Some observations on the morphology of Sclerasterias richardi a rarely encountered Mediterranean Sea star (Echinodermata: Asteriidae)

The presence of specimens of the asteroid Sclerasterias richardi(Perrier, 1882) in Maltese waters,with some new details of its morphology (observed by SEM) and with special reference to its madreporites,is reported

Mesophotic and Deep-Sea Vulnerable Coral Habitats of the Mediterranean Sea: Overview and Conservation Perspectives

Although the different communities distributed in the mesophotic and deep waters play a fundamental role in the functioning of the marine ecosystems, the assessment of their global distribution is still far to be achieved. This is also true in the Mediterranean Sea, where exploration technologies are revealing a large diversity of unknown communities structured totally or partially by corals, which represent vulnerable marine ecosystems (VMEs) according to FAO’s guidelines. This chapter aims to define and describe the main coral habitats of the mesophotic and aphotic zones of the Mediterranean, such as coralligenous formations, cold-water coral frameworks, coral forests and sea pen fields. The role of these habitats in providing benefit for a variety of invertebrates and fishes as well as a suite of ecosystem goods and services is highlighted. Fishing is one of the main anthropogenic impacts affecting Mediterranean coral habitats, and the current conservation measures are often ineffective. Ongoing attempts and future solutions aiming at the conservation of these VMEs are here discussed, including the fishing restriction in strategic areas characterized by lush coral communities, the implementation of controls against illegal fishery, the development of encounter protocols for vulnerable species and the use of observers onboard

Deep Sequencing of Mixed Total DNA without Barcodes Allows Efficient Assembly of Highly Plastic Ascidian Mitochondrial Genomes

Ascidians or sea squirts form a diverse group within chordates, which includes a few thousand members of marine sessile filter-feeding animals. Their mitochondrial genomes are characterized by particularly high evolutionary rates and rampant gene rearrangements. This extreme variability complicates standard polymerase chain reaction (PCR) based techniques for molecular characterization studies, and consequently only a few complete Ascidian mitochondrial genome sequences are available. Using the standard PCR and Sanger sequencing approach, we produced the mitochondrial genome of Ascidiella aspersa only after a great effort. In contrast, we produced five additional mitogenomes (Botrylloides aff. leachii, Halocynthia spinosa, Polycarpa mytiligera, Pyura gangelion, and Rhodosoma turcicum) with a novel strategy, consisting in sequencing the pooled total DNA samples of these five species using one Illumina HiSeq 2000 flow cell lane. Each mitogenome was efficiently assembled in a single contig using de novo transcriptome assembly, as de novo genome assembly generally performed poorly for this task. Each of the new six mitogenomes presents a different and novel gene order, showing that no syntenic block has been conserved at the ordinal level (in Stolidobranchia and in Phlebobranchia). Phylogenetic analyses support the paraphyly of both Ascidiacea and Phlebobranchia, with Thaliacea nested inside Phlebobranchia, although the deepest nodes of the Phlebobranchia–Thaliacea clade are not well resolved. The strategy described here thus provides a cost-effective approach to obtain complete mitogenomes characterized by a highly plastic gene order and a fast nucleotide/amino acid substitution rate

Spread of the non-indigenous ascidian Aplidium accarense (Millar, 1953) in the Eastern Mediterranean Sea: morphological and molecular tools for an accurate identification

The aplousobranch ascidian Aplidium accarense (Millar, 1953) was first described on the western coast of Africa, where it is considered native. Afterwards, this species was introduced along south-American Atlantic coasts, where it affected local shellfish farms through a massive colonization of both natural and artificial substrata. Aplidium accarense has been recently reported along Catalan coasts and in the Tyrrhenian Seas (Western Mediterranean) where it represents a non-indigenous species, only recorded in harbours and aquaculture farms thus far. These Mediterranean records support the hypothesis that A. accarense is currently expanding within the basin, representing a potential invasive species. In this study, several colonies of A. accarense were found for the first time on artificial substrata within the semi-enclosed basin of the Mar Piccolo of Taranto (Italy, Ionian Sea), in the Eastern Mediterranean. Here we provide an updated description of A. accarense combining both morphological and molecular approaches, in order to allow an accurate and reliable identification of this expanding species. Comparing the morphology of the specimens collected from Taranto with the previous descriptions, a slight intra-specific variability has been noticed. Therefore, we provide detailed comparisons of the specimens found in Taranto with all the other A. accarense sampled in other areas of the world, in order to highlight the intra-species variability. The correct identification of a potentially-dangerous species such as A. accarense, represents a needed step for environmental monitoring purposes and for implementing management strategies to mitigate the effects of non-indigenous species on natural ecosystems and human activities

Polyclinum constellatum (Tunicata, Ascidiacea), an emerging non-indigenous species of the Mediterranean Sea: integrated taxonomy and the importance of reliable DNA barcode data

Polyclinum constellatum is a colonial ascidian with a pantropical distribution, recently introduced into the Eastern Mediter-ranean Sea, indeed it was reported along Egyptian and Turkish coasts in 2016 and 2018, respectively. In the present study we report its presence along the coasts of Greece and Italy (Eastern and Central Mediterranean Sea, respectively), using an integrated approach combining morphological and molecular analysis. Colonies of P. constellatum were collected from artificial substrata in the harbour of Taranto (Ionian Sea) in November 2018 and in the marina of Heraklion (Crete, Aegean Sea) in October 2019. Remarkably, several colonies observed and collected in the Heraklion marina appeared as two or more masses joined at their base or fused together, often with different colour morpho-types. Here we provide their detailed morphological description and molecular characterization using a long fragment of the mitochondrial COI sequence as a DNA barcode. Furthermore, we present and discuss a comparative table of the main morphological features of all species of the genus Polyclinum known to date and an accurate analysis of the reliability of the Polyclinum COI sequence currently available. Our study proves that P. constellatum is further spreading in the Eastern Mediterranean Sea and has already reached the Central Mediterranean Sea. Moreover, the pres-ent study reveals the presence of erroneously assigned Polyclinum COI sequences in public databases and a possible synonymy between the species P. constellatum, Polyclinum indicum Sebastian, 1954 (accepted as Polyclinum sebastiani Brunetti, 2007) and Polyclinum madrasensis Sebastian, 1952. Overall, our data provide a useful tool for the accurate and reliable identification of this expanding species in other non-investigated areas and suggest the most likely vector of introduction of this non-indigenous species in the investigated localities

Macro- and megafauna recorded in the submarine Bari Canyon (southern Adriatic, Mediterranean Sea) using different tools

Macro- and megafauna were recorded in the submarine Bari Canyon, located in the southern Adriatic Sea (Mediterranean Sea) during an oceanographic cruise carried out in May-June 2012 and an experimental fishing survey conducted in November 2013. During the former, 20 benthic samples were taken using a Van Veen grab at depths between 268 and 770 m and four deployments of a baited lander, for approximately 43 hours of video records, were carried out at depths between 443 and 788 m. During the latter, eight longline fishing operations were conducted from 338 m down to 612 m. Eighty-five living benthic and bentho-pelagic species were recorded: 29 Porifera, 1 Cnidaria, 2 Mollusca, 11 Annelida, 1 Arthropoda, 19 Bryozoa, 3 Echinodermata, and 19 Chordata. Fifty-one species are new records for the Bari Canyon, and 29 species are new records for the Adriatic Sea. Among the Porifera Cerbaris curvispiculifer is a new addition for the Italian sponge fauna. The first confirmed record of living specimens of the bryozoan Crisia tenella longinodata is reported. A total of six Mediterranean endemic species have been identified, four Porifera and two Annelida. The bathymetric range of some species has been extended. New information acquired for deep sea species confirms their importance in the structure of cold-water coral communities. This study has updated knowledge on the biodiversity of the Adriatic Sea, as well as of the Bari Canyon in particular, one of the sites designated as “jewels of the Mediterranean” for which urgent conservation measures are needed

Eastward spreading of the invasive Rugulopteryx okamurae (Heterokontophyta, Dictyotales) in the Mediterranean: first record in the Adriatic Sea

The brown seaweed Rugulopteryx okamurae is currently included in the list of invasive alien species of European Union concern due to its rapid expansion that is causing both ecological and economic impacts. In this study, we report the first record of R. okamurae in the Southern Adriatic Sea, off the coast of Bari, Italy, currently representing the easternmost limit of its distribution in the Mediterranean Sea. Morphological observations combined with rbcL and psbA sequence analyses confirmed the taxonomic identification. Field surveys carried out between April 2023 and January 2024 highlighted the conspicuous occurrence of R. okamurae over a total surface of approximately 6.5 ha. Two main human-mediated pathways occurring near the sites of the first observation of the alien species may have been responsible for its introduction: the trade in living organisms for human consumption and maritime transport related to the proximity of the port of Bari to the invaded area. Future studies will aim to identify and implement practical, cost-effective management strategies to mitigate this alarming bioinvasion

The Status of \u3ci\u3ePosidonia oceanica\u3c/i\u3e at Tremiti Islands Marine Protected Area (Adriatic Sea)

Simple Summary: The seagrass Posidonia oceanica is the most important marine phanerogam of the Mediterranean Sea due to its meadows’ complexity, persistence, and extension. These habitats provide a suite of ecosystem goods and services, being of primary importance in marine conservation. Despite their central role in the coastal ecology, P. oceanica meadows are undergoing overall deterioration and fragmentation in the basin mostly due to anthropogenic impacts at local to global scales. In the last decades, several management measures have been proposed aiming to improve the meadow health conditions, while the periodic monitoring of P. oceanica meadows allows for verifying their effectiveness. Here, we report the results of the monitoring of P. oceanica at Tremiti Islands Marine Protected Area (Adriatic Sea, Italy) carried out in 2003, 2015, and 2020. A general worsening was observed, particularly enhanced by direct anthropogenic impacts mostly related to anchoring practices, as well as by a certain level of sedimentation possibly deriving from coastal development. However, the identification of these impacts and the correct management of human activities to mitigate them produced positive results in a relatively short time span. Abstract: Posidonia oceanica meadows are Mediterranean coastal habitats of great conservation importance. This study is focused on a meadow located at Tremiti Islands Marine Protected Area (Adriatic Sea, Italy), which was monitored in 2003, 2015, and 2020 to evaluate its health state over time in relation to coastal human activities, which have been highly affecting this MPA for the last 20 years. To assess any change in the physiognomy of the meadow, rhizome density, percentage coverage, and lower limit progressions and/or regression over time were evaluated by scuba diving, while the distribution and extension of the meadow were assessed through habitat mapping using a side-scan sonar. Moreover, phenological and lepidochronological analyses were performed on the collected rhizomes to assess the leaf area index (LAI, m2m2) and the rhizome age (lepidochronological years). Our study showed a general deterioration of P. oceanica meadow from 2003 to 2020, with a significant reduction of its absolute and relative rhizome density and LAI at almost all sampling stations, absence of renovation of the meadow, and lower limit regression and overall worsening of the main conservation status indicators. However, appropriate management actions, such as the establishment of mooring buoy fields, supported the improvement of the P. oceanica status at the local scale with a significant increase in density and LAI and the presence of active stolonization processes, suggesting that mitigation actions can play a crucial role in the conservation of this habitat. On the contrary, local anthropogenic impacts, especially anchoring and coastal development, markedly affect the resilience of P. oceanica meadows to global stressors, such as climate change