 1986; http://www.australianmuseum.net.au/Uploads/Journals/17666/185_complete.pdf).