Polycirrus bicrinalis 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 : 26-29

Polycirrus bicrinalis Hutchings & Glasby, 1986

Fig. 10a–f , Table 1

Polycirrus bicrinalis Hutchings & Glasby, 1986: 333–334 , figs 6a–f, 12D.

Type locality. Lizard Island , Great Barrier Reef, Australia .

Material examined. HOLOTYPE: AM W199637 , Australia, Lizard Island , 14º40′ S, 141º 28′ E, in amongst dead coral substrate.

Description. Holotype pale yellow in colour, 5.1 mm long and 0.5 mm wide excluding buccal tentacles, complete with about 72 segments. Sex unknown.

Dorsum faintly tessellated anteriorly. Venter with mid-ventral groove from segment 3, with prominent papilla-like shields until chaetigers 7 or 8 ( Fig. 10a ); with poorly defined ventro-lateral pads, pads deeply incised with many small corrugations, appearing papillated.

Buccal tentacles of three types (most are missing): (1) leaf-shaped, deeply furrowed, (2) cylindrical, thickened distally, distinctly grooved, and (3) cylindrical, uniformly thin, weakly grooved; all tentacles 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, ridged and grooved, extending posteriorly to segment 3. Achaetous segments visible dorsally but obscured by expanded outer lower lip ventrally ( Fig. 10a ).

Notochaetigerous segments 16, extending to segment 18. Notopodia similar in size throughout, prechaetal lobe low, postchaetal lobe digitiform, longer than prechaetal ( Fig. 10b ). Notochaetae within a chaetiger of two types: smooth, narrowly winged, subdistally slightly expanded, posteriorly same form as those anteriorly; secondary notochaetae in all chaetigers pinnate ( Fig. 10c–d ). Neurochaetae beginning on segment 19, 15–25 uncini per row in mid-posterior segments. Neuropodial tori ridge like, similar along body. Uncini with short neck and straight to convex base (Type 1), teeth above main fang arranged in double transverse series (MF:1:7–9), enlarged median tooth above main fang present, subrostral process present as low protuberance ( Fig. 10e–f ).

Nephridial papillae not visible.

Comments. Hutchings & Glasby (1986) report the following variation in the paratypes: 14–16 notochaetigerous segments, neurochaetae from segment 17–20 ( Table 1 ), and dental formula of uncini MF:1:5–10.

Figures

FIGURE 10. Polycirrus bicrinalis Hutchings & Glasby. a. Ventral view of head end. b. Anterior view of notopodium, chaetiger 2, right side. c, d. Two types of notochaetae from notopodium, chaetiger 2. e. Lateral view of anterior uncinus. f. Frontal views from anterior uncinus. Scales: e, f, c, d=0.01 mm, a=1 mm, b=0.1 mm. (Reproduced with permission from Hutchings & Glasby, 1986; http://www.australianmuseum.net.au/Uploads/Journals/17666/185_complete.pdf.