Syllis lutea ( Hartmann-Schröder, 1960 ), Hartmann-Schroder, 1960

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 : 216-219

Syllis lutea ( Hartmann-Schröder, 1960)

Figure 9

Typosyllis lutea Hartmann-Schröder, 1960: 81 , pl. 2, fig. 38, pl. 5, figs 39–41. Licher 1999: 177, fig. 79. Typosyllis (Typosyllis) lutea . Hartmann-Schröder, 1979: 89, 1981: 27, 1982: 59, 1991: 29. Syllis (Typosyllis) lutea . Ben-Eliahu 1977: 40.

Syllis lutea . Nogueira & San Martín 2002: 75, figs 13–14.

Typosyllis regulata Imajima, 1966: 289 , text-fig. 64 a–n. Day & Hutchings 1979: 104.

Material examined. AUSTRALIA, WESTERN AUSTRALIA: Kimberley site 5, Slate Island , 15° 32' S, 124° 24' E, AM W.29543 , 1 specimen, coll. 9 July 1988, by P. Hutchings; WA 391, Exmouth Gulf, beach at north end of Bundegi Reef, 21° 49' S, 114° 11' E, AM W.48544, 1 specimen, coll. 1–2 m, 4 January 1984, by H. Stoddart; Houtman Abrolhos, Beacon Island, northeast entrance to Goss Passage, 28° 27' 54" S, 113° 46' 42" E, AM W.48537 , 4 specimens, coll. 33 m, 25 May 1994; WA 521, Goss Passage, north end of Long Island, 28° 28' 18" S, 113° 46' 18" E, N end Long Island , AM W.48538 , 4 specimens, coll. 8 m, 22 May 1994; WA 511, Goss Passage, Beacon Island, 28° 25' 30" S, 113° 47' E, AM W.48539 , 5 specimens, coll. 10 m, 18 May 1994; Goss Passage, south east end of Long Island, 28° 28' 48" S, 113° 46' 30" E, AM W.48540 , 2 specimens, coll. 30 m, 22 May 1994; WA 525, Goss Passage, south-east end of Long Island, 28° 28' 48" S, 113° 46' 30" E, AM W.48541 , 4 specimens, coll. 8 m, 22 May 1994; WA 539, off south end of Long Island, Beacon Island , 28° 28' 48" S, 113° 46' 18" E, AM W.48542 , 4 specimens, coll. 4–5 m, 25 May 1994; Houtman Abrolhos, Beacon Island, Goss Passage, 28° 25' 30" S, 113° 47' E, AM W.48543 , 6 specimens, coll. 8 m, 22 May, 1994; WA 522, north end of Long Island, Goss Passage, 28° 27' 54" S, 113° 46' 18" E, AM W.48545 , 8 specimens, coll. 22 May 1994. Whalebone ( Shark Bay ), rocks, 1 m , 16 June 2008, coll. Aguado & San Martín, AM W.48578, 3 specimens; Big Lagoon, Shark Bay , Posidonia , 0–1 m, 17 June, 2008, coll. Aguado & San Martín, AM W.33395, 1 specimen. QUEENSLAND. R.V. Franklin, St. 7, 33° 14’ 21’’ S, 156° 11’ E, AM W.48546 , 2 specimens, coll. by sled in 133 m, May 1989.

Description. Longest complete specimen examined 15 mm long, 0.25 mm wide, with 105 chaetigers. Body long and slender, without colour pattern. Prostomium subpentagonal; 4 eyes in trapezoidal arrangement. Palps slightly longer than prostomium ( Fig. 9 A). Median antenna arising slightly in front of posterior eyes, with 15 articles, similar to combined length of prostomium and palps; lateral antennae slightly shorter than median one, with 11 articles. Peristomium similar in length to subsequent segments ( Fig. 9 A). Dorsal tentacular cirri slightly longer than median antenna, with about 19 articles; ventral tentacular cirri slightly shorter than dorsal ones. Dorsal parapodial cirri whip-shaped ( Fig. 9 A), slender, with distinct coiled, dark, refracting inclusions in most of articles, distinctly alternating long and short; long dorsal parapodial cirri longer than body width, with about 28–20 articles in midbody, short dorsal parapodial cirri in midbody with about 13–14 articles. Ventral parapodial cirri digitiform, sightly elongated anteriorly. Compound chaetae heterogomph falcigers, with bidentate blades with both teeth similar on anterior parapodia ( Fig. 9 A) and becoming gradually unequal, with proximal tooth being larger in more posterior and ventral positions ( Fig. 9 C, D); blades with moderate, thin, curved, distally dressed spines, sometimes reaching level of proximal tooth ( Fig. 9 B–D); blades and shafts being gradually larger from midbody to posterior parapodia ( Fig. 9 C, D). Anterior parapodia each with 1–2 dorsalmost compound chaetae distinctly more slender and longer than remaining ones, with blades 40 µm long, and 6–8 compound chaetae with dorso-ventral gradation in length, 35 µm long above, 17 µm long below ( Fig. 9 B); midbody parapodia with 5–6 compound chaetae each, blades 40 µm long above, 20 µm long below ( Fig. 9 C); posterior parapodia with 5–6 compound chaetae, with blades 30 µm long above, 20 µm long below ( Fig. 9 D). Dorsal simple chaetae only on posterior parapodia, bidentate, with short subdistal spines ( Fig. 9 E). Ventral simple chaetae only on far posterior segments, slender, bidentate ( Fig. 9 F). Aciculae subdistally inflated, acuminate, 2–3 in anterior and midbody parapodia ( Fig. 9 G, H), solitary in posterior parapodia ( Fig. 9 I). Pharynx long, slender, extending through about 9–10 segments; pharyngeal tooth close to anterior margin of pharynx ( Fig. 9 A). Proventricle through 5–6 segments, with about 33 muscle cell rows. Pygidium with 2 anal cirri, with 25 articles each, and median stylus.

Remarks. The species shows some morphological variability; the specimens from Western Australia seem to be smaller and more slender than those from other Australian sites; in some specimens, the long, slender blades of the anterior parapodia can be found up to the midbody and, the short blades with a distinctly larger proximal tooth may appear as soon as from midbody, while the size difference between the teeth can be more marked than in other specimen. Finally, the spines on the margin of the blades can be proportionally longer in some of the specimens.

The wide distribution of the species may be the result of the existence of a complex of species being identified under the same name.

Comparison of material from different areas with molecular techniques may reveal a complex of species.

Habitat. Algae, seaweeds, dead corals, coarse sand, mud. Intertidal to sublittoral.

Distribution. Circumtropical. Red Sea, Japan, Brazil, Cuba. Australia (Western Australia, Queensland).

Figures

FIGURE 9. Syllis lutea (Hartmann-Schröder, 1960) (AM W. 48539). A, anterior end, dorsal view. B, compound chaetae, anterior parapodium. C, compound chaetae, midbody parapodium. D, compound chaetae, posterior parapodium. E, dorsal simple chaeta. F, ventral simple chaeta. G, aciculae, anterior parapodium. H, aciculae, midbody parapodium. I, acicula, posterior parapodium. Scale bars: A: 0.2 mm; B – I: 20 µm.