Pionosyllis koolalya, San Martin & Hutchings, 2006

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 : 338-340

Pionosyllis koolalya n.sp.

Figs 62A–C, 68A–P, 69A–F

Pionosyllis augeneri .— Hartmann-Schröder, 1991: 359–125. Not Hartmann-Schröder, 1979: 98.

Material examined. HOLOTYPE ( AM W28945) AUSTRALIA: SOUTH AUSTRALIA: Speeds Point, Streaky Bay , 32°48'S 134°13'E, coll. P.A. Hutchings, 14 Mar 1979 . PARATYPE 1 on SEM stub ( AM W28409) . NEW SOUTH WALES: Bottle & Glass Rocks, Port Jackson , 33°51'S 151°16'E, substrate unknown, 12m, coll. G. Clark, 11 Dec 1989 .

Additional material examined. QUEENSLAND: Heron Is., 23°27'S 151°55'E, sand, intertidal, coll. G. Hartmann-Schröder, id. as Pionosyllis augeneri ( HMZ P-21018, P-16796) .

Description. Holotype 12.8 mm long, 0.3 mm wide, with 71 chaetigers; paratype much smaller. Prostomium oval, with 4 eyes arranged in open trapezoidal pattern ( Fig. 68A). Median antenna long, coiled on holotype, several times longer than combined length of prostomium and palps, inserted between posterior eyes; lateral antennae distinctly shorter than median antenna, inserted near anterior margin of prostomium ( Figs 68A, 69A–C). Palps broad, similar in length to prostomium or slightly longer.Tentacular and dorsal cirri long, smooth, coiled on holotype, long on anterior segments, becoming shorter on segments beyond proventricle, alternating long cirri ( Figs 68C, 69A,B), 2–3 times as long as body width, and short cirri ( Fig. 68B), slightly shorter than body width; dorsal cirri with cirrophores. Ciliary bands on dorsum of each segment and areas of dorsal cirri ( Fig. 68B–D), distinct on holotype ( Fig. 68A); anterior segments with single ciliary band ( Fig. 69B,C), double from proventricle segments posteriorly ( Fig. 69D). Parapodial lobes conical, ending with 2 lobes ( Fig. 68B,D). Ventral cirri digitiform, shorter than parapodial lobes anteriorly, becoming longer posteriorly ( Fig. 68B,D).Anterior parapodia with about 10–14 compound chaetae, slightly enlarged, distally truncated shafts, provided with short subdistal spines, and bidentate blades, both teeth similar, with long spines on margin, pointing distally, those of basal part coarse, distal ones thin, reaching or extending beyond proximal tooth, 1–3 slightly longer ( Fig. 68E), rest of chaetae within fascicle with slight dorsoventral gradation in length ( Fig. 68F), 26 µm in length dorsally, 18 µm in length ventrally. Posteriorly, number of compound chaetae per parapodium decreasing, and blades of 1–3 most dorsal compound chaetae becoming proportionally longer ( Figs 68H, 69F) and rest with dorsoventral gradation in length ( Figs 68I, 69E); midbody parapodia with 1–2 compound chaetae with relatively long blades, about 31 µm in length, and 4 compound chaetae 15–25 µm in length; proximal tooth proportionally longer than those of anterior chaetae (Fig. 62A). Posterior parapodia with 1 compound chaeta with long blades ( Fig. 68K), 33 µm long, and 3 compound chaetae, similar to those of midbody, but with distinctly larger proximal tooth ( Figs 68L, 62C), well separated from distal tooth, 18–22 µm in length. Dorsal simple chaetae from midbody, distally bifid to truncate ( Figs 68G, 62B), thicker posteriorly, with short, coarse spines on margin ( Fig. 68 O). Ventral simple chaetae on posterior parapodia, sigmoid, thick, strongly bidentate, both teeth well separated, almost at 90°, proximal tooth long, broad, slightly hooked, with few, long subdistal spines, surpassing level of proximal tooth ( Figs 68P, 62C). Two aciculae on anterior segments ( Fig. 68M), 1 from proventricle segments onwards, distally bilobed ( Fig. 68J), thicker on posterior parapodia ( Fig. 68N). Pharynx through about 6 segments, pharyngeal tooth located on anterior rim. Proventricle through 4 segments, with about 26 muscle cell rows. Pygidium small, with 2 anal cirri.

Remarks. Pionosyllis koolalya is similar to P. serrata described above but differs mainly in lacking enlarged anterior parapodia with thick compound chaetae with markedly short blades; remaining compound chaetae are rather similar, but the dorsal simple chaeta of P. koolalya is truncated, and slightly bifid in P. serrata . All other species of the genus are provided with long, spiniger-like chaetae. These two species also have fewer compound chaetae with distinctly longer blades than other chaetae in the fascicle, but they are relatively short and less than half the length of the longest bladed chaetae. Some material of P. augeneri ( Hartmann-Schröder, 1991) from Heron Island, Queensland, belong to this new species.

Habitat. Unknown, occurring from intertidal to 12 m.

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

Etymology. The specific name comes from an aboriginal word, koolalya , meaning feather epaulettes, in reference to the ciliated dorsum.