Syllis qamhiyn, Rodríguez & Martín & Fiege, 2020

Rodríguez, Yolanda Lucas, Martín, Guillermo San & Fiege, Dieter, 2020, New species and records of the genus Syllis Savigny in Lamarck, 1818 (Annelida: Syllidae) from Socotra Archipelago (Indian Ocean), Zootaxa 4742 (1), pp. 73-88 : 79-85

publication ID	https://doi.org/ 10.11646/zootaxa.4742.1.4
publication LSID	lsid:zoobank.org:pub:D2AA5CB8-118B-4E1B-9646-F23CA492118A
DOI	https://doi.org/10.5281/zenodo.3681213
persistent identifier	https://treatment.plazi.org/id/D7265A27-7C36-3940-3DCB-C422FD1F304D
treatment provided by	Plazi
scientific name	Syllis qamhiyn
status	sp. nov.

Treatment

Syllis qamhiyn View in CoL n.sp.

Figures 2–6 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6

urn:lsid:zoobank.org:act:A270D267-0901-4185-80E4-E6D0AAC48A49

Material examined. Holotype ( SMF 26713) Soc /ST–726, Ras Qataninh Bay, 12º21.293’N 53º32.659’E, under stones and coral rubble, 8–10 m, coll. T. Wehe 9.4.2000. 1 paratype, same collection data ( NHCY 0018 ); 1 paratype prepared for SEM, Soc/ST–725, Ras Qataninh Bay, dredge, 12º21.789’N 53º31.399’E to 12º21.780’N 53º31.390’E, 18–20 m, coll. T. Wehe 09.04.2000, ( SMF 26714, SEM-stub 1311). GoogleMaps

Diagnosis. Conspicuously thick and short dorsal cirri filled with gelatinous substance; reduced number of compound chaetae from midbody to posterior parapodia, with enlarged shafts and short blades, which become almost unidentate; blades not fused to shafts.

Description. Holotype complete specimen, 17.5 mm long, 0.69 mm wide, with 151 chaetigers ( Fig. 2A View FIGURE 2 ). One incomplete paratype with 134 chaetigers, and other complete, Paratype (SMF 26714), 18.5 mm long, 0,5 mm wide, with 160 chaetigers ( Fig. 4B View FIGURE 4 ). Body long and slender, filiform, without colour pattern ( Figs 2A, B, C View FIGURE 2 ; 4B View FIGURE 4 ). Prostomium semicircular to oval ( Figs 2A View FIGURE 2 ; 5A View FIGURE 5 ); four small eyes in trapezoidal arrangement. Palps similar in length to prostomium. Median antenna arising between anterior eyes, with 12–13 articles, shorter than combined length of prostomium and palps. Lateral antennae same length as median antenna, with 13 articles each ( Fig. 2A View FIGURE 2 ). Peristomium dorsally shorter than subsequent segments ( Figs. 2A View FIGURE 2 ; 5B View FIGURE 5 ). Dorsal tentacular cirri about 15–21 articles each; ventral tentacular cirri about 13–14 articles each. Dorsal parapodial cirri relatively thin on anterior segments, alternating relatively long (0.3 mm) and short (0.2 mm); longer cirri similar in length to body width at corresponding chaetiger, with about 17–19 articles, shorter ones about 7–11 articles each ( Fig. 2A View FIGURE 2 ); from midbody posteriorwards, dorsal cirri shorter than body width, each cirrus thicker in midlength, with about eight well-marked articles, with acute article distally ( Fig. 2 View FIGURE 2 A–D); most articles of these dorsal cirri filled with gelatinous substance ( Fig. 2D View FIGURE 2 ), articles covered by small pores ( Fig. 5F View FIGURE 5 ). Ventral cirri oval, shorter than parapodial lobes ( Figs 2D View FIGURE 2 ; 6D View FIGURE 6 ). Ventral area of parapodia with almost circular area of pores ( Fig. 6 View FIGURE 6 C–E) and internal gland ( Fig. 2D View FIGURE 2 ). Compound chaetae as heterogomph falcigers; anterior parapodia with about 10 falcigers each; falcigers with slender bidentate blades, proximal tooth distinctly shorter than distal one, and short spines on margin; blades with dorsoventral gradation in length, 42–20 μm long ( Figs 3A View FIGURE 3 ; 5C, D View FIGURE 5 ). Number of chaetae per parapodium progressively diminishing posteriorly, 4–5 in midbody ( Figs 3C View FIGURE 3 ; 5E, G, H View FIGURE 5 ) and 3–5 on mid-posterior and posterior parapodia ( Figs 3E View FIGURE 3 ; 6 View FIGURE 6 A–B), shafts becoming larger and blades shorter and minutely bidentate, with proximal tooth much smaller than distal one ( Fig. 3E View FIGURE 3 ). Midbody falcigers with blades 20–19 μm long, posterior body falcigers with blades similar, about 19 μm long. Dorsal and ventral simple chaetae not seen. Anterior parapodia with five slender aciculae each, distally rounded ( Fig. 3B View FIGURE 3 ), three in midbody parapodia ( Fig. 3D View FIGURE 3 ); posterior parapodia with two distally oblique aciculae each ( Fig. 3F View FIGURE 3 ). Pharynx long, extending through about 13 segments ( Figs 2A View FIGURE 2 ; 4B View FIGURE 4 ); pharyngeal tooth elongated, conical, acute, on anterior margin of pharynx ( Figs 2A View FIGURE 2 , 4A View FIGURE 4 ). Proventricle shorter than pharynx, through 9–10 segments ( Fig. 2A View FIGURE 2 ), with about 48–50 muscle cell bands. Pygidium small, with two anal cirri, with 7–8 articles each ( Fig. 6F View FIGURE 6 ).

Etymology. The name of the species refers to Dendrosicyos socotrana , the only species of Cucurbitaceae growing into tree form and original from Socotra Island. Its trunk resembles the shape of midbody cirri of S. qamhiyn n.sp. In soqotri language it is named qamhiyn .

Remarks. Syllis qamhiyn n.sp. is characterized by having short, thick, distally acute dorsal cirri on midbody and posterior parapodia, and reduced number of falcigers in these parapodia, with enlarged shafts and short, almost unidentate blades, not fused to shafts. Syllis qamhiyn n.sp. belongs to the same group of species of Syllis armillaris (O. F. Müller, 1771) and related species, the latter considered cosmopolitan but likely a species complex. The mid- and posterior body falcigers of Syllis armillaris also have almost unidentate blades, but they are not so short and the shafts are not as enlarged as in Syllis qamhiyn n.sp. ( San Martín 2003); furthermore, the mid- and posterior body dorsal cirri of Syllis armillaris are enlarged, but not so much as in Syllis qamhiyn n.sp. Similar differences are between Syllis qamhiyn n.sp. and S. pseudoarmillaris Nogueira & San Martín, 2002 from Brazil ( Nogueira & San Martín 2002); S. pseudoarmillaris has fewer number of articles on midbody dorsal cirri and the compound chaetae of these parapodia are clearly bidentate, with not enlarged shafts; furthermore, the pharynx and proventricle are longer in S. qamhiyn n.sp. Syllis gracilis Grube, 1840 , also considered a cosmopolitan species, and S. picta (Kinberg, 1886) , from the Indo-Pacific (including the Red Sea), have similar bodies, with enlarged mid- and posterior body dorsal cirri, but in these species at least one of the compound chaetae on these parapodia have fused blade and shaft ( San Martín 2003; Álvarez-Campos et al. 2015; 2017).