Streptosyllis nunezi Faulwetter, Vasileidadou, Papageorgiou & Arvanitidis, 2008

Musk, Will, Faulwetter, Sarah & McIlwaine, Paul, 2016, First record of Streptosyllisnunezi Faulwetter et al., 2008 (Annelida, Syllidae) from the United Kingdom, and amendment to the genus Streptosyllis Webster & Benedict, 1884, ZooKeys 583, pp. 1-11 : 4-6

Taxon classification Animalia Phyllodocida Syllidae

Streptosyllis nunezi Faulwetter, Vasileidadou, Papageorgiou & Arvanitidis, 2008

Streptosyllis nunezi Faulwetter, Vasileidadou, Papageorgiou & Arvanitidis, 2008: 5, figs 4-6.

Material examined.

3 individuals from the Skerries Bank, England, 9-13 m depth; 6 individuals from the Scilly Isles, England, 11-14 m depth, at both sites in coarse to medium sand.

Description.

Body ca. 5 mm long, for 64 chaetigers in the only complete animal. Head semi-circular with two pairs of eyes and two eyespots located anteriorly. Three smooth antennae, median one twice as long as lateral ones. Palps basally fused, forming two rounded lobes, not visible dorsally. Two pairs of smooth tentacular cirri, about as long as lateral antennae. Dorsal cirri about as long as or slightly shorter than body width, smooth anteriorly, after proventricular region at irregular distances with pseudo-articulations containing yellow granular inclusions. Ventral cirri digitiform, smooth, almost as long as parapodial lobes anteriorly and in midbody, longer than parapodial lobe posteriorly. Posteriormost 3 segments achaetous. Pygidium with single filiform ventral cirrus (2 lateral cirri missing?). Up to 8 compound falcigers in each parapodium. Shafts of compound chaetae with three hemigomph teeth, sometimes notched so that they appear as up to four teeth (Fig. 2 A–B). Blades of falcigers of two types: short ones (ca. 7-9 µm) and longer ones (ca. 15 µm), former ones occurring in anteriormost chaetigers, longer ones in two dorsalmost chaetae of midbody and in posterior chaetigers (Fig. 2 C–E). Short blades covered entirely by membrane forming blunt tip and notch alongside of blade; longer blades covered by membrane forming pointed tip if viewed laterally, blunt if viewed from top, and 1-2 teeth along cutting edge of blade (Fig. 2 C–D). Membrane of blades often extending to shaft, covering its top. Posteriorly, all blades of compound chaetae thin and elongated (Fig. 2E). One dorsal simple chaeta present per chaetiger, from anteriormost chaetigers, slightly curved, tip bluntly rounded, covered by membrane forming blunt tip. Strong serration on distal end just below hood, forming up to 4 large, round teeth (Fig. 2F). One ventral simple chaeta in each of two last posteriormost chaetigers (excluding developing ones), very thin, capillary-like (Fig. 2G). Single acicula per parapodium, distally knobbed, knob sometimes irregularly rounded with one side longer than the other, anteriorly sometimes protruding from parapodium. Aciculae slightly enlarged in segments 3, 4, and 5, about 1.5-2 times larger than those of preceding and proceeding chaetigers (Fig. 2 H–I). Pharynx through 3-5 segments, proventricle through 6 segments.

Remarks.

Except for the presence of ventral chaetae and the aciculae protruding from the parapodium, all examined animals correspond well to the original description by Faulwetter et al. (2008).

Distribution.

Mediterranean Sea (Crete, Italy), northeastern Atlantic (Canary Islands, Scilly Islands, Skerries Bank)

Ecology.

Occurs in fine to coarse sandy substrates in shallow waters (1-20 m).