New species and records of the genus Syllis Savigny in Lamarck, 1818 (Annelida: Syllidae) from Socotra Archipelago (Indian Ocean) Author Rodríguez, Yolanda Lucas Author Martín, Guillermo San Author Fiege, Dieter text Zootaxa 2020 2020-02-19 4742 1 73 88 journal article 10.11646/zootaxa.4742.1.4 bea08b82-f1da-4fca-987f-820360af0e8f 1175-5326 3674479 D2AA5CB8-118B-4E1B-9646-F23CA492118A Syllis bouvieri Gravier, 1900 Figure 1 Syllis bouvieri Gravier, 1900: 163 , pl. IX, fig. 40. Non Syllis bouvieri San Martín 1984: 374 , pls. 96, 97. Material examined. Soc/ST–18, MAP 78A, Qualansiyah Bay, 12º41.026’N 53º28.309’E , 5–6 m , coll. M. Apel 10.3.1999 , 1 specimen ( NHCY 0008). Soc/ST–92, MAP 151, Hawlaf Bay (off dune), 12º40.519’N 54º04.170’E , from Acropora cf. valida , 4–5 m , coll. M. Apel 21.3.1999 , 1 specimen ( SMF 26698). Additional material examined. Holotype ( MNHN 0146 ). Djibouti , Gulf of Aden . Description. Body long and slender, without colour pattern, 10.5 mm long, 0.8 mm wide, with approximately 64–67 chaetigers. Prostomium semicircular; 4 small reddish eyes in open trapezoidal arrangement. Palps robust, similar in length to prostomium. Median antenna arising between anterior eyes, with 38–40 articles, longer than combined length of prostomium and palps. Lateral antennae shorter than median one, with 20–22 articles. Peristomium dorsally similar in length to subsequent segments ( Fig. 1A ); dorsal tentacular cirri with about 30–33 articles, slightly longer than median antenna; ventral tentacular cirri with about 15–16 articles, slightly shorter than lateral antennae. Dorsal parapodial cirri long, pointed distally, with well-marked articles; first pair with about 41–44 articles, longer than body width. Midbody dorsal parapodial cirri with a slight alternation in length, about 30–26 articles, slightly thicker than anterior ones. Parapodia conical, distally slightly bilobed; ventral parapodial cirri digitiform, shorter than parapodial lobes. Compound chaetae heterogomph, with one or two dorsalmost chaetae having slender, elongated blades with both teeth similar and usually with rounded space in between, and moderate spines on margin, lightly curved upward ( Fig. 1B, D, F ); remaining falcigers distinctly shorter, nine on anterior parapodia, progressively diminishing to seven on midbody and six on posterior parapodia, blades bidentate with similar teeth, and moderate to short curved spines on margin ( Fig. 1B, D, F ). Blades of falcigers with dorsoventral gradation in length; slender, dorsalmost elongated blades 36 μm long on anterior parapodia, 47 μm on midbody, 42 μm long on posterior parapodia; remaining falcigers 30–23 μm long on anterior parapodia, 26–25 μm on midbody, 26–17 μm long on posterior parapodia. Anterior parapodia with three slender aciculae each, distally rounded ( Fig. 1C ), reducing to two in midbody parapodia, one subdistally slightly inflated with small oblique tip ( Fig. 1E ); posterior parapodia with one acicula each, distally bent at almost right angle, with acuminated tip ( Fig. 1G ). Dorsal simple capillary chaetae on posterior parapodia, thin, acute, apparently unidentate ( Fig. 1H ). Ventral simple capillary chaetae bidentate with some short spines on inner margin ( Fig. 1I ). Pharynx long, through about 8–9 segments; pharyngeal tooth elongated, conical, acute, on anterior margin of pharynx ( Fig. 1A ). Proventricle through six segments, with about 30 muscle cell rows.