Syllis nigropunctata Haswell, 1886

Martín, Guillermo San, Álvarez-Campos, Patricia & Hutchings, Pat, 2017, The genus Syllis Savigny in Lamarck, 1818 (Annelida: Syllidae: Syllinae) from Australia (second part): four new species and re-description of twelve previously described species, Zootaxa 4237 (2), pp. 201-243 : 228-229

Syllis nigropunctata Haswell, 1886

Figures 16 D, E, 17, 18

Syllis nigropunctata Haswell, 1886: 744 , pl. 52, figs 1–3.

Typosyllis variegata non Grube, Licher 1999 (in part): 101.

Material examined. AUSTRALIA, NEW SOUTH WALES: 50 m west of Split Solitary Island , St. NSW 677, 30 ° 14' S, 153° 10' 48" E, 1 specimen, AM W.48549, coll . 16 m, Herdmania momus , rocks, sponges and ascidians, 7 March 1992, by P. Hutchings & C. Rose; 50 m west of Split Solitary Island, 30° 14' S, 153° 10' 48" E,. AM W.29505, 5 specimens, coll. 7 Mar 1992 ; north east side of Little Broughton Island, north east of Port Stephens , 32° 37' 5" S, 152° 20' 6" E, AM W.48552, 25 specimens, coll. 11 Mar 2006 ; Golf Course bommie, 500 m north-east of Ulladulla Head , NSW 1298, 35 ° 20' 28" S, 150° 29' 12" E, AM W.48550, 2 specimens, coll . 15 m, 2 May 1997; 150 m east of Burrill Rocks , NSW 1288, 35 ° 23' 24" S, 150° 28' 10" E, AM W29507. 2 specimens, coll. 1 May 1997 ; Fairlight, Port Jackson , NSW 2941, 33 ° 48' S, 151° 17' E, AM W.48551, 2 specimens, coll. 19 Feb 2006 .

Description. Longest complete specimen examined 17 mm long, 1.3 mm wide, with 93 chaetigers. Body long, robust, with a distinct colour pattern; dorsum dark brown, with one distinct unpigmented oval area on laterals, and 2 anterior and 2 posterior irregular areas on each segment; one segment more strongly pigmented alternating with other lighter one ( Figs 16 D, E, 17A), and one additional dark spot on cirrophores ( Fig. 17 A), not present in all specimens; in some specimens all anterior segments are strongly pigmented; from midbody to posterior segments, one transversal, slender line of pigment on each segment, alternating darker and lighter. Prostomium oval; 4 eyes in trapezoidal arrangement. Palps broad, similar in length to prostomium ( Figs 16 D, E, 17A, 18A). Median antenna arising on middle of prostomium, with about 16 articles, longer than combined length of prostomium and palps; lateral antennae shorter than median one, with about 14 articles. Peristomium dorsally reduced, covered by chaetiger 1 ( Figs 17 A, 18A). Dorsal tentacular cirri longer than median antenna, with about 23 articles; ventral tentacular cirri about half as long as dorsal ones, with 10 articles. Dorsal parapodial cirri thick, dark, tapered, with coiled inclusions inside articles, alternating long cirri, longer than body width, with about 32 articles, and short cirri, shorter than body width, with about 18 articles ( Figs 16 D, 17A, 18A); dorsal cirri dorsally coiled over dorsum, more markedly in longer ones ( Figs 16 D, 17A, 18A). Parapodial lobes distinctly bilobed ( Figs 17 A, 18A, C). Ventral parapodial cirri digitiform, shorter than parapodial lobes. Compound chaetae with short bidentate falcigers, blades with proximal tooth slightly smaller or similar in size than distal one, and short to moderate spines on margin; shafts with some short subdistal spines, smooth on posterior segments, especially in ventralmost chaetae, being thicker in more ventral and posterior regions ( Figs 17 B, D, F, 18B–D); antero-posterior and dorsoventral gradation in length of blades, ( Figs 17 B, D, F, 18B-D). Anterior parapodia each with about 18 compound chaetae, with blades 43 µm long above, 33 µm long below ( Figs 17 B, 18B); midbody parapodia with 10 compound chaetae each, blades similar to anterior ones ( Figs 17 D, 18C); posterior parapodia with 8–10 compound chaetae each, blades all similar, distinctly short, 23 µm long above, 21 µm long below ( Figs 17 F, 18D). Dorsal simple chaetae on posterior parapodia only, bidentate, with both teeth similar, and short subdistal spines ( Fig. 17 H). Ventral simple chaetae on posteriormost segments only, smooth, bidentate, with proximal tooth small ( Fig. 17 G). Anterior parapodia with 5–7 slender aciculae each ( Fig. 17 C), becoming progressively fewer in number and larger in size, being only 2 in each midbody parapodium, one thick and distally straight, and the other acuminate ( Fig. 17 E), and finally one solitary acicula in each posterior parapodium, slightly acuminate ( Fig. 17 I). Pharynx extending through about 14 segments; pharyngeal tooth on anterior margin of pharynx. Proventricle through 16–18 segments, with about 45 muscle cell rows (larger specimens; observed after dissection). Pygidium with 2 anal cirri, with 30 articles, and a median stylus.

Remarks. The original types are considered to be lost (AM, pers. com.). Licher (1999) considered this species as a synonymy of S. variegata Grube, 1860 ; both species have an apparently similar marked colour pattern, but they are rather different, with marked differences in grade of pigmentation among alternate segments in some specimens of S. nigropunctata . Moreover the posterior aciculae in S. variegata are large, straight, protruding distinctly from parapodial lobes, instead of being slightly acuminate, not so large nor protruding from parapodial lobes, as in S. nigropunctata . Finally, the compound chaetae are different, although showing some similarities (see San Martín, 2003), having longer spines on margin of blades in S. nigropunctata . So, S. nigropunctata is herein considered as a valid species. Haswell (1886) stated that this species reproduces by means of sexual stolons, but he did not describe the kind of stolon. One of the examined specimens was developing a sexual stolon, but it was not possible to assess which kind.

Habitat. Under stones from intertidal zone to shallow waters.

Distribution. Australia (New South Wales).

Figures

FIGURE 16. Syllis monilaris Savigny in Lamarck, 1818 (AM W. 29492). A, complete specimen. B, midbody, dorsal view. C, posterior end, dorsal view. Syllis nigropunctata Haswell, 1886 (AM W. 29505). D, anterior end, dorsal view. E, prostomium and most anterior segments.

FIGURE 17. Syllis nigropunctata Haswell, 1886 (AM W. 29505). A, anterior end, dorsal view. B, compound chaetae, anterior parapodium. C, aciculae, anterior parapodium. D, compound chaetae, midbody parapodium. E, aciculae, midbody parapodium. F, compound chaetae, posterior parapodium. G, dorsal simple chaeta. H, ventral simple chaeta. I, acicula, posterior parapodium. Scale bars: A: 0.18 mm. B – I: 20 µm.