Polycirrus pumilis Hartmann-Schröder, 1990

Glasby, Christopher J. & Hutchings, Pat, 2014, Revision of the taxonomy of Polycirrus Grube, 1850 (Annelida: Terebellida: Polycirridae), Zootaxa 3877 (1), pp. 1-117 : 94-97

Polycirrus pumilis Hartmann-Schröder, 1990

Fig. 53a–d

Polycirrus pumilis Hartmann-Schröder, 1990: 77 , figs 40–43.

Type locality. South of Yamba , NSW, Australia .

Material examined. PARATYPES: 2, AM W203315 , Australia, New South Wales, Angourie Point, south of Yamba , 29°21' S 154°22' E, 17.i.1976, intertidal .

Description. According to original description, holotype incomplete, 5 mm long, 0.68 mm wide for 27 segments.

Dorsum anteriorly smooth. Venter anteriorly with mid-ventral groove and discrete ventro-lateral pads; pads more-or-less smooth, extending from segment 2 to 8. Mid-ventral groove from segment 3.

Buccal tentacles numerous, of one type, cylindrical, uniformly thin and weakly grooved, some shorter than others, arising at junction between prostomium and upper lip. Prostomial ridge slightly curved, not extending laterally. Upper lip comprising single (medial) lobe only, margin of lobe straight; oral surface glandular, ciliated, with grooves leading to mouth. Inner lower lip oblong, narrow, smooth; outer region flat, shield-like, oblong, wider than long, smooth, extending posteriorly to segment 3. Achaetous segments visible dorsally but obscured by expanded outer lower lip ventrally ( Fig. 53a, b ).

Notochaetigerous segments 10–11, extending to segments 12–13. Notopodia digitiform, short, lobes similar, low and rounded. Notochaetae within a chaetiger consisting of one type, gradually elongating from dorsal to ventral, pinnate, posteriorly same form as those anteriorly ( Fig. 53c ). Neurochaetae beginning on segment 7, 20–24 uncini per row, more in posterior body segments. Uncini with medium length neck and concave base (Type 2, as determined by morphometric study, see below), teeth above main fang arranged in double transverse series (MF:1–3:6–8) subrostral process present as low protuberance ( Fig. 53d ).

Nephridial papillae not visible in paratype.

Comments. According to Hartmann-Schröder (1990), nephridial papillae are present on chaetigers 1–3 of the holotype, that is, segments 3–5. Those on segments 3 and 4 would represent pre-gular membrane nephridial papillae as defined here. The ones on segment 5 would be post-gular membrane nephridial papillae.

The shape of the anteriormost uncini in P. pumilis is not typical of Type 2 as defined by Glasby & Glasby (2006), which has an elongate rostrum, long neck and arched concave base; however, the results of their morphometric analysis utilising all components of shape variation placed these uncini in the Type 2 category. In addition, analysis of co-varying notochaetal characters by these authors provided further support for the grouping of this species with other species bearing Type 2 uncini. Polycirrus pumilis probably belongs to a group of Type 2 species having dimorphic uncini; these species also have early commencement of neuropodia, i.e., prior to segment 10.

Figures

FIGURE 53. Polycirrus pumilis Hartmann-Schröder. a. Head end, dorsal view. b. Head end, ventral view. c. Notochaetae. d. Anterior uncini. Redrawn from Hartmann-Schröder 1990; no scales on original.