Syllis profunda Cognetti, 1955

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 : 279-282

Syllis profunda Cognetti, 1955

Figures 15 , 16

Syllis variegata profunda Cognetti, 1955: 3 , Fig. 2b ; 1957: 20–21, Fig. 4b .

Syllis alternata non Moore, 1908.— San Martín & Viéitez 1984: 153, Figs 1 , 2 .—San Martín 2003: 354, Figs 192, 193.— Çinar & Gambi 2005: 754–755 .— Çinar & Ergen 2003: 777–778, in partim.— Aguado et al. 2008: 20 .

Syllis profunda .— Langeneck et al. 2018: 209 , Fig. 7 .

Typosyllis cf. variegata .— Hartmann-Schröder 1960: 75, Figs 16–20 .

Material examined. AUSTRALIA, NEW SOUTH WALES: NSW 699, 100 m south of Split Solitary Island, 30° 15’ S, 153° 10’ 30” E, coll. 23 June 1992, 16.6 m, hand collected on SCUBA, lace bryozoan, AM W.29503, 7 specimens. North West Solitary Island, Manta Reef, 30° 01’ 30” S, 153° 16’ 30” E, coll. 25 June 1992, 19 m, hand collected on SCUBA, lace bryozoan, AM W.29510, 7 specimens. Elizabeth Reef, reef flat near “Yoshin Maru Iwaki” wreck, 29° 55’ 48” S, 159° 01’ 18” E, coll. 14 Dec 1987, intertidal, small heads of Acropora valida , Pocillopora damicornis, AM W. 53819, 1 specimen. Bass Point, 34° 36’ S, 150° 54’ E, coll. 03 Jan 1991, 40 m, Smith-McIntyre Grab, AM W.29516, 1 specimen. NSW 1336, Northern side of Bannister Head, 35° 19’ 09” S, 150° 29’ 07” E, coll. 6 May 1997, 18 m, hand collected on SCUBA, grey sponge from top of boulder, AM W.53821. WESTERN AUSTRALIA: WA 222, Houtman Abrolhos Islands, Goss Passage, north end of Long Island, 28° 28’ 18” S, 113° 46’ 18” E, coll. 22 May 1994, 8 m, hand collected on SCUBA, dead coral covered in coralline and brown algae, AM W.53826, 5 specimens. WA 523, Houtman Abrolhos Islands, north end of Long Island, Goss Passage, 28° 27’ 54” S, 113° 46’ 18” E, coll. 22 May 1994, 8 m, hand collected on SCUBA, dead coral covered in coralline algae, AM W.53824, 1 specimen. WA 521, Houtman Abrolhos Islands, Goss Passage, north end of Long Island, 28° 28’ 18” S, 113° 46’ 18” E, coll. 22 May 1994, 8 m, hand collected on SCUBA, dead coral covered in coralline algae, AM W.53822, 1 specimen. WA 528, Houtman Abrolhos Islands, Goss Passage, Beacon Island of jetty adjacent to Fisheries Hut, coll. 12 m, 23 Jun 1994, AM W.53815, 3 specimens. WA 518, Houtman Abrolhos Islands, Beacon Island, Goss Passage, 28° 25’ 30” S, 113° 47’E, coll. 22 May 1994, 8 m, hand collected by SCUBA, dead coral covered in coralline algae, AM W.53817, 6 specimens. St.101, Kimberley region, south-west corner of Lucas Island, 15° 13’S, 124° 31’E, coll. 24 July 1988, 30 m, hand collected of SCUBA, AM W.53818, 3 specimens. St. 54, Kimberley region, Condillac Island, 14° 06’ S, 125° 33’ E, coll. 16 Jul 1988, coll. P. Hutchings, AM W.53820, 1 specimen. Site 50, Kimberley region, East Montalivet Island, 15° 06’ S, 125° 18’ E, coll. 15 July 1988, intertidal, AM W.53816, 1 specimen. NORTHERN TERRITORY: NT 319, Darwin Harbour, Dudej Point, 12° 24’ 54” S, 130° 49’E, coll. 18 July 1993, 8 m, collected on SCUBA, coral rubble & algae, AM W.53823, 1 specimen.

Diagnosis. Body of very large size. Antennae, tentacular and dorsal cirri very long, slender. Compound chaetae bidentate falcigers, with short spines on margin of blades. Posterior aciculae straight, protruding out from parapodial lobes. Pharynx and proventricle long.

Description. Large, pale, colourless species. Body long and relatively slender, with long to very long, slender dorsal cirri. Longest complete specimen, 21 mm long, 1.35 mm wide, with 145 chaetigers; average size specimen, 14 mm long, 1 mm wide, for 117 chaetigers. Prostomium semicircular, with two pairs of eyes in trapezoidal arrangement ( Fig. 15A ). Median antenna long, distinctly longer than combined length of prostomium and palps together, inserted between posterior eyes, with about 44 articles; lateral antennae inserted in front of anterior eyes, with 28–30 articles. Palps broad, triangular, slightly longer than prostomium, fused at base, with distinct median groove. Peristomium much shorter than subsequent segments, dorsally covered by first chaetiger, with two pairs of tentacular cirri ( Fig. 15A ). Dorsal tentacular cirri slightly longer than lateral antennae, with about 33 articles, ventral ones with 22 articles. Dorsal cirri very long, several times longer than body width; dorsal cirri of first chaetiger very long, with 57–60 articles, those of chaetiger 2 and three short, with 28 and 35 articles respectively, those of chaetiger 4 longer, with 55 articles; remaining dorsal cirri alternating long and shorter ones, with marked difference of length between long and short cirri; in midbody, long cirri with more than 50 articles and short ones with about 25–30, sometimes 40 articles ( Fig. 15B, C ). Ventral cirri digitiform, inserted proximally, elongated, longer than parapodial lobes, or similar in length ( Fig. 15B, C ). Parapodial lobes conical, with pre- and postchaetal lobes, prechaetal longer than postchaetal. Compound chaetae falcigers, with distinctly bidentate blades, short spines on margin ( Fig. 16A, B, C ), and dorso-ventral gradation in length. Anterior parapodia each with 11–12 chaetae, blades 43 μm long above 28 μm long below ( Fig. 16A ); midbody chaetigers with eight compound chaetae, similar to those of anterior parapodia, but more robust, with thicker shafts, shorter blades and more markedly bidentate, blades 36 μm long above, 25 μm below ( Fig. 16B ). Posterior parapodia each with six compound chaetae, with thick shafts and a subdistal protuberance, short and markedly bidentate blades, small dorso-ventral gradation, about 26 μm long above, 21 μm below ( Fig. 16C ). Dorsal and ventral simple chaetae on far posterior segments, similar, bidentate, both teeth similar, short subdistal spines. Anterior parapodia each with five aciculae (sometimes 6–7 in larger specimens), three of them larger than remaining, distally pointed, and two smaller, one pointed and one distally bent ( Fig. 16D ), reducing to two on midbody parapodia, one larger and other smaller, pointed ( Fig. 16E ), and solitary on posterior parapodia, very thick, somewhat blunt distally, straight, protruding beyond parapodial lobes ( Fig. 16F ). Pygidium with two long anal cirri, each with about 20–24 articles, and one short median stylus. Pharynx long, extending through 10–11 segments; tooth conical, on anterior margin. Proventricle extending through 14 segments, with about 33 muscle cell rows.

Remarks. The Australian specimens agree with the Mediterranean specimens described as Syllis alternata Moore, 1908 by San Martín (2003) and later considered by Langeneck et al. (2018) as Syllis profunda Cognetti, 1955 , which was originally described as a subspecies of Syllis variegata Grube, 1860 . It is a species of large size (some Mediterranean specimens reach up to 40 mm long), with marked alternation of dorsal cirri length, being long, slender, whip-shaped. Preserved specimens lack colour pattern; however, some live Mediterranean specimens have a very slender orange transverse line on anterior margin of segments.

Licher’s (1999) description of S. alternata based on the type specimens from N. Pacific, shows compound chaetae with more elongated blades, provided with small proximal tooth; instead, both the Australian and Mediterranean specimens have more robust blades with a marked, triangular proximal teeth on blades. Although similar in body shape, they are two different species.

Habitat. In the Mediterranean this species lives in Posidonia oceanica rhizomes, calcareous biogenic concretions, dead corals and even as epibionts on some gorgonians, in some depth, absent on shallow habitats. In Australia it seems to live in shallow water habitats.

Distribution. Mediterranean. Indonesia. Australia (NSW, WA, NT). Red Sea. This widespread distribution should be confirmed by molecular studies as it may represent a suite of cryptic species.

Figures

FIGURE 1. Syllis armillaris (O. F. M̧ller, 1776). AM W.53831. A, anterior end, dorsal view. B, long and short dorsal cirri, midbody. C, falcigers, anterior parapodium. D, falcigers, midbody parapodium. E, falcigers, posterior parapodium. F, aciculae, anterior parapodium. G, aciculae, midbody. H, acicula, posterior parapodium. I, dorsal simple chaeta. J, ventral simple chaeta. Scale. A: 0.2 mm. B: 0.1 mm. C–J: 20 µm.

FIGURE 2. Syllis augeneri Haswell, 1920. AM W.32040. A, anterior end, dorsal view. B, long-bladed compound chaeta, anterior parapodium. C, falcigers, anterior parapodium. D, long-bladed compound chaeta, midbody. E, falcigers, midbody. F, long-bladed compound chaeta, posterior parapodium. G, falcigers, anterior parapodium. H, dorsal simple chaeta. I, ventral simple chaeta. J, aciculae, anterior parapodium. K, aciculae, midbody parapodium. L, acicula, posterior parapodium. Scale. A: 0.2 mm. B–I: 20 µm.

FIGURE 4. Syllis busseltonensis (Hartmann-Schröder, 1982), n. comb.AM W.53906.A, anterior end, dorsal view. B, falcigers, anterior parapodium. C, falcigers, midbody parapodium. D, falcigers, posterior parapodium. E, aciculae, anterior parapodium. F, aciculae, midbody parapodium. G, acicula, posterior parapodium. H, dorsal simple chaeta. I, ventral simple chaeta. Scale. A: 0.2 mm. B–I: 20 µm.

FIGURE 7. Syllis narranuk n. sp. Holotype, AM W.53791.A, anterior end, dorsal view. B, short and long midbody dorsal cirri. Scale. A: 0.2 mm. B: 0.1 mm.

FIGURE 15. Syllis profunda Cognetti, 1955. AM W.29503. A, anterior end, dorsal view. B, midbody parapodium with long dorsal cirrus, lateral view. C, midbody parapodium with short dorsal cirrus, lateral view.Scales. A: 0.1 mm. B, C: 0.1 mm

FIGURE 16. Syllisprofunda Cognetti, 1955.AMW.29503.A, falcigers,anterior parapodium.B,falcigers, midbody parapodium. C, falcigers, posterior parapodium. D, aciculae, anterior parapodium. E, aciculae, midbody parapodium. F, acicula, posterior parapodium. Scale: 20 µm.