Cut the rope: Short-term colonization of mooring lines by fouling community within the port of Livorno (Northern Tyrrhenian Sea, Western Mediterranean), focusing on alien species recruitment.

The early stages of fouling development on artificial substrates were examined for spatial-temporal variation in the commercial and touristic harbours (use destinations) of the port of Livorno (Tuscany, Italy). The experiment was carried out by submerging two types of experimental ropes with different surface textures, considering three times of submersion. Particular attention was paid to the colonization dynamics of non-indigenous species (NIS). The type of rope did not significantly affect fouling development. However, when the NIS assemblage and the whole community were taken into account, the colonization of ropes varied depending on the use destination. The touristic harbour exhibited a degree of fouling colonization higher than the commercial one. NIS were observed in both harbours since the beginning of colonization, eventually achieving higher population densities in the touristic harbour. The use of experimental ropes represents a promising quick cost-effective tool for monitoring of NIS presence in port environments.

Short-term colonization of fouling communities within the port of Livorno (Northern Tyrrhenian Sea, Western Mediterranean): Influence of substrate three-dimensional complexity on non-indigenous species establishment.

The influence of substrate morphology on early stages of fouling development was assessed through submerged experimental substrates with different morphological complexity. The experiment was carried out within commercial and touristic harbours of the port of Livorno (Italy), analysing the communities at three steps of colonization (14, 28, 42 days). We assessed the effect of substrate complexity on recruitment of non-indigenous species (NIS), combined with the influence of port use destinations. NIS were recorded in both use destination areas since the first step of colonization. Substrate morphological complexity significantly affected fouling colonization and particularly NIS assemblages. We found that high-complexity substrates are particularly suitable for NIS establishment in comparison with less complex ones. The touristic harbour exhibited a potential for fouling colonization higher than the commercial harbour. These results contributed to the understanding of factors involved in NIS establishment and spread, as well as in their spatial-temporal dynamics within port environments.

Heterogeneity within and among co-occurring foundation species increases biodiversity.

Habitat heterogeneity is considered a primary causal driver underpinning patterns of diversity, yet the universal role of heterogeneity in structuring biodiversity is unclear due to a lack of coordinated experiments testing its effects across geographic scales and habitat types. Furthermore, key species interactions that can enhance heterogeneity, such as facilitation cascades of foundation species, have been largely overlooked in general biodiversity models. Here, we performed 22 geographically distributed experiments in different ecosystems and biogeographical regions to assess the extent to which variation in biodiversity is explained by three axes of habitat heterogeneity: the amount of habitat, its morphological complexity, and capacity to provide ecological resources (e.g. food) within and between co-occurring foundation species. We show that positive and additive effects across the three axes of heterogeneity are common, providing a compelling mechanistic insight into the universal importance of habitat heterogeneity in promoting biodiversity via cascades of facilitative interactions. Because many aspects of habitat heterogeneity can be controlled through restoration and management interventions, our findings are directly relevant to biodiversity conservation.

Harbour type and use destination shape fouling community and non-indigenous species assemblage: A study of three northern Tyrrhenian port systems (Mediterranean Sea).

Fouling communities were studied in three port systems of Northern Tyrrhenian Sea (Western Mediterranean), focusing on the occurrence of non-indigenous species (NIS). For each port system two harbour types (large port and recreational marina) were sampled and, within each large port, fouling samples were collected considering two use destinations (commercial and touristic harbour). Among the 431 taxa identified, forty-two were alien or cryptogenic, four of which were new records for the study area. Harbour type and use destination shaped fouling communities and NIS assemblages, with their relative influence varying among different port systems. High fouling variability was detected within port environments and between different marinas. NIS showed the highest occurrence in large ports, in which the touristic harbour generally hosted the greatest amount. Therefore, the touristic harbours within large ports were identified as susceptible areas for NIS establishment and their possible subsequent spread at local scale through recreational maritime traffic.

Revision of the Laonice bahusiensis complex (Annelida: Spionidae) with a description of three new species.

The morphological reexamination of specimens previously identified as Laonice bahusiensis Sderstrm, 1920 from North European and Mediterranean collections, supported by the molecular analysis of freshly collected material, enabled the recognition of four different species in the region: the genuine L. bahusiensis, L. irinae n. sp. from North European waters, and L. grimaldii n. sp. and L. mediterranea n. sp. from the Mediterranean Sea. The morphology of these species is described and illustrated, and their distributions are clarified based on old and new materials. A key for their identification is also provided. The Bayesian analysis of the COI sequences (483 bp) showed that these four species form a clade, namely the L. bahusiensis species complex, morphologically characterized by the continuous dorsal crests on postbranchiate chaetigers in the adults. The genetic p-distances between the species of the complex ranged from 13.27% to 17.99%, while the intraspecific variability ranged from 0.6% to 1.57%. Together with the sister species Laonice cirrata (Sars, 1851), the L. bahusiensis complex formed the Laonice (Laonice) clade, which is morphologically characterized by the prostomium fused with the anterior peristomial margin. However, the monophyly of the L. bahusiensis complex, as well as that of the clade Laonice (Laonice), needs to be further supported through the analysis of a greater set of genes from a larger number of species.

An intertidal life: Combined effects of acidification and winter heatwaves on a coralline alga (Ellisolandia elongata) and its associated invertebrate community.

In coastal marine ecosystems coralline algae often create biogenic reefs. These calcareous algal reefs affect their associated invertebrate communities via diurnal oscillations in photosynthesis, respiration and calcification processes. Little is known about how these biogenic reefs function and how they will be affected by climate change. We investigated the winter response of a Mediterranean intertidal biogenic reef, Ellissolandia elongata exposed in the laboratory to reduced pH conditions (i.e. ambient pH - 0.3, RCP 8.5) together with an extreme heatwave event (+1.4 °C for 15 days). Response variables considered both the algal physiology (calcification and photosynthetic rates) and community structure of the associated invertebrates (at taxonomic and functional level). The combination of a reduced pH with a heatwave event caused Ellisolandia elongata to significantly increase photosynthetic activity. The high variability of calcification that occurred during simulated night time conditions, indicates that there is not a simple, linear relationship between these two and may indicate that it will be resilient to future conditions of climate change. In contrast, the associated fauna were particularly negatively affected by the heatwave event, which impoverished the communities as opportunistic taxa became dominant. Local increases in oxygen and pH driven by the algae can buffer the microhabitat in the algal fronds, thus favouring the survival of small invertebrates.

Annelids of the eastern Australian abyss collected by the 2017 RV 'Investigator' voyage.

In Australia, the deep-water (bathyal and abyssal) benthic invertebrate fauna is poorly known in comparison with that of shallow (subtidal and shelf) habitats. Benthic fauna from the deep eastern Australian margin was sampled systematically for the first time during 2017 RV 'Investigator' voyage 'Sampling the Abyss'. Box core, Brenke sledge, and beam trawl samples were collected at one-degree intervals from Tasmania, 42°S, to southern Queensland, 24°S, from 900 to 4800 m depth. Annelids collected were identified by taxonomic experts on individual families around the world. A complete list of all identified species is presented, accompanied with brief morphological diagnoses, taxonomic remarks, and colour images. A total of more than 6000 annelid specimens consisting of 50 families (47 Polychaeta, one Echiura, two Sipuncula) and 214 species were recovered. Twenty-seven species were given valid names, 45 were assigned the qualifier cf., 87 the qualifier sp., and 55 species were considered new to science. Geographical ranges of 16 morphospecies extended along the eastern Australian margin to the Great Australian Bight, South Australia; however, these ranges need to be confirmed with genetic data. This work providing critical baseline biodiversity data on an important group of benthic invertebrates from a virtually unknown region of the world's ocean will act as a springboard for future taxonomic and biogeographic studies in the area.

Two new deep-sea species of Laonice (Annelida: Spionidae) from the Mediterranean Sea.

Two new deep-sea species of the genus Laonice belonging to the subgenera Sarsiana and Appelloefia respectively, are described from the Mediterranean Sea. Complete specimens of the subgenus Appelloefia were studied for the first time, and the new information collected raised questions on the boundaries between the subgenera Appelloefia and Norgensia. The presence of characters in L. barcinensis sp. nov. previously considered to be exclusive to each these two subgenera suggests that they should be regarded as synonymous. The name Appelloefia being given precedence here, according to the Principle of the First Reviser. A correction is made regarding the depth range of Laonice rasmusseni Sikorski Pavlova, 2018.

The bastard grunt Pomadasys incisus (Bowdich, 1825) (Teleostei: Haemulidae) in Cyprus (eastern Mediterranean Sea) - a late arrival or just a neglected species?

Pomadasys incisus is a thermophilous coastal subtropical fish species belonging to the family Haemulidae. Originally described from Gambia, this species is widely distributed in the Eastern Atlantic from Galicia to South Africa. It has also been recorded in the Mediterranean Sea since 1840, presumably expanding its distribution in the next decades, although the species could have been already present in the basin, but simply overlooked until the mid XIX century. In this study, we first record P. incisus from Cyprus (eastern Mediterranean Sea), based on two opportunistic observations obtained through a citizen-science project and review the distribution of this species in the Mediterranean Sea. The present sighting raises the question on whether this species is a late arrival in the country or its presence has just been neglected until now. Based on present data, the most likely hypothesis is the latter one, with P. incisus occurring in low densities and being overlooked due to the absence of field studies. Whatever is true, some intrinsic or extrinsic factors may have played a role in limiting its spread or wide establishment in the above-mentioned country.

Non-indigenous species in Mediterranean ports: A knowledge baseline.

Port areas have been considered bioinvasion hotspots due to the concentration of several invasion vectors. However, the actual distribution of non-indigenous species (NIS) in Mediterranean ports is still poorly understood. Here we conducted a literature review with the aim to provide a knowledge baseline about NIS distribution in Mediterranean ports. NIS distribution in Mediterranean ports showed a high degree of heterogeneity in terms of studies across the whole basin, with a limited knowledge on both specific taxa and geographical areas, as well as a generally low proportion of investigated ports. The low rate of specific studies designed to monitor these particular environments may represent the main source of knowledge gaps. Mediterranean ports host NIS from all regions of the world, playing a key role in marine bioglobalization. Our synthesis represents the first baseline addressing the presence of NIS in Mediterranean ports, which may be useful to define plans of NIS management and strategies focusing on a network of recognised focal hotspots.

Molecular phylogeny of Paraonidae (Annelida).

A molecular phylogeny of the family Paraonidae was reconstructed on the basis of 16S rDNA, COI and 18S rDNA sequences obtained from 66 individuals belonging to 38 nominal species and subspecies. In agreement with previous findings, Paraonidae represent a monophyletic group, closely related to Sternaspidae. The topology obtained by the Bayesian and Maximum Likelihood analyses on the combined dataset was not consistent with the traditional view on Paraonidae evolution, nor with a recent cladistic analysis. According to our results, Paraonidae are divided in five clades. The earliest branching clade (Clade I) included five species of the genera Cirrophorus and Paradoneis, whereas the remaining species of these genera were included in the Clade II. The genus Levinsenia is monophyletic and represents the sister group of a highly supported clade including some morphologically homogeneous species previously assigned to the genus Aricidea, which is here described as Blakeia n. gen. The remaining species of Aricidea clustered in a clade that included Paraonis as well. Paraonis can be interpreted as a pedomorphic form of Aricidea, accounting for the strong morphological divergence between the two genera. For priority rules, Aricidea should be considered a junior synonym of Paraonis. None of the subgenera traditionally recognised within Aricidea were monophyletic; in addition, the shallow molecular divergence identified among species, in particular for 18S rDNA sequences, suggests that the adaptive radiation of the genus Aricidea is relatively recent. Phylogenetic relationships suggested that the median antenna is an ancestral character, which has been independently lost several times, though a long, cirriform antenna only occurs in the genus Aricidea. The ancestral number of pre-branchial chaetigers is most likely three, even though arrangements with a higher number of chaetigers have been probably achieved at least twice independently. Notopodial modified chaetae appear to be a plesiomorphy of Paraonidae and they have been lost subsequently, whereas neuropodial modified chaetae have been acquired at least thrice independently through the evolutionary history of the family. Paraonidae show a strikingly high occurrence of cryptic and pseudocryptic species; results of the present work suggest that environmental features play a crucial role in the diversification of this family, whereas the influence of geographical distance appears less pronounced. Lastly, despite their importance in deep-water environments, Paraonidae probably are a primarily shallow-water family, that radiated in the deep sea secondarily.

Syllidae (Annelida: Phyllodocida) from the deep Mediterranean Sea, with the description of three new species.

Despite almost two centuries of research, the diversity of Mediterranean deep-sea environments remain still largely unexplored. This is particularly true for the polychaete family Syllidae. We report herein 14 species; among them, we describe Erinaceusyllis barbarae n. sp., Exogone sophiae n. sp. and Prosphaerosyllis danovaroi n. sp. and report Parexogone wolfi San Martín, 1991, Exogone lopezi San Martín, Ceberio Aguirrezabalaga, 1996 and Anguillosyllis Day, 1963 for the first time from the Western Mediterranean, the latter based on a single individual likely belonging to an undescribed species. Moreover, we re-establish Syllis profunda Cognetti, 1955 based on type and new material. Present data, along with a critical analysis of available literature, show that Syllidae are highly diverse in deep Mediterranean environments, even though they are rarely reported, probably due to the scarce number of studies devoted to the size-fraction of benthos including deep-sea syllids. Most deep-sea Syllidae have wide distributions, which do not include shallow-waters. 100 m depth apparently represents the boundary between the assemblages dominated by generalist shallow water syllids like Exogone naidina Ørsted, 1843 and Syllis parapari San Martín López, 2000, and those deep-water assemblages characterised by strictly deep-water species like Parexogone campoyi San Martín, Ceberio Aguirrezabalaga, 1996, Parexogone wolfi San Martín, 1991 and Syllis sp. 1 (= Langerhansia caeca Katzmann, 1973).