Syllis pectinans Haswell, 1920

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 : 231-233

Syllis pectinans Haswell, 1920

Figure 19

Syllis (Typosyllis) pectinans Haswell, 1920b: 93 , pl. 10, figs 3-6.

Syllis pectinans . López, et al. 1996: 113, fig. 4; San Martín 2003: 362, figs 196, 197.

Typosyllis pectinans . Hartmann-Schröder 1962: 27, figs. 47-51; 1965: 287; San Martín et al. 1985: 33, figs 7, 8; Licher 1999: 229, fig. 97.

Typosyllis (Typosyllis) lincolnensis Hartmann-Schröder, 1985: 67 , figs 7-10; 1986: 39; 1987: 34; 1989: 20; 1990: 47.

Material examined. AUSTRALIA. NEW SOUTH WALES: Port Jackson , 33° 51’S, 151° 16’E, syntypes AM W 509; Middle Harbour, Fairlight, 33° 48' S, 151° 16' 30" E, AM W.32041, 2 specimens, coll. 6 October 2005 ; Newport, 33° 39' S, 151° 19' E, AM W.32037, 2 specimens, coll. 22 July 2005 ; south Maroubra , 33° 54' S, 151° 12' E, AM W32046, 4 specimens, coll. 5 Feb 2006 . WESTERN AUSTRALIA: Jurien Harbour , 30° 17' 19" S, 115° 2' 39" E, AM W.48556, coll. in algae, intertidal, by Aguado & San Martín, 22 June 2008 .

Comparative material. Typosyllis (Typosyllis) linconlensis . Port Lincoln , Sleaford Bay (South Australia) algae, 3 December 1975, coll. and id. Hartmann-Schröder, 3 paratypes, ZMH P-18377.

Description. Longest complete specimen examined 6 mm long, 0.56 mm wide, with 65 chaetigers; up to 20 mm long when alive and relaxed (fide Haswell 1920b). Fixed specimens contracted, broad, but slender and elongated when alive (fide Haswell 1920b). Some of the examined specimens with a marked colour contrast; anterior part with densely distributed reddish-brown spots, and green-blue-grey pigment after proventricle, probably due to the presence of food particles inside the gut; however, some other specimens lack any colour pattern, others without colour pattern anteriorly but greenish food particles posteriorly and finally others with slender stripes on anterior segments; paratypes of T. (T.) licolnensis Hartmann-Schröder, 1985 without colours marked. Prostomium more or less eliptical; 4 eyes in open trapezoidal arrangement, sometimes also 2 anterior eyespots. Palps similar in length to prostomium ( Fig. 19 A). Median antenna arising in front of anterior eyes, almost on middle of prostomium, with 33–35 articles, slightly longer than combined length of prostomium and palps; lateral antennae shorter than median one, with about 25 articles. Peristomium shorter than subsequent segments ( Fig. 19 A). Dorsal tentacular cirri slightly longer than median antenna, with about 28 articles; ventral tentacular cirri distinctly shorter than dorsal ones, with about 15 articles. Dorsal parapodial cirri elongated, alternating long, similar in length to body width, and short, with 30–32/25–20 articles ( Fig. 19 A), and about 22–17 on mid-posterior segments; anteriormost dorsal parapodial cirri somewhat longer than dorsal tentacular cirri, with up to 36 articles. Parapodia distally bilobed ( Fig. 19 A). Ventral parapodial cirri digitiform. Compound chaetae with blades unidentate, or very slightly bidentate with a minute proximal tooth, somewhat hooked, and long marked spines on margin, diminishing in length from basal to distal region ( Fig. 19 B, D); shafts of posterior chaetae somewhat larger and smooth; blades of compound chaetae on anterior parapodia longer (about 23–22 µm long above, 18–20 µm long below) ( Fig. 19 B) than those of posterior parapodia (about 18–20 µm long above, 15 µm long below) ( Fig. 19 D). Anterior parapodia each with about 7 compound chaetae, posterior parapodia with 6 compound chaetae each. Dorsal simple chaetae on posterior parapodia only, relatively thick, unidentate or with minute proximal tooth and subdistal spines ( Fig. 19 E). Ventral simple chaetae on far posterior segments only, slender, apparently unidentate and smooth ( Fig. 19 G) (or slightly bidentate fide Haswell 1920b). Aciculae distally rounded, apparently hollow on tips ( Figs 19 C, F), 3–4 on each anterior parapodium, solitary on each posterior one ( Fig. 19 F). Pharynx extending through about 8 segments; pharyngeal tooth located on anterior third of pharynx, far away from anterior margin ( Fig. 19 A). Proventricle through about 7–8 segments, with about 35 muscle cell rows. Pygidium with 2 anal cirri, with about 20 articles, and median stylus.

Remarks. Haswell (1920b) stated that this species reproduces by means of sexual stolons, but the kind of stolon was not described.

Habitat. In biogenic concretions (serpulids masses, vermetid reefs, calcareous algae, mussels), and in coarse sand; intertidal and shallow depths.

Distribution. Widely reported through the Pacific Ocean ( Australia, Chile, Panamá) and also in the Iberian Peninsula (Mediterranean and Atlantic coasts). In Australia it was reported in New South Wales, South Australia and Western Australia, but probably it is present all around Australia.

Figures

FIGURE 19. Syllis pectinans Haswell, 1920 (AM W. 32046). A, anterior end, dorsal view. B, compound chaetae, anterior parapodium. C, aciculae, anterior parapodium. D, compound chaetae, posterior parapodium. E, dorsal simple chaeta. F, acicula, posterior parapodium. G, ventral simple chaeta. Scale bars: A: 0.18 mm. B – G: 20 µm.