Polycirrus variabilis 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 : 108-109

Polycirrus variabilis Hutchings & Glasby, 1986

Fig. 61a–g , Table 1

Polycirrus variabilis Hutchings & Glasby, 1986: 345–347 , figs 11a–g, 12E.

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

Material examined. HOLOTYPE: AM W199538 Australia, Queensland, Lizard Island , 14°40ʹ S, 145°27ʹ E, in coral substrate 7–12 m.

Description. Holotype complete, 10.6 mm long, 0.8 mm wide with 57 segments.

Dorsum anteriorly smooth, or faintly papillose. Venter anteriorly with mid-ventral groove and poorly defined ventro-lateral pads; pads deeply incised, prominently tesselated. Mid-ventral groove from segment 3.

Buccal tentacles numerous, of two or three types: (1) cylindrical, thickened distally and distinctly grooved and (2) cylindrical, uniformly thin and weakly grooved, some shorter than others, all arising at junction between prostomium and upper lip. Prostomial ridge distinctly curved, not extending laterally. Upper lip comprising single (medial) lobe only, margin of lobe convoluted. Inner lower lip not visible, outer lower lip flat, shield-like, oblong, wider than long, slightly inflated, smooth, extending posteriorly to segment 3. Achaetous segments visible dorsally but obscured by expanded outer lower lip ventrally (Fig. 62a).

Notochaetigerous segments 10–15, extending to segments 12–17. Notopodia digitiform, prechaetal lobe low, postchaetal lobe digitiform, postchaetal lobe slightly longer than prechaetal ( Fig. 61b ). Notochaetae within a chaetiger consisting of one type, gradually elongating from dorsal to ventral, smooth, narrowly winged, appearing faintly striated under oil; damaged ones appear hirsute, uniformly tapered, posteriorly same form as those anteriorly ( Fig. 61c, d ). Neurochaetae beginning on segment 18, 6–22 uncini per row, more present on posterior body neuropodia. Neuropodial tori erect pinnules, rectangular lamellae initially, elongating and becoming broader posteriorly, differ along body. Uncini with short neck and straight to convex base (Type 1), teeth above main fang arranged in double transverse series (MF:1–5:2–6) enlarged median tooth above main fang often present, subrostral process absent ( Fig. 61e–g ).

Nephridial papillae not visible. Pygidium ring with minute ventral papilla.

Comments. Hutchings & Glasby (1986) report the following variation in the paratypes: 10–17 notochaetigerous segments, neurochaetae from segment 15–19 ( Table 1 ).

Summary

In this paper we have revised the genus Polycirrus based on a morphological study of the type material of most of the approximately 74 nominal species; 59 species, including a new species from the Pacific coast of Panama, are accepted as valid. We have provided a standardised illustrated description of most of these valid species. A small minority of nominal species could not be described because the original description is poor and no type material could be found; these 10 species have been designated as species inquirenda (Appendix). Nominal species lacking type material but having a sufficiently detailed original description that could be standardised using the present character set were accepted as valid provided they could be clearly differentiated from other species in the genus. Standardisation will facilitate future descriptions of species of Polycirrus as we are aware that many more remain to be described, including some in Australia and in New Zealand (four new species). However, well-preserved, intact specimens are needed and often they are damaged during collection. This study was based mainly on an examination of type specimens in order to clarify the validity of existing species; we have been unable to fully characterise the morphological limits of each species, apart from synthesing available data on intraspecific variability in the number of notochaetigerous segments and the first appearance of neuropodia. Future taxonomic studies of Polycirrus would be rewarded by a more thorough consideration of morphological variability, as currently we do not have a good understanding of the range of variability that can be accepted for each species. This applies in particular to intraspecific variation of uncini shape within each species and a better understanding of the form and distribution of nephridial papillae in relation to sexual maturity.

Figures

FIGURE 61. Polycirrus variabilis Hutchings & Glasby. a. Ventral view of head end. b. Anterior view of notopodium, chaetiger 6, right side. c, d. Notochaeta from notopodium, chaetiger 6, right side. e. Frontal views of uncini from mid-body. f. Lateral view of uncini from mid-body. g. Lateral view of mid-body uncinus from paratype. Scales a=1 mm, e, f, c, g=0.1 mm, d=0.03 mm, b=0.2 mm. Reproduced with permission from Hutchings and Glasby, 1986; http://www.australianmuseum.net.au/Uploads/ Journals/17666/185_complete.pdf