Polycirrus quadratus Hutchings, 1990

Glasby, Christopher J. & Hutchings, Pat, 2014, Revision of the taxonomy of Polycirrus Grube, 1850 (Annelida: Terebellida: Polycirridae), Zootaxa 3877 (1), pp. 1-117 : 99

Polycirrus quadratus Hutchings, 1990

Fig. 55a–e

Polycirrus quadratus Hutchings, 1990 , 384–386, figs 3a–e.

Type locality. Hong Kong .

Material examined. HOLOTYPE: AM W201886 . Hong Kong, Cox Head Rock , 22°15' N 114°15'E, coll. 19.iv.1986, underneath boulders in 2–5 m.

Description. Holotype incomplete, 20 mm long, 1.5 wide with 36 segments.

Dorsum anteriorly tessellated (and inflated). Venter anteriorly with mid-ventral groove and discrete ventrolateral pads; pads incised and tessellated, extending from segment 2 to 13. Mid-ventral groove from segment 3.

Buccal tentacles numerous, of two types: (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, extending laterally along anterodorsal base of upper lip. Upper lip trefoiled, small wing-like lobes laterally, margin of medial lobe convoluted; oral surface glandular, ciliated, with grooves leading to mouth. Inner lower lip oblong, rounded, divided into two equal lobes, ridged; outer region flat, shield-like, oblong, longer than wide, smooth, extending posteriorly to posterior margin of segment 4. Achaetous segments visible dorsally but obscured by expanded outer lower lip ventrally ( Fig. 55a ).

Notochaetigerous segments 12, extending to segment 14. Notopodia digitiform with tips slightly swollen, lobes similar, low and rounded. Notochaetae within a chaetiger consisting of two types, smooth, narrowly winged, uniformly tapered, posteriorly same form as those anteriorly; secondary notochaetae in all chaetigers hirsute, uniformly tapered ( Fig. 55c, d ). Neurochaetae beginning on segment 14. Neuropodial tori erect pinnules, wedgeshaped, becoming more elongate posteriorly, similar along body ( Fig. 55b ). Uncini with long neck and concave base (Type 2), teeth above main fang arranged in single vertical series or arranged in double transverse series (MF:2:1) subrostral process absent ( Fig. 55e ).

Nephridial papillae present, globular pre-gular or cylindrical post-gular. Pre-gular membrane nephridial papillae present on segments 3–4. Post-gular membrane nephridial papillae present, extending from segment 5 to 7; situated at base of notopodia.

Comments. This species exhibits some unusual features including the hirsute secondary notochaetae and the elaborately shaped lower lips.

Figures

FIGURE 55. Polycirrus quadratus Hutchings. a. Anterior ventral view. b. Anterior-mid body, ventral view. c, d. Notochaetae. e. Uncinus, lateral view. Scales a, b=1 mm, c, e, d=0.01 mm. Re-drawn Hutchings, 1990.