Syllis hyalina Grube, 1863

Martín, Guillermo San, Lucas, Yolanda & Hutchings, Pat, 2023, The genus Syllis Savigny in Lamarck, 1881 (Annelida: Syllidae: Syllinae) from Australia (Part 3): new species and redescription of previously described species, Zootaxa 5230 (3), pp. 251-295 : 261-264

Syllis hyalina Grube, 1863

Figure 5

Syllis hyalina Grube, 1863: 45 , pl. 4, fig. 8.—San Martín 2003: 426.

Typosyllis hyalina .— Langerhans 1881: 42.—Campoy 1982: 459, fig. 66.— Licher 1999: 199, fig. 86.

Syllis (Typosyllis) hyalina .— Fauvel 1923: 262, Figs 98 a, b.— Day 1967: 246, fig. 12–1 v–x.— Gardiner 1976: 140, fig. 12 v–w.—Day & Hutchings 1984: 277.

Typosyllis (Typosyllis) hyalina .— Hartmann-Schröder 1979: 89, Figs 57–61; 1980: 50; 1981: 26; 1982: 59; 1983: 128; 1984: 15; 1990: 47; 1991: 28.

Material examined. AUSTRALIA, QUEENSLAND: Outer Yonge Reef, Great Barrier Reef , 14° 36’ S, 145° 38’ E, coll. 24 Jan 1977, 30 m, coral rubble, AM W.53889, 1 specimen . NEW SOUTH WALES: MI NSW 8423 , north east of Kurnell , “Anchor Reef”, 34° 00’ 33” S, 151° 13’ 51” E, coll. 16 Mar 2009, 17.8 m, encrusting coralline algae with ascidians, sponges and barnacles, AM W.53891, 2 specimens . NEW SOUTH WALES: MI NSW 8423 , north east of Kurnell , “Anchor Reef”, 34° 00’ 33” S, 151° 13’ 51” E, coll. 16 Mar 2009, 17.8 m, encrusting coralline algae with ascidians, sponges and barnacles, AM W.53891, 2 specimens . Fairlight, Port Jackson , 33.8ºS 151.28ºE, 0.5 m, subtidal brown algae, coll. C. Fraser & M. Capa, 19 Feb 2006, id. with doubts as Syllis zonata by G. San Martín, AM W.37076, 1 midbody fragment . VICTORIA: Rye Pier, Port Phillip Bay , 38° 23’ S, 144° 50’ E, coll. 23 Oct 2005, AM W.53885, 1 specimen . WESTERN AUSTRALIA: Houtman Abrolhos Islands, Goss Passage, south east of Long Island , 28° 28’ 48” S, 113° 46’ 30” E, coll. 22 May 1994, 30 m, dead coral in calcareous substrate. AM W.530901, 2 specimens . WA 517 , Houtman Abrolhos Islands, Beacon Island, Goss Passage , 28° 25’ 30” S, 113° 47’ E, coll. 21 May 1994, AM W.53896, 2 specimens . WA 525 , Houtman Abrolhos Islands, Goss Passage, south east end of Long Island , 28° 28’ 48” S, 113° 46’ 30” E, coll. 22 May 1994, 8 m, dead coral covered in coralline algae, AM W.53895, 1 specimen . WA 528 , Houtman Abrolhos Islands, Goss Passage, Beacon Island , off jetty adjacent to Fisheries Hut , 28° 25’ 30” S, 113° 47’ E, coll. 23 May 1994, 12 m, dead coral, AM W.53884, 1 specimen . WA 511 , Houtman Abrolhos Islands, Beacon Island, Goss Passage , 28° 25’ 30” S, 113° 47’ E, coll. 18 May 1994, 10 m, dead branching coral covered in coralline algae, AM W.53893, 1 specimen . WA 522 , Houtman Abrolhos Islands, north end of Long Island, Goss Passage , 28° 27’ 54” S, 113° 46’18” E, coll. 22 May 1994, 5–6 m, dead coral covered in coralline and brown algae, AM W.53899, 3 specimens . Houtman Abrolhos Islands, west side of Rat Island , 28° 44’ S, 113° 47’ E, coll. 21 Jun 2008, 2 m, dead coral, coll. Aguado & San Martín, 21 Jun 2008, AM W.53902, 1 specimen . WA 539 , Houtman Abrolhos Islands, off south end of Long Island, Beacon Island , 28° 48” S, 113° 46’ 18” E, coll. 25 May 1994, 4–5 m, dead coral covered in coralline algae, AM W.53887, 9 specimens . WA 518 , Houtman Abrolhos Islands, Beacon Island, Goss Passage , 28° 25’ 30” S, 113° 47’ E, coll. 22 May 1994, 8 m, dead coral plates covered in coralline algae, AM W.53919, 5 specimens . WA 528 , Goss Passage, Beacon Island, off jetty adjacent to Fisheries Hut , 28° 25’ 30” S, 113° 47’ E, coll. 23 May 1994, 12 m, dead coral, AM W.53884, 18 specimens . St. 21, Ningaloo Reefs , 22° 17’ S, 118° 48’ E. coll. 19 June 2008, C. Hesse, algal turf, AM W.53905, 1 specimen , AM W.53890, 1 specimen . WA 362 , Cape Range National Park, inshore limestone reefs off Neds Camp , 21° 59’ S, 113° 55’ E, coll. 2 Jan 1984, 1 m, frilly Caulerpa, AM W. 53883, 3 specimens . St. 50, Kimberley region, East Montalivet Island , 15° 06’ S, 125° 18’ E, coll. 15–16 Jul 1988, 0–6 m, some intertidal, AM W.53904, 1 specimen . St. 59, Kimberley region, west side of Cassini Island , 13° 57’ S, 125° 37’ E, coll. 18 Jul 1988, low tide, P Hutchings, AM W.53900, 1 specimen . St. 68, Kimberley region, Lafontaine Island , 14° 10’ S, 125° 47’ E, coll. 19 Jul 1988, 15 m, coll. P. Hutchings, AM W.53902, 3 specimens . WA 392 , Exmouth Gulf, beach at north end of Bundegi Reef , 21° 49’ S, 114° 11’ E, coll. 4 Jan 1984, rocky rubble, brown alga with epiphytic growth, sticky sediment, AM W.53882, 2 specimens . WA 521 , Exmouth Gulf, beach at north end of Bundegi Reef , 21° 49’ S, 114° 11’ E, coll. 4 Jan 1984, rocky rubble, covered in brown alga with epiphytic growth, sticky sediment, AM W.53882, 1 specimen , AM W.53897, 100 specimens . NORTHERN TERRITORY: NT 319 , off Nightcliff, Old Mans Rock , 12° 28’ 30” S, 130° 54’ 12” E, coll. 17 Jul 1993, 5–7 m, coral rubble, sponges and hydroids, AM W.53892, 2 specimens . Darwin Harbour, Dudley Point , 12° 24’ 54” S, 130° 49’ E, coll. 18 Jul 1999, 7–8 m, coral rubble and algae, AM W.53901, 1 specimen . NT 339 , Darwin Harbour, Lee Point , 12° 20’ S, 130° 53’ 48” E, coll. 11 Jul 1993, 3 m, coral rubble, AM W.53894, 2 specimens .

Diagnosis. Body slender. Dorsal cirri short, not thick as in S. armillaris . Compound chaetae of midbody with short, bidentate blades. Midbody aciculae protruding out from parapodial lobes. Posterior aciculae acuminate.

Description. Longest examined specimen 19 mm long, 0.42 mm wide, for 125 chaetigers. Body long and slender, elongated, without colour markings, but some small specimens with single transverse dark brown stripe on some anterior segments. Prostomium pentagonal to oval; four eyes in trapezoidal arrangement. Palps robust, similar in length to prostomium. Median antenna inserted on posterior part of prostomium, between posterior eyes, with 9–10 articles, slightly shorter than combined length of prostomium and palps; lateral antennae shorter than median one, with eight articles each, shorter than median antenna. Peristomium shorter than subsequent segments ( Fig. 5A ). Dorsal tentacular cirri slightly longer than median antenna, with about 15 articles each; ventral tentacular cirri with about nine articles. Dorsal cirri short all along body, shorter than body width, somewhat longer and more slender on anterior segments; dorsal cirri of chaetiger 1 distinctly longer, with 19 articles; and shorter and thicker, more or less fusiform, from midbody onwards ( Fig. 5A ), with well defined cirrophores and articles; from midbody onwards, dorsal cirri alternating short, with about eight articles and slightly longer ones, with about 9–10 articles ( Fig. 5A ). Parapodia conical. Ventral cirri digitiform. All compound chaetae heterogomph falcigers. Anterior parapodia each with about 10–12 chaetae, blades elongated, bidentate, proximal tooth short, and short spines on margin ( Fig. 5B ), blades about 30 μm long above, 15 μm long below; midbody parapodia with 6–7 compound chaetae ( Fig. 5C ), with thick shafts and short bidentate blades, all similar, with short spines on margin, 17–15 μm long; posterior parapodia with 3–4 compound chaetae ( Fig. 5D ), similar to those of anterior parapodia but shorter. Dorsal and ventral simple on far posterior segments of some specimens; dorsal simple chaetae slightly bidentate, with minute spines on margin ( Fig. 5E ); ventral simple chaetae smooth, bidentate ( Fig. 5F ). Anterior parapodia with 3–4 slender aciculae aciculae ( Fig. 5G ), two at midbody ( Fig. 5H ), thick, one distally pointed and other acuminate, slightly protruding from parapodial lobes, and single, acuminate acicula in posterior parapodia ( Fig. 5I ). Pharynx long, extending through about 8–10 segments; pharyngeal tooth on anterior margin of pharynx ( Fig. 5A ). Proventricle similar in length to pharynx, through about 8–10 segments, with 29–30 muscle cell rows. Pygidium triangular, with two articulated anal cirri and one stylus.

Remarks. This species is very similar to Syllis armillaris , above described, and related species (see Remarks of S. armillaris ). Both species have long and slender bodies, without colour pattern (except on some small specimens), with short and relatively thick dorsal cirri, and similar chaetae. However, S. armillaris has thicker dorsal cirri on midbody, with compound chaetae unidentate, and also differs in regard to the aciculae. Both species have been described with pentacerous stolons; however, we have not found any stolons on the Australian material, although several specimens of both species exhibited signs of stolonization. Syllis glandulata Nogueira & San Martín, 2002 , from Brazil, has a similar body and chaetae, but has numerous remarkable refringent glands on lateral margins of each segment ( Nogueira & San Martín, 2002).

Habitat. Common in all littoral and sublittoral substrates, especially on hard bottoms (algae, calcareous algae, dead corals) but also on sand.

Distribution. Apparently Cosmopolitan. Reported all around Australia, but this needs to be confirmed by molecular studies as may represent a species complex.

Figures

FIGURE 5. Syllis hyalina Grube, 1863. AM W.53905. A, anterior end, dorsal view. B, falcigers, anterior parapodium. C, falcigers, midbody parapodium.D, falcigers, posterior parapodium.E, dorsal simple chaeta. F, ventral simple chaeta. G, aciculae, anterior parapodium. H, aciculae, midbody parapodium. I, acicula, posterior parapodium. Scale. A: 0.2 mm. B–I: 20 µm.