Pionosyllis serrata ( Hartmann-Schröder, 1984 )

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 : 346-348

Pionosyllis serrata ( Hartmann-Schröder, 1984)

Figs 72D–F, 75A–N, 76A–F, 77A–F

Eusyllis serrata Hartmann-Schröder, 1984: 18 , figs 23–26.

Material examined. AUSTRALIA: NEW SOUTH WALES: East of Bondi , 33°53.1'S 151°17.4'E, sand, 30 m, Fisheries Research Institute, 24 July 1989, 2 ( AM W24373) ; Bass Point , 34°36'S 150°54'E, 50 m, coll. The Ecology Lab, Ready Mixed Industries, 1 Feb 1990, 3 ( AM W28922) ; Bass Point , 34°36'S 150°54'E, 50 m, coll. The Ecology Lab, Ready Mixed Industries, 1 Feb 1990, 2 on SEM stub ( AM W28913) .

Description. Body fragile ( Fig. 72D), 8.7 mm long, 0.4 mm wide, with 77 chaetigers, pale in alcohol. Prostomium oval, slightly wider than long, with 4 eyes in open trapezoidal arrangement ( Fig. 75A); median antenna more than twice as long as prostomium and palps together, inserted between posterior eyes, near posterior margin of prostomium; lateral antennae shorter than median antenna, similar or slightly longer than combined length of prostomium and palps, inserted near anterior margin; two tufts of cilia posterior to insertion of lateral antennae ( Fig. 72E). Palps long and basally broad, triangular, longer than prostomium ( Figs 72E, 75A), free for almost entire length, basally fused. Peristomium dorsally reduced. Anterior segments with single transverse row of cilia ( Figs 72F, 75A); midbody and posterior segments each with double row of cilia ( Fig. 76A,B). Antennae, tentacular and dorsal cirri long, slender, filiform, smooth, sometimes coiled, of 2 sizes, long and short, long ones distinctly longer than body width, short ones similar in length to half of body width ( Figs 72D,F, 75A, 76A,B). Dorsal tentacular cirri long, ventral ones short. Parapodia of anterior 8–10 chaetigers enlarged, wide, distally truncated ( Fig. 75A) with several small, rounded lobes distally ( Fig. 75M), and numerous, about 12–14 short, broad compound chaetae, with enlarged shafts and short, bidentate blades ( Fig. 76D), about 22–16 µm in length, with few, long, thick spines on margin, distal ones extending beyond proximal tooth ( Figs 75B, 76E). Posterior to proventricle, parapodial lobes becoming conical, slender, with terminal papilla; compound chaetae from proventricle parapodia without enlarged shafts, apparently smooth and distally truncated, and elongated blades with long, thin spines on margin, distally ornamented, distal ones slightly longer than others, extending beyond proximal tooth and sometimes reaching level of distal tooth; most dorsal compound chaetae with more elongate, bidentate blades ( Figs 75C,F,I, 76F, 77A), about 40 µm in length on postproventricle segments, 35 µm on midbody parapodia, 42 µm on posterior parapodia, and several compound chaetae with shorter blades, and dorsoventral gradation in length within fascicle ( Figs 75D,G,J,K, 76F, 77B,C), 13–26 µm on proventricle segments, 16–25 µm on midbody parapodia, 16–37 µm on posterior parapodia; compound chaetae 8–10 on proventricle segments, about 7 on midbody, 4 on posterior parapodia. Blades of posterior chaetae markedly bidentate, both teeth well separated, almost at 90°, and slightly convex ( Figs 75J,K, 77D). Dorsal simple chaetae from midbody, distally weakly bifid ( Fig. 75E), with some spines on margin, becoming thicker posteriorly, with shorter spines on margin ( Figs 75H, 77E). Ventral simple chaetae on posterior parapodia, thick, strongly bidentate, both teeth almost at 90°, proximal tooth slightly hooked, and few, long spines on margin, extending beyond proximal tooth ( Figs 75L, 77F). Aciculae distally knobbed, 3 on anterior parapodia ( Fig. 75M), diminishing progressively along body to 1 ( Fig. 75N). Pharynx through about 6–7 segments; pharyngeal tooth located anteriorly, surrounded by crown of 10 soft papillae and layer of cilia ( Fig. 76C). Proventricle through 7 segments, with 30 muscle cell rows. Two long, filiform anal cirri ( Fig. 72D).

Habitat. Occurring in sandy substrates, from intertidal to about 30 m.

Distribution. Australia (Western Australia, New South Wales).