Pionosyllis kerguelensis ( McIntosh, 1885 )

San Martin, G & Hutchings, PA, 2006, Eusyllinae (Polychaeta: Syllidae) from Australia with the Description of a New Genus and Fifteen New Species, Records of the Australian Museum 58, pp. 257-370 : 337-338

Pionosyllis kerguelensis ( McIntosh, 1885)

Figs 66A–F, 67A–L

Eusyllis kerguelensis McIntosh, 1885 : pl. 29, fig. 4, pl. 33 fig. 3, Pl. 15a fig. 13. Ehlers, 1897: 42; 1913: 473.— Augener, 1924: 376; 1927: 152.— Monro, 1930: 94, fig. 30a-c; 1936: 130.— Knox, 1951: 73; 1960: 105.—Knox & Cameron, 1998: 49, figs 99–100.— Hartman, 1953: 20; 1964: 81, pl. 25, figs 2– 3.— Wesenberg-Lund, 1961: 59, fig. 19.— Hartmann-Schröder, 1965: 115, figs 74; 1986: 77.— Averincev, 1982: 19, pl. II, Figs 1–2.—Hartmann-Schröder & Rosenfeldt, 1988: 39, fig. 16; 1990: 97; 1992: 98.

Pionosyllis comosa Gravier, 1906: 288 .— Ehlers, 1913: 473, pl.32, Figs 1–4.— Benham, 1927: 60.— Monro, 1930: 92; 1936: 128, fig. 20.— Hartman, 1953: 23; 1964: 85, pl. 26 figs 7–8; 1967: 58.

Pionosyllis cosma [sic] Knox, 1960: 106.—Knox & Cameron 1998: 51.

Pionosyllis kerguelensis San Martín & Parapar, 1997: 291 ; San Martín, 2004: 16.

Material examined. KERGUELEN IS. off Christmas harbour, 49°30'S 69°30'W, 200 m, coll. H.M.S. Challenger, presented McIntosh, syntype of Eusyllis kerguelensis, BMNH 1885.12.1.142 (1 ant. end + 2 median parts). FALKLAND ISLANDS: Port Albemarle, 52°11'S 60°26'W, 40 m, sand & algae, coll. Swedish Antarctic Exp. 1901–1903, 8 Sept. 1902, Pionosyllis comosa , 2 ( SMNH 3332, 3728); Burwood bank, 53°45'S 61°10'W, 137–150 m, shell fragments & stones, coll. Swedish Antarctic Exp. 1901–1903, 12 Sept. 1902, P. comosa 1 ( SMNH 3660). ARGENTINA: coast of northern Argentina: 37°15'S 56°8'W, 100 m, sand & gravel, coll. Swedish Antarctic Exped. 1901–1903, 23 Dec 1901, P. comosa 1 ( SMNH 3826). SOUTH GEORGIA: south fjord in front of Nordenskjöld glacier, 54°24'S 36°22'W, 210 m, blue grey mud with few small stones, coll. Swedish Antarctic Exp. 1901–1903, 29 May 1902, Pionosyllis

mm wide for 34 chaetigers; without colour markings (preserved specimens). Prostomium with irregular surface, with longitudinal and transverse grooves forming two posterior cheeks ( Fig. 66A,B); 4 eyes arranged in trapezoidal pattern, anterior pair subequal or smaller than posterior one, located on cheeks and often covered by peristomium and chaetiger 1. Palps broad, long, divergent, distally rounded, slightly longer than prostomium, basally fused, with dorsal furrow ( Fig. 66A,B). Antennae detached or broken in most specimens; much longer than prostomium (according to Hartman, 1964); median antenna more than twice as long as lateral ones (according to Gravier, 1906), originating just in front of median cleft, lateral antennae inserted on anterior margin of prostomium. Peristomium short, dorsally visible, with 2 pairs of tentacular cirri; dorsal tentacular cirri much longer than ventral ones, similar in shape to antennae and dorsal cirri. Long dorsal cirri smooth basally, weakly crenulated distally, about 4 times as long as body width; short dorsal cirri slightly longer than body width, alternating irregularly with long cirri ( Fig. 66B–D). Ventral cirri broad, thick, inflated, almost as large as parapodial lobes on anterior chaetigers ( Fig. 66C,D), except those of chaetigers 1–2 ( Fig. 66F), shorter and thinner posteriorly ( Fig. 66E). Parapodial lobes with long digitiform, dorsal prechaetal papilla ( Figs 66C–E). Anterior parapodia with more than 40 compound chaetae, decreasing to about 10 on posterior parapodia. Compound chaetae heterogomph falcigers; shafts increasing in width posteriorly along body and dorsoventrally within fascicle, with spinose endings. Blades bidentate, with short, distally directed spines on margin; with marked dorsoventral and anteroposterior gradation in both shape and size; dorsal blades on anterior and midbody parapodia long, finely spinulated on margin, distal tooth slightly hooked, proximal tooth slightly smaller, ventral blades basally wider, distal tooth hooked and slightly larger than proximal one ( Fig. 67A–C); posterior segments with 1–2 dorsal chaetae with elongate, slender blades ( Fig. 67D) and remaining chaetae with dorsoventral gradation ( Fig. 67E,F); in midbody, this arrangement more marked ( Fig. 67G–I); on posterior fascicles, most dorsal chaetae with short blades ( Fig. 67J), blades of remaining falcigers similar in length to dorsal ones, but wider, proximal tooth long, triangular ( Fig. 67K). Blades of anterior compound chaetae about 100 µm in length dorsally, 40 µm in length ventrally; posterior blades 55 µm in length dorsally, 35 µm in length ventrally. Anterior parapodia with 4–5 straight, thick, aciculae, pointed tip protruding beyond parapodial lobes; posterior parapodia with 1–2 aciculae ( Fig. 67L). Dorsal and ventral simple chaetae not seen. Pharynx wide, everted in some specimens, extending through 8–9 chaetigers, with 2 crowns of papillae surrounding opening; pharyngeal tooth conical, located on anterior dorsal rim ( Fig. 67A,B). Proventricle barrel shaped, extending to chaetiger 17–18, slightly longer than pharynx.

Habitat. Occurring in fine grey sandy mud, volcanic mud, hard bottom, sand and shells, intertidally to 2916 m ( Ehlers, 1913).

Distribution. Coast of North Argentina, Antarctic and Subantarctic seas: Kerguelen Is. South Georgia, Falkland Is., Magellan area, Davis Sea, Palmer Archipelago, Drake Passage, South Orkney Is. Antarctic Peninsula, South Shetland, Australia (Tasmania, New South Wales), New Zealand, Crozet Is.