Syllis macrodentata ( Hartmann-Schröder, 1982 ) Hartmann-Schroder, 1982

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 : 219-220

Syllis macrodentata ( Hartmann-Schröder, 1982) , n. comb.

Figures 10 , 11

Typosyllis (Typosyllis) macrodentata Hartmann-Schröder, 1982: 60 , figs 22–25; 1983: 128, figs 4–8; 1984: 15; 1986: 39; 1987: 35; 1989: 21; 1990: 47.

Typosyllis macrodentata . Licher 1999: 96, in part, excluding Typosyllis (Typosyllis) macropectinans Hartmann-Schröder, 1982 .

Material examined. AUSTRALIA, WESTERN AUSTRALIA: Guilderton , 1 Paratype HZM P–16757, coll. in brown algae and Corallina , coll. 26 October 1975, id. G. Hartmann – Schröder ; Denmark, Ocean Beach , HZM P– 17578, 2 specimens, coll. in brown algae, and id. G. Hartmann-Schröder . SOUTH AUSTRALIA: Pondalowie & Marion Bays, Yorke Peninsula, 34° 14.5’ S, 50° E, AM W.45819, 14 specimens; Caulerpa & green algae, 3 m, coll. I. Loch, 22 February 1985, one mounted for SEM, AM W.45818 . NEW SOUTH WALES: Lake Macquarie , HZM P–20023, 1 specimen, in amongst algae, coll. & id. G. Hartmann–Schröder.

Comparative material. Typosyllis (Typosyllis) macropectinans . WESTERN AUSTRALIA, Guilderton, brown algae and Corallina , 26 Oct 1975, holotype , HZM P–16755. Augusta , Saige Bay, 13 November 1975, coll. & id. Hartmann–Schröder, 1 specimen , HZM P–17505. NEW SOUTH WALES. South of Tathra , North Kianinny Gutter, from vertical rock face just above carbonate sand channel, 36° 43' 59" S, 149° 59' 16" E, 10 m depth, Halopteris platycera , 16 March 2004, coll. A.J. Millar, J. Eu & S.J. Keable, AM W.41628, 1 specimen ; North of Batemans Bay , south side of Grasshopper Island, 35° 37' 57" S, 150° 19' 57" E, 16 m depth, Jania natalensis , 14 March 2004, coll. A.J. Millar, J. Eu & S.J. Keable, AM W.41626, 5 specimens ; mouth of Batemans Bay , northwest side of Tollgate Islands, hard platform with occasional rocks and low reefs, 35° 44' 44" S, 150° 15' 31" E, 12 m depth, Halopteris platycera , 13 March 2004, coll. A.J. Millar, J. Eu & S.J. Keable, AM W.41597, 1 specimen .

Description. Longest complete specimen 6 mm long (up to 6.8 mm fide Licher 1999), 0.3 mm wide, with 86 chaetigers. Body relatively short and wide, preserved specimen without colour pattern. Prostomium oval; 4 eyes in trapezoidal arrangement. Palps similar in length to prostomium ( Figs 10 A, 11B). Median antenna arising between the posterior eyes, with about 18 articles, similar in length to combined length of prostomium and palps; lateral antennae shorter than median one, with about 10 articles. Peristomium shorter than subsequent segments ( Figs 10 A, 11A). Dorsal tentacular cirri similar in length to median antenna, with about 17 articles; ventral tentacular cirri with 12–14 articles. Dorsal parapodial cirri shorter than body width, coiled over dorsum ( Fig. 10 A), most anterior ones longer than dorsal tentacular cirri, with about 33 articles (chaetiger 1); alternating long (26–28 articles) and short (20–23) dorsal parapodial cirri; articles with iridescent inclusions inside. Parapodia conical, distally truncated, with a posterior small lobe ( Fig. 10 A). Ventral parapodial cirri digitiform, shorter than parapodial lobes. Compound chaetae with short, triangular, bidentate blades, with proximal tooth smaller than distal one, and long, coarse spines on margin, somewhat curved, with bent tips, similar throughout body ( Figs 10 B– D, 11B). Anterior parapodia with about 10 compound chaetae each, with blades 20 µm long above and 15–16 µm long below ( Fig. 10 B); midbody parapodia with 7–9 compound chaetae each, with blades 20 µm long above and 15 µm long below ( Figs 10 C, 11B); posterior parapodia with 4–7 compound chaetae each, with blades similar in shape and size to midbody ones ( Fig. 10 D). Dorsal simple chaetae on posterior parapodia only (from midbody in small specimens), relatively thick, distally markedly bifid ( Fig. 10 E). Ventral simple chaetae on far posterior segments only, slender, smooth, bidentate with proximal tooth shorter than distal one ( Fig. 10 G). Aciculae slender, distally rounded, slightly oblique, 2–3 in each anterior parapodium, solitary in each posterior parapodium ( Fig. 10 F). Pharynx extending through about 6 segments (somewhat contracted in examined specimens); pharyngeal tooth oval, on anterior margin of pharynx ( Fig. 10 A). Proventricle slender, elongated, through about 6 segments (shorter in small specimens), with about 28–30 muscle cell rows. Pygidium with two anal cirri, with about 20 articles, and a median stylus.

Remarks. The examination of the holotype (HZM P–16755) and of several specimens in the AM identified as Typosyllis (Typosyllis) magnipectinans Hartmann-Schröder, 1982 shows that they are different species. Both species have different colour pattern, being red to orange in T. magnipectinans , with short pharynx, indistinctly articulated dorsal parapodial cirri, and compound chaetae with hooked blades and long, straight spines on margin of blades.

Habitat. Algae in shallow depths.

Distribution. Only reported from Australia (Western Australia, South Australia, New South Wales).

Figures

FIGURE 10. Syllis macrodentata (Hartmann – Schröder, 1982) n. comb. (AM W. 45819). A, anterior end, dorsal view. B, compound chaetae, anterior parapodium. C, compound chaetae, midbody parapodium. D, compound chaetae, posterior parapodium. E, dorsal simple chaetae, in different views. F, posterior acicula. G, ventral simple chaeta. Scale bars: A: 0.18 mm. B – G: 20 µm.

FIGURE 11. SEM of Syllis macrodentata (Hartmann-Schröder, 1982) n. comb. (AM W. 45818). A, anterior end, dorsal view. B, compound chaetae, midbody parapodium.