Syllis gracilis Fauvel, 1923

Linero-Arana, Ildefonso & Diaz Diaz, Oscarn, 2011, Syllidae (Annelida, Polychaeta) from the Caribbean coast of Venezuela, ZooKeys 117, pp. 1-28 : 12

Syllis gracilis Fauvel, 1923 Figs 3.23-3.24

Syllis (Syllis) gracilis Day 1967:241, fig. 12.1. m–p.– Gardiner 1976:139, fig. 12 l–n.– Uebelacker 1984:116-118, fig. 112 a–h.– Nogueira and San Martín 2002:68-72, figs. 7, 8.

Syllis gracilis Fauvel 1923:259 fig. 96 f–i.– Pettibone 1963:116, fig. 32 a–e.– Imajima 1966:248, fig. 49 a–k.– Taylor, 1971:212 –214.– San Martín 1992:178.- 2003:413-416, figs. 226 –227.– Gobin 2010 (list only).

Material examined.

BMPL297, (8); BMPL398, (4), associated with Chondrila nucula , 1-2 m depth; BMPL297, (2); BMPL398, (4), all specimens associated with Aplysina fistularis , 1-3 m depth; BMIL598, (4); BMPL297, (3); BMPL398, (16); all specimens associated with Ircinia felix , 1-2 m depth; GCET1030, (6), fine to coarse sand, 1 m depth.

Description.

Length to 19.5 mm,width 0.7 mm. Body with up to 107 chaetigers. Anterior segments with a pair of dark, dorsal, transverse stripes. Prostomium with two pairs of lentigerous eyes in trapezoidal arrangement. Median antenna with 14-20 articles; lateral antennae with 12-15 articles. Dorsal tentacular cirri with 12-18 articles, ventral ones with 6-12 articles. Dorsal cirri alternating longer, with 16-21 articles, and shorter, with 14-16 articles, diminishing posteriorly. Anterior chaetae compound, bidentate, falcigers (Fig. 3.23), replaced by thick, simple, ypsiloid chaetae (Fig. 3.24) on median chaetigers. Posterior chaetae compound, bidentate, falcigers and slender, bidentate dorsal and ventral simple chaetae. Acicula enlarged subdistally. Pharynx extending through 8-9 chaetigers, with 10 marginal soft papillae, and middorsal subdistal tooth. Proventriculus extending through 11-13 chaetigers, with 36-42 rows of muscle cells. Pygidium with a pair of anal cirri with 6-12 articles and midventral cirrus.

Distribution.

Cosmopolitan in temperate and tropical seas.