Polycirrus kerguelensis ( McIntosh, 1885 )

Glasby, Christopher J. & Hutchings, Pat, 2014, Revision of the taxonomy of Polycirrus Grube, 1850 (Annelida: Terebellida: Polycirridae), Zootaxa 3877 (1), pp. 1-117 : 63-64

Polycirrus kerguelensis ( McIntosh, 1885)

Fig. 32

Euretho kerguelensis McIntosh, 1885: 474 , pl. 28A, figs 20, 21. (secondary senior homonym of Polycirrus kergulenesis McIntosh, 1885 ).

Type locality. Kerguelen Islands .

Material examined. HOLOTYPE: BMNH 1885 . 12.1.371. St. 149G, Kerguelen Islands , off London River, 48º50ʹ S, 69º18ʹ E, coll. Challenger Expedition, 29.i. 1874, 201 m (110 fm) .

Description. Holotype well preserved with mid-body wall damaged and few chaetae intact, in three pieces representing two individuals, but only one with head. Head-end fragment 20 mm long, 2 mm width for 37 segments, no buccal tentacles remaining. Headless fragments not related to anterior fragment. The following description based on the head-end fragment. Preserved specimen pale cream in colour. Sex unknown.

Dorsum anteriorly tessellated. Venter anteriorly with mid-ventral groove and discrete ventro-lateral pads; pads incised into two by transverse groove), extending from segment 4 to 10. Mid-ventral groove from segment 5 ( Fig. 32 ).

Buccal tentacles missing, arising at junction between prostomium and upper lip. Prostomial ridge distinctly curved, extending laterally along anterodorsal base of upper lip. Upper lip trefoiled with lateral, blindly ending, enclosed diverticulae, margin of medial lobe convoluted; oral surface glandular, ciliated, with grooves leading to mouth. Inner lower lip subtriangular, rounded, ridged and tessellated; outer region flat, shield-like, subtriangular and pointing toward mouth, tessellated, extending posteriorly to posterior margin of segment 3. Achaetous segments visible dorsally but obscured by expanded outer lower lip ventrally ( Fig. 32 ).

Notochaetigerous segments 13, extending to segment 15. Notopodia digitiform, lobes distally flared slightly, postchaetal lobe slightly longer than prechaetal most marked posteriorly). Notochaetae of chaetiger 4 examined; most chaetae damaged (not illustrated here), tips hirsute (tips shorter and less attenuated than those of Polycirrus kerguelensis according to McIntosh), uniformly tapered, wings absent. Neurochaetae beginning on segment 6. Neuropodial tori ridge-like, differ along body, posterior body ones slightly more erect (not illustrated here). Uncini with short neck and straight to convex base (Type 1), teeth above main fang arranged in double transverse series (MF:1:5–6) enlarged median tooth above main fang present, subrostral process present as low rounded protuberance.

Nephridial papillae not visible, although McIntosh describes them as being present on chaetigers 5–7.

Comments. McIntosh (1885) indicates that the material is gravid, however coelomic oocytes are visible only in the posterior fragment, which is not part of the same individual as the anterior fragment. Because some fragments lacked a head we were unsure if all specimens belong to the same species.

Figures

FIGURE 32. Polycirrus kerguelensis (McIntosh). Holotype BMNH 1885.12.1.371. Anterior end, ventral view.