Syllis variegata Grube 1860

Syllis variegata Grube, 1860

Fig. 21

Syllis variegata Grube, 1860: 85, pl. 3, fig. 6.—San Martín 2003: 351, Figs 190, 191.

Typosyllis (Syllis) variegata.— Langerhans, 1879: 532.

Syllis (Typosyllis) variegata.— Augener 1913: 206; 1927: 143.— Haswell 1920: 91, pl. 10, Figs 1, 2.— Fauvel 1923: 262, fig. 97 h–n.

Typosyllis (Typosyllis) variegata.— Hartmann-Schröder 1980: 50; 1981: 27; 1982: 59.

Typosyllis (Typosyllis) cf. variegata.— Hartmann-Schröder 1984: 16.

Typosyllis variegata.— Langerhans 1881: 532.— Day 1967: 248, Figs 12.3 g–i.— Hutchings & Rainer 1979: 752.— Hutchings & Murray 1984: 34.—Campoy 1982: 455, pl. 65.— Licher 1999: 101, fig. 49.

Material examined. AUSTRALIA, NEW SOUTH WALES: NSW 1298, Golf Course bommie, 500 m north-east of Ulladulla Head, 35° 20’ 29” S, 150° 29’ 12” E, coll. 2 May 1997, 15 m, gravel at base of boulders, AM W.53908, 4 specimens. Port Jackson, Middle Harbour, Fairlight, 33° 39’ S, 151° 19’ E, coll. 22 Jul 2005, 0–9 m, AM W.53923, 1 specimen. Port Jackson, Fairlight, 33° 48’ S, 151° 17’ E, coll. 19 Feb 2006, 1 m, balanoid barnacles and sponges, AM W.32040, 3 specimens. MI NSW 3427, north east of Kurnell, “Anchor Reef”, 34° 00’ 33” S, 151° 13’ 51” E, coll. 16 Mar 2009, 17.6 m, coarse-medium shelly sediment with echinoid spines, AM W.53914, 1 specimen.

Diagnosis. Body robust. Transversal reddish ∞ shaped on anterior segments (sometimes indistinct after fixation). Dorsal cirri long, alternating in length in midbody. Compound chaetae bidentate falcigers with short spines on margin. Posterior aciculae straight, distally acute, protruding out from parapodial lobes.

Description. Longest complete specimen 9 mm long, 0.8 mm wide, with 86 chaetigers. Body robust, dark, with a light transverse figure of ∞ on dorsum of each anterior segment, absent after proventricular segments. Prostomium almost circular; four eyes in trapezoidal arrangement and two small anterior eyespots. Palps similar in length to prostomium (Fig. 21A), usually ventrally bent. Median antenna arising between posterior eyes, with about 16 articles, slightly longer than combined length of prostomium and palps; lateral antennae shorter than median one, with about 15 articles. Peristomium shorter than subsequent segments. Dorsal tentacular cirri similar in length to median antenna, with similar number of articles; ventral tentacular cirri about half as long as dorsal ones. Dorsal parapodial cirri of first chaetiger distinctly longer than subsequent ones, with about 29 articles; dorsal parapodial cirri of anterior body chaetigers coiled over dorsum, with about 24 articles (long ones) to 12 articles (short ones); from proventricular segments, dorsal parapodial cirri alternating long, with about 28 articles, and short, with about 17 articles (Fig. 21A). Dorsal cirri dark, with numerous inclusions inside articles. Parapodia distally slightly bilobed. Ventral parapodial cirri digitiform, shorter than parapodial lobes. Compound chaetae with bidentate blades, proximal tooth shorter than distal one, and short spines on margin (Fig. 21B, C, D). Anterior parapodia with 14 compound chaetae each, with blades 40µm long above, 26µm long below (Fig. 21B); midbody parapodia with seven compound chaetae, with blades 37µm long above, 26µm long below (Fig. 21C); posterior parapodia with 5–6 compound chaetae each, with blades shorter, 26µm long above, 20µm long below (Fig. 21D). Dorsal simple chaetae on posterior parapodia only, slightly bidentate (Fig. 21E). Ventral simple chaetae only on far posterior segments, more distinctly bidentate than dorsal one (Fig. 21F). Anterior parapodia with three aciculae each, distally acute, one more slender than others and slightly distally oblique (Fig. 21G), two aciculae in each midbody parapodium, thick and distally straight, one larger than other (Fig. 21H), and one solitary acicula in each posteriormost parapodium, distally acute, extending beyond parapodial lobes (Fig. 21I). Pharynx extending through about 10 segments; pharyngeal tooth on anterior margin of pharynx (Fig. 21A). Proventricle through 12 segments, with about 30 muscle cell rows and a midline. Pygidium with two anal cirri, with 21–23 articles.

Remarks. All the Australian specimens agree fairly well with the descriptions of this species, but differ in some aspects. They seem to be more robust and some of them lack the typical colour pattern, probably because of the type of fixation and length of time in alcohol, and others have the colour pattern not as marked as those found in Mediterranean specimens. Furthermore, the Mediterranean specimens have the posterior aciculae more or less darkly pigmented, which are yellowish in the Australian examined specimens. Syllis variegata is considered as a cosmopolitan species, but seems unlikely; and a revision of worldwide populations S. variegata may reveal several cryptic species. Some species having the same characteristic colour pattern have been described, such as Syllis westheidei San Martín, 1984; Syllis ferrani Alós and San Martín, 1987; and Syllis alosae San Martín, 1992, as well as another species still undescribed from the Philippines (see San Martín 1992, 2003; Alós & San Martín 1987). In the case of the Australian specimens, we did not find sufficient morphological differences to describe as a different species, but we suggest that they may be a different species which needs to be confirmed by molecular studies.

Habitat. Found from intertidal to 18 m in shelly sediment.

Distribution. Apparently Cosmopolitan. May be a suite of cryptic species.