Odontosyllis detecta Augener, 1913

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 : 286-290

Odontosyllis detecta Augener, 1913

Fig. 22A–C

Odontosyllis detecta Augener, 1913: 236 , pl. III, Fig. 33, textfig. 34; 1927: 153.— Haswell, 1920: 105.— Imajima, 1966: 103, figs 33a–m.— Hartmann-Schröder, 1985: 69.— San Martín, 1990: 613, fig. 16.

Material examined. AUSTRALIA: NEW SOUTH WALES: Port Jackson , 33°51'S 151°16'E, donated by W.A. Haswell, Feb 1920, 1 (slide) ( AM W501 ) .

Description. Only examined specimen, mature, epigamic male, 5 mm long, 0.1 mm wide, with 37 chaetigers, on permanent, stained slide. Adult, non-epigamic specimens from Japan, 6–9 mm long, 1 mm wide, with 40–52 chaetigers ( Imajima, 1966). Specimen from Port Jackson with 2 large, black eyes, small palps and coiled cirri ( Fig. 22A). Occipital flap absent. 4–5 compound chaetae per parapodium, with distally spinose shafts and short, curved, unidentate blades, with short spines on margin ( Fig. 22C). Dorsal simple chaetae from midbody, thin, unidentate, smooth. Ventral simple chaetae absent. Acicula solitary, distally knobbed, with short tip. Pharynx through 2 segments, with 5 teeth and 2 lateral plates. Proventricle through 2 segments ( Fig. 22A). Pygidium semi-circular, with 2 long anal cirri, extending for 6 chaetigers ( Fig. 22B).

Japanese non epigamic specimens (fide Imajima, 1966), with antennae, dorsum and dorsal cirri dark red; with ciliary bands across dorsum, nuchal ridges present; lacking occipital flap. Dorsal cirri alternating in length, shorter than body width, and ventral simple chaetae on posterior parapodia, unidentate, slightly hooked, with short, fine spines on margin.

Remarks. As the only Australian material available for examination was a mature epigamic male, it is difficult to relate this to the non epigamic individuals recorded from Japan by Imajima (1966), but we believe them to represent the same species.

Habitat. Occurring in sand, seagrass, algae; intertidally.

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

Fairy Bower , 33°48.18'S 151°17.4'E, in between large boulders & under small ones, 8 m, coll. P.A Hutchings, 24 Oct 1971, 1 on SEM stub ( AM W24679) ; Grotto Point, Port Jackson , 33°49'S 151°15'E, algae, 4 m, coll. P. Colman, 18 July 1983, 1 ( AM W28915) ; Summer Cloud Bay, Wreck Bay , 35°10.5'S 150°41'E, 15 m, coll. P.A. Hutchings, 29 Nov 1971, 1 ( AM W26325) . WESTERN AUSTRALIA: Off S end of Long Is. Beacon Is. 28°28.8'S 113°46.3'E, dead coral substrate covered in coralline algae, 4.5 m, coll. P.A. Hutchings, 25 May 1994, 2 ( AM W28390) .

Description. Body broad anteriorly, tapered posteriorly ( Fig. 23C), largest complete specimen examined 10 mm long, 0.5 mm wide, with 59 chaetigers, sometimes without colour pattern, but usually with 2–3 dark, dorsal spots on some anterior chaetigers ( Fig. 24A), others dark. Prostomium oval, large, with long cilia laterally ( Fig. 24A); 4 eyes in open trapezoidal arrangement; antennae short, fusiform, shorter than prostomium ( Figs 23D, 24A), median antenna originating between anterior eyes, lateral antennae near anterior margin of prostomium, close to median antennae. Palps small, shorter than prostomium, ventrally folded ( Fig. 24A). Nuchal organs distinct, with long cilia between prostomium and peristomium ( Figs 23D, 24A). Peristomium distinct, similar in length to subsequent segments. Occipital flap covering posterior part of prostomium ( Figs 23D, 24A). Tentacular cirri similar in shape to antennae, but longer. Dorsal cirri fusiform, some more elongated than antennae, those of chaetiger 1 slightly longer than others, shorter than half of body width, slightly longer than parapodial lobes ( Figs 23E, 24C). Parapodial lobes elongated, almost rectangular, distally bilobed ( Figs 23E, 24C); anterior parapodia with distal, digitiform papilla; progressively, posteriorly parapodia becoming more elongated, and distinctly bilobed distally, and distal papilla becoming fused. Ventral cirri digitiform, elongated, reaching or extending beyond parapodial lobes ( Fig. 24C). Compound chaetae slender, with elongated, unidentate blades, with slightly hooked tips ( Figs 23F, 24E,F, 25A), with margins either smooth or with short spines. Anterior parapodia with about 16–18 compound chaetae, with dorsoventral gradation in length of blades within fascicle, 40 µm in length dorsally, 20 µm in length ventrally; number of compound chaetae per parapodium decreasing posteriorly, up to about 9 on posterior parapodia, blades of similar lengths to anterior ones; blades with short, minute subdistal spine ( Fig. 25B–D, arrows). Dorsal and ventral simple chaetae on posterior parapodia, thin, smooth, dorsal ones bifid ( Fig. 24H) and ventral unidentate ( Fig. 24I). Anterior parapodia with 2–3 aciculae, becoming solitary after proventricular segments, distally acuminate ( Fig. 24D,G). Pharynx wide, through 2–3 segments, with 5 teeth and 2 lateral plates. Proventricle wide, short, slightly longer than pharynx ( Fig. 24A), through about 4 segments, with 28–30 muscle cell rows. Pygidium rectangular, small, with 2 lateral, short anal cirri, and 1 median, digitiform papilla ( Fig. 24B).

Habitat. Occurring on algae, bryozoans, dead corals; intertidal and shallow depths.

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

Material examined. AUSTRALIA: WESTERN AUSTRALIA: Cervantes , 30°30'S 115°03'E, fine sand with Posidonia , coll. G. Hartmann-Schröder, 24 Oct 1972, 2 paratypes ( AM W17725) . NEW SOUTH WALES: Halfway Reef, 200 m S of Sullivan Reef, Ulladulla , 35°21'25"S 150°29'19"E, airlift over wall of sponges, Bryozoa, Hydrozoa, 15m, coll. P.B. Berents, K.B. Attwood & A. Murray, 3 May 1997, 1 ( AM W29375) .

Description. Paratype examined 8.1 mm long, 0.8 mm wide, with 43 chaetigers; holotype 10 mm long for 48 chaetigers according to Hartmann-Schröder. Body broad anteriorly, tapering posteriorly, lightly coloured on dorsum of some segments, with 2–4 dark spots ( Fig. 26A). Prostomium oval, about 3 times wider than long; 4 eyes arranged in open trapezoidal pattern, posterior ones covered by occipital flap ( Fig. 26A); antennae short, globular, median antenna slightly longer than lateral ones ( Fig. 26A,B), originating between anterior eyes, lateral antennae inserted on anterior margin of prostomium. Palps small, short. Peristomium dorsally reduced ( Fig. 26A,B). Tentacular cirri globular, similar in size to antennae. Occipital flap oval, covering only posterior margin of prostomium ( Fig. 26A,B). Dorsal cirri globular, sphaerical, shorter than parapodial lobes, those inserted dorsolaterally on chaetigers 1, 4, and 6-8-10-…, slightly larger and more elongate than those on chaetigers 2, 3, 5-7- 9-…, inserted adjacent to parapodial lobes ( Fig. 26B,C). Parapodial lobes elongated, distinctly bilobed distally ( Fig. 26A–C). Ventral cirri short, conical, inserted near distal part of parapodial lobes. Compound chaetae numerous, about 20 on midbody parapodia, with smooth shafts, or provided with minute subdistal spines, and elongate, unidentate blades, distally slightly hooked, provided with short, fine spines on margin ( Fig. 26E), blades of chaetae within fascicle exhibiting dorsoventral gradation in length, about 33 µm in length dorsally, 25 µm in length ventrally. Dorsal and ventral simple chaetae not seen nor previously described.Aciculae solitary, slender, straight. Pharynx wide, short, with 7 teeth (fide Hartmann-Schröder; not seen in material examined) and 2 lateral plates. Proventricle large, 2.5× longer than pharynx ( Fig. 26D), with about 40 muscle cell rows. Pygidium with 2 globular anal cirri, similar to dorsal ones.

Habitat. Occurring on algae and sediment, intertidal.

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