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The honeycomb worm Sabellaria alveolata is a gregarious tube-dwelling polychaete that builds remarkable biogenic reefs in marine coastal waters. Sabellaria alveolata reefs are considered valuable marine habitats requiring protection measures for their conservation, as they play a key role in the functioning of coastal ecosystems. Sabellarid reefs are extensively developed along the Atlantic coasts of Europe and reported for the Mediterranean Sea and the Italian coasts, where large reefs have been recorded in several localities. Fragmentary information is available on their health status, Sabellaria reefs thus being listed as “Data Deficient” in the Red List of Marine Habitats. To fill this knowledge gap, this study focused on the analysis of the structure of three reefs found along the southern coast of Sicily. In particular, we aimed to assess their phases with respect to the natural cycle that characterizes the sabellarid reefs. Reef features were analyzed both on the macroscale, based on the bioconstruction size (diameter and thickness) and degree of fragmentation, and on the microscale, based on the measurement of worm density, opercular length and sand porch presence. This study reveals relevant differences among reefs of the studied locations. These differences we attributeto the temporal shift linked to the natural reef phases, albeit further analyses are needed to understand the possible effect of natural and anthropogenic sources of variation on the Southern Sicilian reefs. In conclusion, Sabellaria reefs are a unique and persistent habitat along the Sicilian coast requiring proper management and conservation measures.

The knowledge on the hard bottom polychaete assemblages in the Northern Adriatic Sea, a Mediterranean region strongly affected by environmental pressures, is scarce and outdated. The objective of this paper was to update the information on polychaete diversity and depict their patterns of natural spatial variation, in relation to changes in algal coverage at increasing depth. Hard bottom benthos was quantitatively sampled by scraping off the substrate from three stations at Sveti Ivan Island (North Adriatic) at three depths (1.5 m, 5 m and 25 m). Polychaete fauna comprised 107 taxa (the majority of them identified at species level) belonging to 22 families, with the family Syllidae ranking first in terms of number of species, followed by Sabellidae, Nereididae, Eunicidae and Serpulidae. Considering the number of polychaete species and their identity, the present data differed considerably from previous studies carried out in the area. Two alien species, Lepidonotus tenuisetosus, which represented a new record for the Adriatic Sea, and Nereis persica, were recorded. The highest mean abundance, species diversity and internal structural similarity of polychaete assemblages were found at 5 m depth, characterised by complex and heterogeneous algal habitat. The DISTLM forward analysis revealed that the distribution of several algal taxa as well as some algal functional-morphological groups significantly explained the observed distribution patterns of abundance and diversity of polychaete assemblages. The diversity of the North Adriatic hard bottom polychaete fauna is largely underestimated and needs regular updating in order to detect and monitor changes of benthic communities in the area.

Sabellida are widespread, diverse and abundant in marine benthic habitats. Their distribution patterns on hard-bottom substrates are poorly studied so far. Little is known about the factors influencing their distribution, including the protection regimes that are known to affect assemblage diversity. We analyzed hard-bottom Sabellida at 1.5 and 5 m depths at the Torre Guaceto Marine Protected Area (MPA) (SE Italy) to describe diversity and distribution patterns, and to identify potential factors influencing their distribution. The Sabellida diversity varied significantly among stations and was higher at 5 m depth. No relation with the protection regime was found. Among environmental variables, only sedimentation appeared related, suggesting that local trophic features might have influenced the observed pattern. Among habitat formers, only the macroalga Halimeda tuna significantly explained part of the observed variation, probably due to its role as a basibiont for some Sabellida taxa. Other predictor variables of Sabellida distribution were the abundances of some invertebrate taxa, especially Syllidae and some filter feeders such as Sabellariida and Cirripedia, probably due to shared ecological requirements, rather than a direct effect on Sabellida distribution. The relation with the Syllidae remains obscure so far, albeit some kind of interaction (including predator/prey interactions) between these two taxa cannot be excluded. Sabellida should be taken into account when analyzing patterns of biodiversity of hard-bottom environments.

We report the description of nine new taxa of sabellid polychaetes belonging to the genus Amphiglena, of which diversity in the Mediterranean Sea has been widely underestimated. Examined material derived from both new collections along the Italian coast, including four CO2 vents/hydrothermal systems, and from a re-examination of older material previously attributed to A. mediterranera (Leydig, 1851) which was so far the only species of the genus reported for the Mediterranean area. The analysis revealed the presence of different taxa also consistent with a previous molecular analysis conducted on material from the Gulf of Naples and the Salento coast (Ionian Sea). This led to an increase in the number of species in the genus and to highlight the occurrence in the Mediterranean Sea of a high diversity within the genus. A key to the Mediterranean Sea species of Amphiglena is also provided. Some taxa, however, remain for the moment undescribed due to the poor preservation of the old material, and the lack of the type material for this taxon. A major revision of all the Mediterranean material previously attributed to A. mediterranea from both morphological and molecular points of view is needed.

Amphiglena aeoliensis sp. nov. (Figs 18, 19) Material examined. Holotype (MNCN 16.01 /18913): Italy: Panarea Island (Aeolian Archipelago), near the Bottaro crater, 27 September 2016, 8 m depth; station B2, 38°38’14.49”N 15° 6’34.47”E). Paratypes: MNCN 16.01 /18914: 8 specimens from the same locality and date as the holotype; PCZL: 19 specimens B2 site, 27 September 2016; PCZLS.A. 9.1. 79 specimens B3 site, 27 September 2016; PCZL S.A. 9.2. 39 specimens B3 site, September 2018 PCZL S.A. 9.3. The remaining material is in the MCG collection. Most material fixed in ethanol 70% (including the holotype and paratypes), and some in ethanol 95 %. Description. Holotype complete, with eight thoracic and 28 abdominal chaetigers. Body length 2.8 mm, branchial crown 1 mm long, maximum body width 0.43 mm. Natural dark brown colouration presents especially in the thorax and highlighting the mid-dorsal faecal groove, and ventral shields. (Fig. 18A). Crown with five pairs of radioles with 14 pairs of pinnules arranged in two longitudinal rows alternating along the radiolar length. Gap between pairs decreasing along the radiole from the base to the distal end, with the first two basal pairs more separated from the others. Pinnules slender and elongated, showing a similar length (1/4 of the total radiolar length) with the distal pairs and the first two basal pairs slightly shorter. Tip of radioles elongated as long as pinnule length (measuring 1/4 of the total radiolar length) and with a blunt end (Fig. 18C). Radiolar skeleton with two rows of cells. Dorsal lips with pointed dorsal radiolar appendages clearly shorter and wider than the pinnule, being 1/7 of the total radiolar length. Anterior peristomial ring even in height all around and visible also ventrally. Posterior peristomial ring low. Ventral basal flanges high, extending as prominent ridge from base of ventralmost radioles, across anterior peristomial ring but appearing not connected (Fig. 18D, E). Peristomial eyes not visible. Pygidial eyes present, as clusters of brown spots on lateral margins of pygidium. Thorax longer than wide. First thoracic chaetiger bearing only 3 chaetae similar in shape to the thoracic superior chaetae. From the second to the eighth thoracic chaetiger, 6 uncini in each torus with well developed breast, large distance to main fang, with approximately four rows of long teeth above main fang, and short handles long 1/3 of the total uncinus’ length (0.30) (Fig. 19A). Companion chaetae with straight shaft and short mucro (Fig. 19B). Second to eighth thoracic chaetigers with 4 chaetae, of which one superior broadly hooded chaeta (Fig. 19D) and three paleate chaetae on each thoracic chaetiger, with short mucro (Fig. 19E). Five abdominal uncini with similar-sized small teeth above the main fang, higher than thoracic ones and with short handle; the uncini are also larger in height than the other species, as in A. vulcanoensis sp. nov. (Fig. 19C). Up to 3 abdominal broadly-hooded neurochaetae, becoming narrower and with a more geniculate appearance in the last segments (Fig. 19G, F). A pair of brown/red spermathechae present at the base of dorsal lips. Staining pattern. In both, thorax and abdomen stain only ventral shields overlapping the natural brown colouration. Colouration pattern wide on both thorax and abdomen following the shape of the segments, but not reaching the tori (Fig. 18B). Variation. Individuals always with 8 thoracic chaetigers and up to 28 abdominal chaetigers. Mean body length of 2.55 mm and mean crown length of 1.08 mm. Peristomial eyes visible only in few specimens. Up to 8 thoracic uncini and 6 abdominal one (Table 1). Remarks. The new taxon is very characteristic in its colouration, although variable in intensity among specimens, as well as for its very compact appearance. This dark brown colour pattern is quite unusual among Amphiglena species. Peristomial rings and basal ventral flanges are quite similar to A. cf. mediterranea, from which it is distinguished for the first peristomial ring visible also ventrally, for the staining pattern, for a more compact appearance with wider and lower segments, but especially for the short handle of thoracic uncini.Among the non Mediterranean species, the new taxon is similar to A. nishi Capa & Rouse, 2007 described from Japan, especially in the shape of peristomial rings and ventral basal flanges. This species is however a smaller taxon with only 4 radioles. Etymology. The species is named from the type locality, the Aeolian Archipelago (north Sicily) where the species was collected. Distribution and ecology. This species is one of the most abundant taxa of the benthic community associated to the brown macroalga Cystoseira brachycarpa, dominating the rocks around the Bottaro crater and the hydrothermal system around it (see Auriemma et al. 2019, for a description of the collection area). Its local distribution in the area and its relationship with another new congeneric species are discussed below., Published as part of Giangrande, Adriana, Putignano, Matteo, Licciano, Margherita & Gambi, Maria Cristina, 2021, The Pandora's box: Morphological diversity within the genus Amphiglena Claparède, 1864 (Sabellidae, Annelida) in the Mediterranean Sea, with description of nine new species, pp. 201-239 in Zootaxa 4949 (2) on pages 225-227, DOI: 10.11646/zootaxa.4949.2.1, http://zenodo.org/record/4636125, {"references":["Capa, M. & Rouse, G. W. (2007) Phylogenetic relationships within Amphiglena Claparede, 1864 (Polychaeta: Sabellidae), description of five new species from Australia, a new species from Japan, and comments on previously described species. Journal of Natural History, 41, 327 - 356. https: // doi. org / 10.1080 / 00222930701194938","Auriemma, R., De Vittor, C., Esposito, V., Gaglioti, M. & Gambi, M. C. (2019) Motile Fauna associated to Cystoseira brachycarpa along a gradient of Ocean Acidification at a vent system off Panarea (Aeolian Islands, Italy). Biologia Marina Mediterranea, 26 (1), 216 - 219."]}

Amphiglena pithecusensis sp. nov. (Figs 6, 7) Material examined. Holotype (MNCN 16.01 /18901): Italy: Lacco Ameno (Ischia), 40°45’24.38”N 13°53’6.26”E, June 2012, 2– 3 m depth, on hard bottoms covered by macroalgae, mainly the brown alga Halopteris scoparia. Paratypes: MNCN 16.01 /18902: 5 specimens from the same locality and date as the holotype, 13 specimens from the same site of the holotype; PCZL S.A. 3.1.; 5 specimens from S. Anna rocks (Ischia-Cartaromana Bay), 40°43’34.58”N 13°57’35.98”E, 26 August 2014. PCZL S.A. 3.2. Most material fixed in formalin 4% (including holotype and paratypes) and preserved in 70% ethanol, some material fixed in ethanol 95 %. Description. Holotype complete, with eight thoracic and 24 abdominal chaetigers. Body length 2.5 mm (branchial crown 1.5 mm); width 0.4 mm (Table 1). Body light brown coloured on ventral side and with a flattened abdomen (Fig. 6A). Crown with five pairs of radioles with 12 pairs of pinnules arranged in two longitudinal rows slightly alternating along the radiolar length. Gap between pinnules pairs decreasing along the radiole, with the first basal pair appearing slightly more separated from the others. Pinnules all of similar length, measuring about 1/4 of the total radiolar length, except first basal pair and the two distal pairs slightly shorter. Tip of radioles elongated, reaching almost 1/3 of the total radiolar length, thinning toward its blunt end (Fig. 6C). Anterior peristomial ring not visible. Posterior peristomial ring higher ventrally with a well separated ventral incision and margins with an inflated appearance (Fig. 6D, E), connected to ventral basal flanges extending as prominent ridges from the peristomial ring to the base of ventral-most radiole. Peristomial eyes brown. Dorsal lips measuring 1/5 of the radiolar length. Pygidial eyes present as small clusters of red spots on lateral margins of pygidium. Thorax longer than wide. First thoracic chaetiger bearing only 2 chaetae similar in shape to superior chaetae of the following chaetigers. From the second to the eighth thoracic chaetiger, 7 uncini in each torus, with a short handle approximately 1/4 of the total uncinus length (0.31), with approximately four rows of teeth above main fang, and with rounded and flattened breast (Fig. 7A). Companion chaetae present, with straight shaft and short mucro (Fig. 7B). Two superior broadly hooded chaetae (Fig. 7D); 3 inferior paleate chaetae with short mucro as long as the paleate region (Fig. 7E). Three abdominal uncini, with similar-sized small teeth above the main fang, with short-handle and appearing higher than long (Fig. 7C). Two abdominal broadly hooded chaetae, similar, but longer, to the thoracic paleate chaetae both in anterior and median abdominal segments (Fig. 7F, G). Spermathechae visible brown/red coloured. Staining pattern. In both thorax and abdomen stain only the ventral shields, with a very narrow pattern especially in the abdomen remaining poorly stained (Fig. 6B). Variation. Individuals with 8 thoracic chaetigers and up to 24 abdominal segments. Mean body length of 2.1 mm and mean crown length of 1.3 mm (Table 1). Crown asymmetrical in some specimens composed of 11 radioles (5 pairs +1). Remarks. Specimens similar in external morphology to A. aenariensis sp. nov. previously described, but distinguished from that species by having slightly longer handles of the thoracic uncini, although not as long as in A. cf mediterranea. Moreover, hooks are proportionately smaller. Other differences are in a different ratio between body and crown (Table 1), in the narrow paleate chaetae in the thorax and abdominal chaetae of the mid body chaetigers which in A. aenariensis appear more geniculate and longer. Differences also in the ventral shape of the posterior peristomial ring with slight inflated margin, and in the shorter dorsal lips, and the ventral shield stain in this taxon appears less intense and narrower especially in the abdomen. Finally, the space between the pinnules in the radioles appears wider than in A. aenariensis sp. nov.. Etymology. Named from type locality. Lacco Ameno represents the first site of settlement of the ancient Greek populations (Eubei) at Ischia in the 8 th century BC, who called the island Pithekoussai, or Pithecusae in ancient Latin, due to the production of the local clay pottery. Distribution and Ecology. This species belongs to a group of similar taxa that are abundant around the coast off the Ischia Island. This species is present all around Ischia on hard bottoms with different algal cover, as well as on Posidonia oceanica seagrass beds under “normal pH condition”, except at the San Pietro site, where a form similar to A. mediterranea is present.

Genus Amphiglena Claparède, 1864 Type species: Amphicora mediterranea Leydig, 1851, subsequent designation by Bush (1905). The following diagnosis is based on that by Fitzhugh, 1989, revised by Capa & Rouse (2007). Diagnosis: Small-sized sabellin species bearing 5 to 8 pairs of radioles; radiolar skeleton with two rows of cells. Palmate membrane and radiolar flanges absent. Dorsal lips with dorsal radiolar appendages; dorsal pinnular appendages absent. Ventral lips absent; parallel lamellae absent. Ventral basal flanges of branchial crown present, as a pair of thin, erect, membranous flanges extending from the base of radioles and posteriorly across the anterior peristomial ring to proximal region of ventral-most radioles. Peristomial ring generally divided by a mid-ventral incision. Anterior margin of anterior peristomial ring low, of equal height all around, but often not visible all around because thinner and fused to the posterior ring. Posterior peristomial ring longer than the anterior ring with anterior margin horizontal or prolonged ventrally on both sides of the mid-ventral incision. Posterior peristomial ring collar absent. Variable number of thoracic chaetigers. Superior thoracic notochaetae broadly-hooded. Inferior thoracic notochaetae paleate, arranged in single transverse row. A single transverse row of abdominal neurochaetae assumed to be anterior row (posterior row absent); composed of elongate, broadly hooded chaetae. Thoracic uncini with teeth above main fang of equal size; hood absent; breast well developed, expanded; handles of variable length. Companion chaetae with distal end slightly inflated, dentate and with a thin mucro extending from this. Abdominal uncini with main fang surmounted by teeth of equal size; breast well developed, handles very short. Abdominal chaetiger not numerous. Pygidial eyes present., Published as part of Giangrande, Adriana, Putignano, Matteo, Licciano, Margherita & Gambi, Maria Cristina, 2021, The Pandora's box: Morphological diversity within the genus Amphiglena Claparède, 1864 (Sabellidae, Annelida) in the Mediterranean Sea, with description of nine new species, pp. 201-239 in Zootaxa 4949 (2) on page 204, DOI: 10.11646/zootaxa.4949.2.1, http://zenodo.org/record/4636125, {"references":["Claparede, E. (1864) Glanures zootomique parmi les annelides de Port Vendres (Pyrenees Orientales). Memoires de la Societe de physique et d'histoire naturelle de Geneve, 17, 463 - 600. https: // doi. org / 10.5962 / bhl. title. 14827","Leydig, F. (1851). Anatomische Bemerkungen uber Carinaria, Firola und Amphicora. Zeitschrift fur wissenschaftliche Zoologie, 3, 325 - 332, pl. IX, figs. 4 - 7.","Fitzhugh, K. (1989) A systematic revision of the Sabellidae - Caobangiidae - Sabellongidae complex (Annelida: Polychaeta). Bulletin of the American Museum of Natural History, 192, 1 - 104.","Capa, M. & Rouse, G. W. (2007) Phylogenetic relationships within Amphiglena Claparede, 1864 (Polychaeta: Sabellidae), description of five new species from Australia, a new species from Japan, and comments on previously described species. Journal of Natural History, 41, 327 - 356. https: // doi. org / 10.1080 / 00222930701194938"]}

Amphiglena nisidensis sp. nov. ( Figs 8, 9) Material examined. Holotype (MNCN 16.01 /18903): Italy: Nisida Island (Naples), 40°47’31.52”N 14° 9’47.29”E, 14 November 2011; 2 m depth. Collected on hard bottom with algal cover, mainly Halopteris scoparia. Paratypes: MNCN 16.01 /18904: 6 specimens from the same locality and date as the holotype; 22 specimens from the same locality and date as the holotype PCZL S.A. 4.1. Most material fixed in formalin 4% (including holotype and paratypes) and preserved in ethanol 70%; some material fixed in ethanol 95 %. Description. Holotype complete with eight thoracic and 28 abdominal chaetigers. Body length 2.5 mm, with crown 1.8 mm long, and 0.4 mm wide. Body light brown coloured on ventral side and with flattened abdomen (Fig. 8A). Crown with five pairs of radioles with 12 pairs of pinnules of medium length each, arranged in two longitudinal rows with a small space gap between the pinnules of the same pair, and with space increasing at the base of the radiole. The pinnules appear longer in median position where they measure 1/4 of the total radiolar length, and becoming considerably shorter towards the end of the radiole. Tip of radiole long, slender and pointed (Fig. 8C). Dorsal lips measuring 1/5 of the total radiolar length.Anterior peristomial ring not visible. Posterior peristomial ring higher ventrally with a mid-ventral incision where low ventral basal flanges attach, extending as prominent ridges from base of ventral-most radioles (Fig. 8D, E). Small brown peristomial eyes present. Pygidial eyes present as clusters of red spots on lateral margins of pygidium. Thorax longer than wide. First thoracic chaetiger with only 3 chaetae similar in shape to the superior chaetae of the following chaetigers. From the second to the eighth thoracic chaetiger, 5 uncini on each torus. Thoracic uncini with rounded and flattened breast, with four rows of teeth above main fang, and with handles long approximately 1/3 of the total uncinus length (0.35) so considered between medium and short length (Fig. 9A). Companion chaetae present, with straight shaft and long mucro (Fig. 9B). Thoracic chaetae from second to eighth chaetigers, number 4, of which one superior broadly-hooded chaeta (Fig. 9D) and three paleate chaetae in inferior row with mucro long as the hood (Fig. 9E). Abdominal uncini in number of 3, with similar-sized small teeth above the main fang, higher than the thoracic one and with short handle (Fig. 9C). Three abdominal neurochaetae thin and broadly hooded, similar to paleate of the thorax but longer in the first abdominal segments (Fig. 9G) and becoming longer and more geniculate starting from mid abdomen (Fig. 9H). Spermathechae present brown/red coloured. Staining pattern. In both thorax and abdomen stain only ventral shields. Peristomium, thorax and abdomen showing an intense colouration in the central part, but with a pattern covering most of the segment width (Fig. 8B). Variation. Individuals have eight thoracic chaetigers and up to 31 abdominal chaetigers. Mean body length of 1.65 mm and mean crown length of 1.5 mm. (Table 1). Remarks. The material from Nisida is very similar morphologically to A. pithecusensis sp. nov. previously described. The specimens from Nisida, however, appeared highly flattened in the abdomen and with wider bands of stained tissue as wide as the thoracic segment. Moreover, specimens have a larger ratio between body and crown (Table 1), with a longer and slender tip of radioles and pinnules arranged in pairs, not alternating along the radiolar length. Thoracic uncini are also similar in the length of the handles but with a slender main fang. The main difference is, however in the shape of the ventral margin of the peristomial ring showing an incision without separated margins, and with a lower basal flange. Ventral peristomial ring appears similar to A. bondi Capa & Rouse, 2007, from which it is distinguished by the short handle of thoracic uncini, and by the number of radioles. Etymology. Named from type locality, the Island of Nisida, located between the Gulf of Naples and the Gulf of Pozzuoli. Distribution and Ecology. Distributed on hard bottoms with algal cover. This species belongs to the same group of similar taxa that includes specimens from Ischia vent and non-vent’s areas, except the San Pietro site.

Amphiglena vulcanoensis sp. nov. (Figs 16, 17) Material examined. Holotype: (MNCN 16.01 /18911): Italy: Vulcano Island-Baia di Levante vent system, 8 May 2013, 38°25’10.10”N 14°57’43.38”E; 1.5 m depth (Vizzini et al. 2017). Paratypes: MNCN 16.01 /18912: 3 specimens from same locality and date as the holotype; 49 specimens, all collected in the same locality and date as the holotype PCZL S.A. 8.1. Material fixed ethanol 95% (including holotype and paratypes). Description. Holotype complete, with eight thoracic and 32 abdominal chaetigers. Body length 4.2 mm, branchial crown 1.5 mm; maximum body width 0.5 mm, abdomen largely flattened. Yellow colouration presents especially in the thorax, highlighting the mid-dorsally faecal groove, and ventral shields (Fig. 16A). Crown with 7 pairs of radioles with 16 pairs of pinnules arranged in two longitudinal rows alternating along the radiolar length. The gap between pinnule pairs remaining constant along the radiole, with only the first basal pair more separated from the successive one. The pinnules show a variable length appearing very short and with a characteristic swell on the end, not observed in other species. The tip of radioles short and blunt (Fig. 16C). Dorsal lips with very long and rounded dorsal radiolar appendages, (1/3 of radiolar length). Radiolar skeleton with two rows of cells. Anterior peristomial ring not visible. Posterior peristomial ring low with two small ventral projections with low margin, ventral basal flanges thick and extending as prominent ridge from the base of the ventral-most radioles. Base of crown distinctly thick (Fig. 16D, E). Peristomial eye not visible. Pygidial eyes present as cluster of brown spots on lateral margins of pygidium. Thorax longer than wide. First thoracic chaetiger bearing only 3 chaetae similar in shape to the superior chaetae of the other thoracic segments. From the second to the eighth thoracic chaetiger, 7 uncini in each torus, with approximately five rows of similar-sized small teeth above the main fang and well-developed breast, going beyond the main fang and with large distance above main fang. Medium-short handles long around 1/3 of the total uncinus length (0.35); the uncini are also larger in height than the other species (Fig. 17A). Companion chaetae present, with straight shaft and short mucro (Fig. 17B). Second to eighth thoracic chaetigers with 5 chaetae of which one superior chaeta broadly hooded and four inferior paleate chaetae of two different typologies, one having a mucro long as the hood, the second showing a very short mucro and a reduced length (Fig. 17D, E, H). Four abdominal uncini on each torus with 4 teeth, uncini higher than longer and with a medium handle (Fig. 17C). Four broadly hooded abdominal neurochaetae similar to the inferior paleate chaetae both in the first and median abdominal segments, but the last becoming longer (Fig. 17F, G). Spermathechae light brown/coloured. Staining pattern. In both thorax and abdomen stain only ventral shields, intensely coloured on the peristomial ring, and abdomen with a narrow stained string (Fig. 16B). Variation. Individuals always with 8 thoracic chaetigers and up to 32 abdominal chaetigers. Mean body length of 3.7 mm and mean crown length of 1.3 mm. Up to 10 thoracic uncini on each torus and 7 abdominal uncini (Table 1). Remarks. This is a species larger than the other congeneric species, with a compact appearance and with the largest number of radioles of all Mediterranean species, and non Mediterranean species. In this aspect, it resembles the Australian species A. magna Capa & Rouse, 2007 from which it is distinguished by the length of handles of thoracic uncini, but also by the ventral peristomial shape. This feature is similar to A. terebro Rouse, 1993, which is a smaller species with fewer radioles and 12 thoracic chaetigers. Etymology. The species is named from type locality, the Island of Vulcano (Aeolian Archipelago, north Sicily). Distribution and Ecology. The species up to date has been collected only in Baia di Levante hydrothermal vent’ system of Vulcano island. This vent’s system is unique since it is not only acidified due to CO 2 emissions from the primary vent source (approx. 300 m from the collection area), but has also some sulphur (H 2 S) and is enriched by metal ions (see Vizzini et al. 2017, and references herein for a description of the system and its benthic community). Amphiglena vulcanoensis sp. nov. was collected with a few other polychaetes, among which Platynereis cf. massiliensis Moquin-Tandon, 1869 was the dominant species (Waege et al. 2017, Vizzini et al. 2017)., Published as part of Giangrande, Adriana, Putignano, Matteo, Licciano, Margherita & Gambi, Maria Cristina, 2021, The Pandora's box: Morphological diversity within the genus Amphiglena Claparède, 1864 (Sabellidae, Annelida) in the Mediterranean Sea, with description of nine new species, pp. 201-239 in Zootaxa 4949 (2) on pages 222-224, DOI: 10.11646/zootaxa.4949.2.1, http://zenodo.org/record/4636125, {"references":["Vizzini, S., Martinez-Crego, B., Andolina, C., Massa-Gallucci, A., Connell, S. D. & Gambi, M. C. (2017) Ocean acidification as a driver of community simplification via the collapse of higher-order and rise of lower-order consumers. Scientific Report, 7, 4018. https: // doi. org / 10.1038 / s 41598 - 017 - 03802 - w","Capa, M. & Rouse, G. W. (2007) Phylogenetic relationships within Amphiglena Claparede, 1864 (Polychaeta: Sabellidae), description of five new species from Australia, a new species from Japan, and comments on previously described species. Journal of Natural History, 41, 327 - 356. https: // doi. org / 10.1080 / 00222930701194938","Rouse, G. W. (1993) Amphiglena terebro sp. nov. (Polychaeta: Sabellidae: Sabellinae) from eastern Australia; including a description of larval development and sperm ultrastructure. Ophelia, 37, 1 - 18. https: // doi. org / 10.1080 / 00785326.1993.10430373","Waege, J., Valvassori, G., Hardege, J. D., Shulze, A. & Gambi, M. C. (2017) The sibling polychaetes Platynereis dumerilii and Platynereis massiliensis in the Mediterranean Sea: are phylogeographic patterns related to exposure to ocean acidification? Marine Biology, 164 (10), 199. https: // doi. org / 10.1007 / s 00227 - 017 - 3222 - x"]}

Amphiglena messapica sp. nov. (Figs 12, 13) Material examined. Holotype (MNCN 16.01/18907): Italy: Santa Caterina-Torre Inserraglio (Apulian Coast, Ionian Sea), 40° 8’22.13”N 17°58’47.31”E, collected in 2002 from hard bottom at 1 m depth, covered by Halopteris sp. and Dictyota sp. Paratypes: MNCN 16.01 /18908: 7 specimens from the same locality and date as the holotype; 118 specimens all collected in the same locality and date as the holotype PCZL S.A. 6.1. Most material fixed in formalin 4% (including holotype and paratypes) and preserved in ethanol 70%; some material fixed in ethanol 95 %. Description. Holotype complete, with eight thoracic and 28 abdominal chaetigers. Body length 3 mm, branchial crown 1 mm; maximum body width 0.35 mm (Fig. 12A). Crown with five pairs of radioles with 11 pairs of pinnules arranged in two longitudinal rows not alternating along the radiolar length. Gap between pinnule pairs constant along the radiole. Pinnules quite short and with a similar length (1/4 of the total radiolar length), being shorter only in the first two basal pairs and in the last two distal pairs. Radiolar tip reaching between 1/3 and 1/4 of the total radiolar length and with a blunt tip (Fig. 12C). Radiolar skeleton with two rows of cells. Dorsal radiolar appendages long 1/3 of total radiolar length. Anterior peristomial ring not visible. Posterior peristomial ring short but oblique, appearing as having pointed margin (Fig. 12D, E). Ventral basal flanges high extending as prominent ridge from base of the ventralmost radioles across the anterior peristomial ring and highly connected with the peristomial ring (Fig. 12D, E). Peristomial eyes not visible. Pygidial eyes brown spots on lateral margins of pygidium. Thorax longer than wide. The first thoracic chaetiger bearing only 3 chaetae similar in shape to the superior thoracic chaetae. From the second to the eighth thoracic chaetiger, 6 uncini on each torus, with well-developed breast, large distance to main fang, and approximately four rows of long teeth above main fang, and medium handles, measuring more than 1/3 of the total uncinus length (0.43) so that the uncinus appears longer than higher (Fig. 13A). Companion chaetae present, with straight shaft and long mucro (Fig. 13B). From the second to the eighth thoracic chaetiger, 2 superior broadly hooded chaetae (Fig. 13D) and 4 paleate chaetae in inferior group with mucro long as the hood (Fig. 13E). Four abdominal uncini with similar-sized small teeth above main fang, longer than thoracic ones and with short handle (Fig. 13C). Spermathechae not visible. Up to 3 abdominal hooded neurochaetae with hood similar to the inferior chaetae in the first abdominal segments (Fig. 13F) becoming longer and more geniculate in the median abdominal segments (Fig. 13G). Staining pattern. In both thorax and abdomen stain only ventral shields with a large rectangular pattern in the thorax, and a double clear squared pattern on each abdominal segment (Fig. 12B). Variation. Individuals always with eight thoracic chaetigers and up to 28 abdominal chaetigers. Mean body length of 2.3 mm and mean crown length of 0.9 mm (Table 1). Remarks. Although being a compact form like the previous described species, this taxon is larger and with a longer appearance, especially in the abdominal chaetigers. The handles of the thoracic uncini, although having a similar length as A. cf. mediterranea, appear more pointed. Amphiglena messapica sp. nov. differs from this taxon especially in the shape of the peristomial ring which is ventrally higher and with more developed basal flanges, connected to the peristomial ring, so that it appears as pointed. The staining pattern is similar to A. aenariensis sp. nov., and to all the related taxa of the group from the Gulf of Naples. This species is distinguished from this group of taxa for the length of the handles of the thoracic uncini, and for the body/crown ratio, this last feature being similar to A. cf. mediterranea (Table 1). Among the non Mediterranean taxa, A. gracilis Capa & Rouse (2007) has the most similar ventral peristomial appearance, however, this species does not have the peristomial edge so connected to the ventral basal flanges, moreover, A. gracilis is a very thin species with only four pair of radioles, has a shorter handle of thoracic uncini, and a longer dorsal radiolar appendages. Lastly A. messapica sp. nov. is among the few Mediterranean species not showing an alternate arrangement of the pinnnule rows along the radiole. Etymology. The species was named from the “Messapi”, an ancient tribe inhabiting in pre-Roman time the Southern Apulia (Salento), where the species was collected. Distribution and ecology. The species is distributed on shallow and sheltered hard shallow substrates., Published as part of Giangrande, Adriana, Putignano, Matteo, Licciano, Margherita & Gambi, Maria Cristina, 2021, The Pandora's box: Morphological diversity within the genus Amphiglena Claparède, 1864 (Sabellidae, Annelida) in the Mediterranean Sea, with description of nine new species, pp. 201-239 in Zootaxa 4949 (2) on pages 217-218, DOI: 10.11646/zootaxa.4949.2.1, http://zenodo.org/record/4636125, {"references":["Capa, M. & Rouse, G. W. (2007) Phylogenetic relationships within Amphiglena Claparede, 1864 (Polychaeta: Sabellidae), description of five new species from Australia, a new species from Japan, and comments on previously described species. Journal of Natural History, 41, 327 - 356. https: // doi. org / 10.1080 / 00222930701194938"]}

Amphiglena gravinae sp. nov. (Figs 14, 15) Material examined. Holotype: (MNCN 16.01 /18909): Italy: Adriatic Sea, Brindisi, 40°38’53.39”N 18° 0’42.01”E, in 1985, 5 m depth, on corallinae algae. Paratypes: MNCN 16.01 /18910: 5 specimens from the same locality and date as the holotype; 296 specimens, all collected in the same locality and date as the holotype. PCZL S.A. 7.1. Material fixed in formalin 4% and preserved in ethanol 70 %. Description. Holotype complete with 8 thoracic and 22 abdominal chaetigers. Total body length 4 mm, crown 0.6 mm; maximum body width 0.3 mm (Fig. 14A). Crown holding five pairs of radioles with 11 pairs of short pinnules arranged in two alternating rows of similar length (between 1/5 and 1/4 of the total radiolar length. The gap between pairs remains quite constant along the radiole. First basal pair and last distal pair with pinnules shorter than that in the medial radioles. Elongated radiolar tip, reaching more than 1/3 of the total radiolar length and of uniform width, and with a blunt tip (Fig. 14C). Radiolar skeleton with two rows of cells. Dorsal lips with long and pointed dorsal radiolar appendages (1/3 of crown length). Anterior peristomial ring with similar height all around, visible also on ventral side. Posterior peristomial ring elongate and connected to high ventral basal flanges, which extends as prominent ridge from base of ventralmost radioles (Fig. 15D, E). Peristomial eyes not visible, pygidial eyes present, as very small spots on lateral margins of pygidium. Thorax longer than wide. The first thoracic chaetiger bearing only 3 chaetae similar in shape to the thoracic superior chaetae. From the second to the eighth thoracic chaetiger, 6 uncini on each torus with well-developed breast, and approximately four rows of similar teeth above main fang, large space to main fang, handle elongated, substantially longer than 1/3 of the total uncinus length and considered long handles (0.52) (Fig. 15A). Companion chaetae present, with straight shaft and long mucro (Fig. 15B). Second to eighth thoracic chaetigers with 4 chaetae, one superior broadly hooded chaeta (Fig. 15D), and three inferior paleate chaetae with a short mucro, long slightly less than the hood (Fig. 15E). Four abdominal uncini on each torus with similar-sized small teeth above the main fang and medium handle (Fig. 15C). Four abdominal broadly hooded neurochaetae, but with a very large hood similar to the thoracic paleate chaetae, even if longer. The shape of the chaetae is similar along the abdominal segments even if in the last segments they become longer and with a more geniculate appearance (Fig. 15G, F). Pair of light spermathechae present at the base of dorsal lips. Staining pattern. In both thorax and abdomen stain only the ventral shields, with a pale colouration, abdomen with a double rectangle in each segment (Fig. 14B). Variation. Individuals always with 8 thoracic chaetigers and up to 30 abdominal chaetigers. Up to 7 thoracic uncini. Mean body length of 2.6 mm and mean crown length of 0.9 mm (Table 1). Remarks. This new taxon has a more elongate appearance than other species in the genus, including the peristomial rings, and the base of the crown appearing sometimes bearing a high basal web, and making difficult to see the separation between the peristomial ring and the base of the crown. In this feature it is very similar to A. panareensis sp. nov., which is the other elongate Mediterranean species, described in the present paper. The two species, however show a different development of both first and second peristomial rings. Among the non Mediterranean species, high developed ventral flanges are present also in A. lenae Capa & Rouse, 2007, but this is a thin and more compact species, with smaller radiolar appendages. The staining patter is similar to A. messapica sp. nov., even if it appears narrower and more elongated following the elongated shape of the segments. It is distinguished from this species by the shape of the peristomial rings and for the abdominal chaetae, maintaining a paleate appearance long all the abdomen. This feature is present also in A. nisidensis sp. nov., and in A. vulcanoensis sp. nov. where, however, chaetae are less broadly-hooded. Lastly, A. gravinae has the thoracic uncini with the longest handle compared to all the Mediterranean species here described, although very similar in shape to A. messapica sp. nov. Etymology. The species is named after the Dr. Maria Flavia Gravina who collected the material, in honor of her valuable contribution to the knowledge of the taxonomy and ecology of polychaetes, as well as for our estimation, long-lasting friendship and collaboration. Distribution and Ecology. The species was collected in a polluted and stressed area, characterized by the presence of high sedimentation rate, and in the vicinity of a power plant.

Amphiglena cf. mediterranea (Leydig, 1851) (Figs 2, 3) Material examined. 32+ 18 specimens Italy: from Ischia S. Pietro promontory (Ischia Island, Tyrrhenian Sea), 40°44’47.78”N 13°56’40.93”E; collected on macroalgae (mainly Halopteris scoparia) during the years 1975 (Fresi et al. 1983) and 2005 (Gambi M.C.) at 1-2 m depth; PCZL S.A.1.4; 36 specimens from Leghorn (Tyrrhenian Sea), 43°28’28.92”N 10°19’42.54”E, collected in 1986 at 3 m depth on rocky substrate covered by coralline algae (Giangrande 1988) PCZL S.A.1.2; 141 specimens from Portofino (Genoa, Ligurian Sea), 44°18’10.70”N 9°12’56.29”E, collected in 1980 from 3 to 5 m depth, on hard substrate with algal cover PCZL S.A.1. All the material fixed in formalin 4% and preserved in ethanol 70%. Description. Specimens from S. Pietro (Ischia Island, Italy) have 8 thoracic chaetigers and up to 27 abdominal ones (Fig. 2A), a mean body length of about 3.10 mm of which about 0.80 mm is the crown, maximum wide of 0.36 mm (Table 1). The crown is composed of up to 10 radioles (5 pairs) each bearing up to 20 pinnules (10 pairs), arranged in two longitudinal rows alternating along the radiolar length. The gap between pairs remaining quite constant along the radiole. The pinnules show a similar length (about 1/3 of the total radiolar length), with only the first two basal pairs and the last two distal pairs appearing shorter (between 2/3 and 1/2 of the pinnule in medial position). Radiolar tip measuring almost 1/2 of the total radiolar length, with a pointed end; the dorsal lips are around 1/5 of the total radiolar length. Spermathechae and peristomial eyes not visible, pygidial eyes ellipsoid red. First peristomial ring flattened and visible only dorsally (Fig. 2E). Second peristomial ring slightly higher ventrally, appearing separated and with rounded margins (Fig. 2D, F). High ventral basal flange not connected to the peristomial ring (Fig. 2D, F). Up to six thoracic uncini with handle of medium length (48) and with four teeth (Fig. 3A). Companion chaetae with long mucro (Fig. 3B). Superior thoracic chaetae broadly hooded (Fig. 3D). Three paleate chaetae with short mucro on each thoracic chaetiger (Fig. 3E). Abdominal uncini with short handle (Fig. 3C), abdominal chaetae as in the genus, appearing all similar from the first chaetigers to the last one (Fig. 3F, G). Staining pattern. Thorax and abdomen intensely coloured and appearing dark blue with the exception of the intersegmental grooves, abdominal segments completely stained (Fig. 2B, C). Remarks. Amphiglena mediterranea is the type species for the genus and is also the most common name used for material collected around the world, and widely reported as a cosmopolitan species (Day 1967; Hartmann-Schröder & Rosenfeldt 1989; Hartmann-Schröder 1990; Knight-Jones et al. 1991, 2017; Dauvin et al. 2003; Dorgham et al. 2013; Faulwetter et al. 2017), and is still reported in recent ecological and biodiversity studies (Gambi et al. 2016; Hutchings & Kupriyanova 2018) as well as in Mediterranean polychaete check-lists (e.g., Castelli et al. 2008; Faulwetter et al. 2017). However, no type material was deposited from the type locality in Nice (France), and the original description by Leydig (1851) (in German) was not highly informative. Other authors gave a description of this taxon: Claparéde (1864), Saint Joseph (1894) and Rioja (1923), or commented on it (Banse 1957; Fitzhugh 1990). The last detailed re-description was by Rouse & Gambi (1997) from individuals collected off Ischia Island (Gulf of Naples, Italy), however, due to the location, far from the type locality, it was not possible to designate a neotype from this material. A comparison of the descriptions of A. mediterranea over time suggests that a large morphological variability exists concerning size, number of chaetigers, and number of radioles that need further exploration (Tilic et al. 2019). The taxon here re-described and collected from Ischia S. Pietro is the most similar and well corresponding to the re-description of A. mediterranea by Rouse & Gambi (1997), for material collected in Ischia in 1994 (Castello Islet), on hard substrate with Cladophora sp. and Halopteris scoparia algal cover, at 1-2 m depth. It corresponds well with regards to the shape and length of handles of thoracic uncini, and in the number of radioles and compact appearance (Fig. 2A), even though the small basal flanges in the description of these authors were connected to the peristomial ring. Similar features are also present in specimens from Portofino having a crown/body ratio of 0.3. By contrast, specimens from Leghorn examined during this study are slightly smaller and with a crown/body ratio of 0.49 (Table 1). In the specimens examined from all these sites located along the Tyrrhenian coast, also the ventral peristomial ring is similar to that described in the material of Rouse & Gambi (1997), even if in the material from San Pietro (Ischia) the peristomial ring appears ventrally more opened and rounded (Fig. 2F) compared to that of material from Leghorn. Therefore, all these forms showed a very similar external appearance including the staining pattern with the abdomen fully coloured (Fig. 2B, C), this latter feature was not provided in the description by Rouse & Gambi (1997)., Published as part of Giangrande, Adriana, Putignano, Matteo, Licciano, Margherita & Gambi, Maria Cristina, 2021, The Pandora's box: Morphological diversity within the genus Amphiglena Claparède, 1864 (Sabellidae, Annelida) in the Mediterranean Sea, with description of nine new species, pp. 201-239 in Zootaxa 4949 (2) on pages 204-206, DOI: 10.11646/zootaxa.4949.2.1, http://zenodo.org/record/4636125, {"references":["Leydig, F. (1851). Anatomische Bemerkungen uber Carinaria, Firola und Amphicora. Zeitschrift fur wissenschaftliche Zoologie, 3, 325 - 332, pl. IX, figs. 4 - 7.","Fresi, E. Colognola, R., Gambi, M. C., Giangrande, A. & Scardi, M. (1983) Ricerche sui popolamenti bentonici di substrato duro del Porto di Ischia. Infralitorale fotofilo: Policheti. Cahiers de Biologie Marine, 24, 1 - 19.","Giangrande, A. (1988) Polychaete zonation and its relation to algal distribution down a vertical cliff in the western Mediterranean (Italy): a structural analysis. Experimental Journal of Marine Biology and Ecology, 120, 263 - 276. https: // doi. org / 10.1016 / 0022 - 0981 (88) 90006 - 8","Day, J. H. (1967) Sabellidae In: Polychaeta of Southern Africa. Part 2. Sedentaria. British Museum (Natural History) London, pp. 459 - 842.","Hartmann-Schroder, G. (1990) Teil 15. Die Polychaeten der subtropisch-tropischen und tropischen Ostku ¨ ste Australiens zwisch- en Lake Macquarie (New South Wales) im Su ¨ den und Gladstone (Queensland) im Norden. Mitteilungen aus dem Hamburgischen zoologischen Museum und Institut, 87, 41 - 87.","Knight-Jones, P., Knight-Jones, E. W. & Ergen, Z. (1991) Sabelliform polychaetes, mostly from Turkey's Aegean coast. Journal of Natural History, 25, 837 - 858. https: // doi. org / 10.1080 / 00222939100770561","Knight-Jones, P., Knight-Jones, E. W., Mortimer-Jones, K., Nelson-Smith, A., Schmelz, R. M. & Timm, T. (2017) Annelids (Phylum Annelida). In: Hayward, P. J. & Ryland, J. S. (Eds.), Handbook of the Marine Fauna of North-West Europe. Oxford University Press, Oxford, pp. 1 - 222.","Dauvin, J. C., Dewarumez, J. M. & Gentil, F. (2003) Liste actualisee des especes d'Annelides Polychetes presentes en Manche. Cahiers de Biologie Marine, 44, 67 - 95.","Dorgham, M. M., Hamdy, R., El-Rashidy, H. H. & Atta, M. M. (2013) First records of polychaetes new to Egyptian Mediterranean waters. Oceanologia, 55, 235 - 267. https: // doi. org / 10.5697 / oc. 55 - 1.235","Faulwetter, S., Simboura, N., Katsiaras, N., Chatzigeorgiou, G. & Arvanitidis, C. (2017) Polychaetes of Greece: an updated and annotated checklist. Biodiversity Data Journal, 5, e 20997. https: // doi. org / 10.3897 / BDJ. 5. e 20997","Gambi, M. C., Musco, L., Giangrande, A., Badalamenti, F., Micheli, F. & Kroeker, K. J. (2016) Polychaete distribution in shallow rocky reefs along a pH gradient of a vent system reveals winners and losers among closely related species. Marine Ecology Progress Series, 550, 121 - 134. https: // doi. org / 10.3354 / meps 11727","Hutchings, P. & Kupriyanova, E. (2018) Cosmopolitan polychaetes - fact or fiction? Personal and historical perspectives. Invertebrate Systematics, 32, 1 - 9. https: // doi. org / 10.1071 / IS 17035","Castelli, A., Bianchi, C. N., Cantone G., Cinar, M. E., Gambi, M. C., Giangrande, A., Itaci Sareri, D., Lanera, P., Licciano, M., Musco, L., Sanfilippo, R. & Simonini, R. (2008) Annelida Polychaeta. In: Relini, G. (Ed.), Checklist della flora e della fauna dei mari italiani. Parte I. Biologia Marina Mediterranea, 15 (Supplement 1), 323 - 373.","Claparede, E. (1864) Glanures zootomique parmi les annelides de Port Vendres (Pyrenees Orientales). Memoires de la Societe de physique et d'histoire naturelle de Geneve, 17, 463 - 600. https: // doi. org / 10.5962 / bhl. title. 14827","Rioja, E. (1923) Estudio sistematico de las especies Ibericas del suborden Sabelliformia. TrabaJos del Museo Nacional de Ciencias Naturales, Serie Zoologica, 48, 1 - 144.","Banse, K. (1957) Die Gattungen Oriopsis, Desdemona und Augeneriella (Sabellidae: Polychaeta). Videnskabelige Meddelelser fra Dansk naturhistorik FOrening i KJObenhavn, 119, 67 - 105.","Fitzhugh, K. (1990) A revision of the genus Fabricia Blainville, 1828 (Polychaeta: Sabellidae: Fabriciinae). Sarsia, 75, 1 - 16. https: // doi. org / 10.1080 / 00364827.1990.10413437","Rouse, G. W. & Gambi, M. C. (1997) Cladistic relationships within Amphiglena Claparede (Polychaeta: Sabellidae) with a new species and a redescription of A. mediterranea (Leydig). Journal of Natural History, 31, 999 - 1018. https: // doi. org / 10.1080 / 00222939700770511","Tilic, E., Feerst, K. & Rouse, G. (2019) Two new species of Amphiglena (Sabellidae, Annelida), with an assessment of hidden diversity in the Mediterranean. Zootaxa, 4648 (2), 337 - 353. https: // doi. org / 10.11646 / zootaxa. 4648.2.8"]}

In the framework of faunistic research conducted along the Apulian coast of Italy, three new species of thelepodid polychaetes are reported: Streblosoma pseudocomatus sp. nov., S. nogueirai sp. nov. and S. hutchingsae sp. nov. The taxonomic position of S. comatus is clarified and emended as Thelepus comatus. The described species are characterised by their C-shaped arrangement of uncini. The species are compared with their closest congeners and a synoptic table is provided for the species of Streblosma with C-shaped tori.

Filter feeding invertebrates are a relevant component of fouling assemblages with a pivotal role in ecological processes, since they improve water quality, enhance habitat heterogeneity and transfer organic matter from the water column to the benthos. They modulate the availability of resources to other species, with effects on the density and behavior of the surrounding macrofauna. The fanworm Sabella spallanzanii, one of the largest and most abundant Mediterranean filter feeders, provides a shelter for predation and a secondary substrate for algae and settlement for sessile invertebrates. We tested its role in driving the structure of fouling assemblages, through a removal experiment.The experiment was one-year-long, with four sampling times. The effect of the removal on the fouling community was marginal in terms of species richness and evenness, while the biomass showed important differences, with a constant increase over time with higher values in the samples containing S. spallanzanii. At the end of observations, the biomass reached the value of 3917 g DW m-2 in controls and 2073 g DW m-2 in treatments. The empty space left by fanworms was not used by other species with similar biomasses. It is possible that the functioning of fouling communities may, in the event of loss of species, fluctuate in terms of biomass mobilization to different compartments, either towards the pelagic compartment or to the detritus chain. In systems with reduced water turnover, this by-pass can have important consequences in terms of stability and ecological balance.

Aquaculture expansion is limited by the negative environmental impact of the waste and the need for alternative sources in the diet of reared fish. In this framework, for the first time, the survival rates, biomass gain, and fatty acid profiles of the polychaete Sabella spallanzanii and the macroalga Chaetomorpha linum, reared/cultivated as bioremediators in an integrated multitrophic aquaculture system (IMTA), were evaluated for their potential reuse applications. Results showed that these organisms represent a natural source of omega-3 and omega-6. On account of the overall results and the high biomass obtained as by-products, a preliminary study was performed employing both S. spallanzanii and C. linum as new dietary ingredients to feed different sized Dicentrarchus labrax. Fish survival rate, biomass growth, and specific growth rate were determined resulting in no significant differences between control and treated fishes. Histological analyses showed no alterations of the stomach tunica mucosa and submucosa in treated fishes. The eco-friendly approaches applied in the here-realized IMTA system could guarantee the achievement of sustainable by-products represented by the bioremediators S. spallanzanii and C. linum, as well as their reliability as a natural source of compounds beneficial to fish and human health.

Many marine organisms, including invertebrates, produce mucosal matrices having different functions. Besides mechanical protection, the mucus of many invertebrates contains specific compounds to make the animal poisonous and/or distasteful or irritating. The presence of antibiotic molecules is more advantageous for some invertebrates to contrast bacterial attack. In the present study we investigated the mucus of the Mediterranean annelid species Myxicola infundibulum living in a gelatinous envelope made up of dense mucus. Antimicrobial lysozyme-like and antioxidant activities were investigated to highlight the potential interest of the worm mucus as a source of bioactive compounds for biotechnological applications. In order to understand which kind of compounds could be responsible for the detected activities, the mucus of M. infundibulum was chemically characterized in terms of elemental composition, protein, lipid and carbohydrate content. Further chemical characterization was achieved by the advanced analytical technique of multinuclear and multidimensional NMR spectroscopy. NMR spectroscopy revealed the scarcity of lipids which preferentially resulted of alcoholic origin, or otherwise hydroxylate and several aminoacids (valine, leucine and alanine) in the aqueous extract in relation to the protein nature of M. infundibulum mucus. The mucus indeed is mainly composed by water (94% ± 0.7%) whereas its dry weight is made of proteins (36% ± 2.3%) followed by lipids (2.9% ± 0.07%) and carbohydrates (2% ± 0.31%). The mucus exerted a natural antibacterial lysozyme-like activity corresponding to 1.14 mg mL−1 of hen egg-white lysozyme and an antioxidant activity corresponding to 483.00 ± 79.22 nmolTE (Trolox equivalent)/mL sample as Trolox Equivalent Antioxidant Capacity (TEAC) and 276.26 ± 50.76 nmolTE/mL sample as Oxygen Radical Absorbance Capacity (ORAC). Therefore, our findings have potential implications due to the ongoing explosion of antibiotic resistant infections and the need to discover antibacterial agents. Additionally, the observed antioxidant activity is intriguing taking into account the need to find natural antioxidants useful for human health.

Streblosoma Hutchings and Glasby 1987: 222. Type species. Grymaea bairdi Malmgren, 1866, by original designation. Diagnosis Transverse prostomium attached to dorsal surface of upper lip; basal part usually with eyespots; distal part low, restricted to base of upper lip. Buccal tentacles all uniformly cylindrical. Peristomium forming lips, sometimes continuing dorsally as narrow annulation, with nuchal organs as thin ciliated row on anterior margin; short, hood-like upper lip, about as long as wide; lower lip also short, button-like, restricted to oral area. Short anterior segments, usually visible all around body, segment 1 frequently with ventral lobe posterior to lower lip, lobes on following anterior segments absent. Branchiae usually present, 2–3 pairs beginning from segment 2, each pair with numerous independent curled filaments, progressively tapering to tips, mid-dorsal gap between filaments of each side within pairs either present or absent. Anterior body highly glandular ventrally, swollen, smooth to strongly tessellated. Notopodia beginning from segment 2, extending for variable number of segments; conical and relatively short notopodia, distally bilobed, chaetae emerging between lobes. Winged notochaetae in both rows, those from anterior row broad-winged in several species, with wings somewhat twisted. Neuropodia beginning from segment 5 as fleshy ridges anteriorly and as raised pinnules after termination of notopodia. Neurochaetae throughout as short-handled avicular uncini, with dorsal button at anterior third of base or terminal, prow, if conspicuous, usually distinctly short, and strongly curved, convex base in most taxa; uncini usually in single, straight rows, a few species with uncini arranged in curved C-shaped to looped rows. Nephridial and genital papillae usually present, posterior to bases of notopodia of segments 4–7. Pygidium smooth to slightly crenulate (Hutchings et al. 2015, 2017)., Published as part of Lezzi, Marco & Giangrande, Adriana, 2019, New species of Streblosoma (Thelepodidae, Annelida) from the Mediterranean Sea: S. pseudocomatus sp. nov., S. nogueirai sp. nov. and S. hutchingsae sp. nov., pp. 2857-2873 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 52 (43 - 44) on pages 2859-2860, DOI: 10.1080/00222933.2018.1556357, http://zenodo.org/record/5178086, {"references":["Hutchings P, Glasby CJ. 1987. The Thelepinae (F. Terebellidae) from Australia together with a discussion of the generic and specific characters of the family. Bull Biol Soc Wash. 7: 217 - 250.","Hutchings P, Nogueira JMM, Carrerette O. 2015. Terebellidae (Annelida, Terebelliformia) from Lizard Island, Great Barrier Reef, Australia. Zootaxa. 4019 (1): 484 - 576."]}

Streblosoma nogueirai sp. nov. (Figures 4, 5, 8a) Type material Holotype: Torre Guaceto, Adriatic Sea, Italy, 40.722°’N, 17.792°’E, July 2000, hard bottom, 3 m (MNCN 16.01 /17965). Four paratypes, complete specimens, from same locality and date as holotype (MNCN 16.01 /17966; MNCN 16.01 /17967; MSNP P/4366; MSNP P/4367). Description Holotype complete, 9 mm long, 0.5 wide, with 49 chaetigers. Paratypes complete, 7– 9 mm long, 0.4–0.6 mm wide, 35–46 chaetigers. Transverse prostomium attached to dorsal surface of upper lip; basal part with eyespots irregularly arranged in a single row all around the surface, more concentrated laterally (Figure 4a,c). Long and annelated buccal tentacles. Peristomium forming lips; upper lip hood-like, expanded about as long as wide; lower lip button-like, restricted to oral area (Figure 4b). Segment 1 expanded, segment 2 shortest (Figure 4b). Three pairs of branchiae, on segments 2–4, segment 2 with two filaments on either side, segment 3 with about two filaments on either side and segment 4 with two filaments on either side; branchial filaments originating dorsally to notopodia, longest filaments about 1/3 of corresponding body width (Figure 4a,c). Anterior ventral surface glandular until segment 19; glandular surfaces progressively more swollen until segments 9–10, mid-ventral stripe visible from segment 14 to end of specimen (Figure 4a). Notopodia starting from segment 2 (first branchiate segment; Figure 4c) and extending until 22nd segment; bilobed notopodia, with flattened rounded lobes. Notochaetae arranged in two rows. Posterior row notochaetae as bilimbate capillaries slightly wider distally, and tapering to tip; notochaetae of anterior row shorter than those of posterior row, wings broader on one margin, basally bulbous, tapering to tip (Figure 5a). Neuropodia starting from segment 5, slightly raised from surface of body throughout. Uncini in straight rows until segment 14, then conspicuously curved (C-shaped) until posterior end, all with openings towards the dorsal side. Uncini breviavicular with dorsal button conspicuous, terminal, prow shorter than dorsal button with deep notch (Figure 5d); curved base, main fang conspicuous, secondary teeth in row of two teeth above main fang and a second row with much smaller teeth, one larger one inserted between teeth of first row, surrounded by several (4–6 or more, not clearly visible at 1000× magnification) smaller teeth at each side (dental formula: MF: 2:4–6). Unicini similar throughout body, including dental formula (Figure 5b,c,e). Nephridial and genital papillae not visible. Pygidium distally rounded, without papillae. MGS. There is no evident staining pattern; there are scattered white spots on the dorsal surface of posterior body (Figure 4d). Remarks Streblosoma nogueirai sp. nov. is similar to S. duplicata and S. curvus with which it shares the absence of a lateral extension of branchiae on chaetiger 1 and a similar pattern of notopodial distribution, with chaetae not reaching the posterior end of the body. Streblosoma nogueirai sp. nov. differs from S. duplicata in having eyespots in the peristomium, and from S. curvus in the general aspect of the anterior end (which appears swollen in S. curvus) and the shape of the uncinal prow (which is more conspicuous in S. curvus). The other species of Streblosoma with tori arranged in C-shaped rows have a lateral extension of branchiae on chaetiger 1 (Table 1). Streblosoma nogueirai sp. nov. is probably the species of Streblosoma identified by Giangrande et al. (1981) as S. hesslei, from Ischia (Naples), because of a similar general aspect of the anterior end (i.e. number of branchial filaments, upper lip shape), the presence of eyes and a similar dental formula. However, no further speculation can be made because the authors did not describe the torus arrangement and the material from the Ischia Port has been lost. Distribution and ecology Endemic for the Mediterraena Sea. From shallow hard-bottom substrates. Etymology The new species is named in honour of Dr João Miguel De Matos Nogueira, who contributed to the understanding of Terebellidae systematics., Published as part of Lezzi, Marco & Giangrande, Adriana, 2019, New species of Streblosoma (Thelepodidae, Annelida) from the Mediterranean Sea: S. pseudocomatus sp. nov., S. nogueirai sp. nov. and S. hutchingsae sp. nov., pp. 2857-2873 in Journal of Natural History (J. Nat. Hist.) (J. Nat. Hist.) 52 (43 - 44) on pages 2865-2868, DOI: 10.1080/00222933.2018.1556357, http://zenodo.org/record/5178086, {"references":["Giangrande A, Gambi MC, Fresi E. 1981. Two species of polychaetes new to the Mediterranean fauna. Boll Zool. 48: 311 - 317."]}

Lezzi, Marco, Giangrande, Adriana (2019): New species of Streblosoma (Thelepodidae, Annelida) from the Mediterranean Sea: S. pseudocomatus sp. nov., S. nogueirai sp. nov. and S. hutchingsae sp. nov. Journal of Natural History (J. Nat. Hist.) 52 (43-44): 2857-2873, DOI: 10.1080/00222933.2018.1556357, URL: http://dx.doi.org/10.1080/00222933.2018.1556357