Research Article |
Corresponding author: Will Musk ( w.a.musk@hull.ac.uk ) Academic editor: Christopher Glasby
© 2016 Will Musk, Sarah Faulwetter, Paul McIlwaine.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Musk W, Faulwetter S, McIlwaine P (2016) First record of Streptosyllis nunezi Faulwetter et al., 2008 (Annelida, Syllidae) from the United Kingdom, and amendment to the genus Streptosyllis Webster & Benedict, 1884. ZooKeys 582: 1-11. https://doi.org/10.3897/zookeys.582.8006
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During a benthic survey of a Marine Conservation Zone located on the Skerries Bank in the English Channel off the south-west coast of England, three specimens of Streptosyllis nunezi
Polychaetes, simple ventral chaeta, generic amendment, identification key
Species of the genus Streptosyllis Webster & Benedict, 1884 are small-sized polychaetes living interstitially in shallow marine sediments of sand, muddy sand or sandy mud (
In this paper, Streptosyllis nunezi is reported from UK waters for the first time and is the second record of the species after its original description. Furthermore, additional material of S. websteri from both the UK and from Greece, and of S. campoyi from the UK was examined and a previously unreported chaetal type was found in all three species of the genus. The generic definition of Streptosyllis is emended accordingly below.
The Skerries Bank and Surrounds candidate Marine Conservation Zone (MCZ), situated off the south-west coast of England, was designated in November 2013 as part of the designation of 27 sites (
Specimens belonging to the genus Streptosyllis were found in the samples collected at sites GT193 (50.2537, -3.6058; depth 13.4 m) and GT204 (50.2429, -3.6110, depth 9.2 m) (Fig.
In addition, several Streptosyllis specimens in archive material of the Institute of Estuarine and Coastal Studies’ (IECS) were examined, which were collected during a benthic survey carried out by Natural England (NE) around the Scilly Isles in April 2009. Streptosyllis specimens were found at sites SC2.5 (49.9469, -6.2846; depth around 5–8 m), Sc9.3 (49.9078, -6.3436; depth 14.5 m), Sc9.7 (49.9042, -6.3401; depth 13.2 m) and Sc9.10E (49.9064, -6.3413; depth 11.8 m) from St. Mary’s Sound, Scilly Isles (Fig.
Additional specimens of Streptosyllis campoyi and Streptosyllis websteri from the IECS and of S. websteri from archive collections of the Hellenic Centre for Marine Research (HCMR) were studied for comparison; sampling details of the latter can be found in
During the identification phase of the analysis, three specimens of a Streptosyllis species with a distinctive hyaline hood on the blade and distal end of the shaft of the compound chaetae and serrated simple dorsal chaetae with a hyaline hood were found in samples GT193 and GT204. A further six individuals with the same characteristics were discovered in the IECS archive material in samples Sc9.3, Sc9.7 and Sc9.10E. The chaetae found in the specimens were unlike those of any of the Streptosyllis species confirmed so far from UK waters: S. websteri Southern, 1914, S. bidentata Southern, 1914 and S. campoyi Brito, Núñez & San Martín, 2000 (
Streptosyllis Webster & Benedict, 1884: 711
Streptosyllis –
Streptosyllis –
Streptosyllis –
Streptosyllis arenae Webster & Benedict, 1884.
Body small. Four eyes, occasionally anterior pair of eyespots present. Palps fused at base, occasionally reduced to small papillae. Anterior parapodia with modified compound chaetae; sometimes with enlarged aciculae. Dorsal simple chaetae present, simple ventral capillary chaetae may be present in posteriormost chaetigers. Compound chaetae homogomph or hemigomph, falcigerous or spinigerous. Dorsal cirri smooth, pseudoarticulated or articulated with granular inclusions. Ventral cirri digitiform, sometimes longer than parapodial lobe. Pharynx unarmed with crown of soft papillae. Pygidium with one median and two lateral anal cirri.
Streptosyllis nunezi Faulwetter, Vasileidadou, Papageorgiou & Arvanitidis, 2008: 5, figs 4–6.
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.
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.
Streptosyllis nunezi, A anterior parapodium with falcigers with short blades B parapodium, mid-body C, D falcigers with elongated blade, mid-body; E falciger with elongated blade, posterior chaetiger F dorsal simple chaeta G posterior parapodium with ventral simple chaeta (arrow) H aciculae of chaetigers 2–6 (numbered) I acicula, mid-body. Scale bars: 10 µm (A–G, I), 20 µm (H).
Except for the presence of ventral chaetae and the aciculae protruding from the parapodium, all examined animals correspond well to the original description by
Mediterranean Sea (Crete, Italy), northeastern Atlantic (Canary Islands, Scilly Islands, Skerries Bank)
Occurs in fine to coarse sandy substrates in shallow waters (1–20 m).
Streptosyllis campoyi Brito, Núñez & San Martín, 2000: 611, figs 5a–l.
Streptosyllis bidentata (non Southern) –
Streptosyllis campoyi –
3 individuals from Station Sc9.7, St. Mary’s Sound, Scilly Isles, 13.2 m depth, in coarse to medium sand.
All examined animals correspond well to the description provided by
Streptosyllis websteri Southern, 1914: 26, pl. II, figs 3 a–f.
Streptosyllis websteri –
15 individuals from Elafonisi Island, Crete, 0–1 m depth; 1 individual from Pahia Ammos, Crete (5 m depth), at both sites in coarse sand; 2 individuals from Station Sc2.5 Scilly Isles, depth around 5–8 m.
All examined animals correspond well to the description provided by
Streptosyllis arenae is morphologically the most similar species to Streptosyllis nunezi; it differs from S. arenae by the presence of the hyaline hood covering the distal end of the shaft of the compound chaetae, and the rounded teeth found on the shaft of the dorsal simple chaetae. Other Streptosyllis species which have a hyaline hood on the blades of their compound chaetae are S. biarticulata Hartmann-Schröder, 1991, and S. magnapalpa Hartmann-Schröder, 1981. Streptosyllis nunezi can also be distinguished from both these species again by the presence of the hyaline hood covering the distal end of the shaft of the compound chaetae, and the rounded teeth found on the shaft of the dorsal simple chaetae (
Streptosyllis arenae was recorded by
(adapted from
1 | Compound chaetae with hyaline hood-like structures around the blade and distal end of the shaft and a strong serration on the distal end of the simple dorsal chaetae |
S.
nunezi
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– | Compound chaetae without hyaline hood-like structures | 2 |
2 | Compound chaetae with indistinctly bidentate blades. Strongly enlarged aciculae in chaetigers 2–5 | S. websteri Southern, 1914 |
– | Compound chaetae with distinctly bidentate blades. Strongly enlarged aciculae in chaetigers 2–6 | 3 |
3 | Blades of compound chaetae with both teeth similar and close to each other. Aciculae of chaetiger 7 only slightly more slender than those of chaetiger 6 | S. bidentata Southern, 1914 |
– | Blades of compound chaetae with proximal teeth longer and well separated. Aciculae of chaetiger 7 distinctly more slender than those of chaetiger 6 | S. campoyi Brito, Núñez & San Martín, 2000 |
In conclusion, the findings of this study showed a significant northerly range extension for Streptosyllis nunezi previously only confirmed from the Canary Islands and the Mediterranean Sea. A single simple ventral chaetae in each of the two posteriormost segments was also discovered in this and two other species of Streptosyllis, resulting in an emended diagnosis of the genus.
The authors would like to thank Anita Franco (IECS) for help during the initial stages of this paper, Shona Thomson (IECS) for producing the maps, Sarah Peaty (Environment Agency) and Dr. Benjamin Green (Natural England) for providing PSA and survey data. The publication of this paper was financially supported by Cefas.