Micro and nanoplastics are harmful to marine life due to their high level of fragmentation and resistance to degradation. Over the past two decades, marine coastal sediment has shown an increasing amount of microplastics being a sort of trap for debris wastes or chemicals. In such an environment some species may be successful candidates to be used as monitors of environmental and health hazards and can be considered a mirror of threats of natural habitats. Such species play a key role in the food web of littoral systems since they are litter-feeders, and are prey for fishes or higher trophic level species. A preliminary investigation was conducted on five species of small-sized amphipod crustaceans, with the aim to understand if such an animal group may reflect the risk to ecosystems health in the central Mediterranean area, recently investigated for seawater and fish contamination. This study intended to gather data related to the accumulation of plasticizers in such coast dwelling fauna. In order to detect the possible presence of xenobiotics in amphipods, six analytes were scored (phthalic acid esters and non-phthalate plasticizers), identified and quantified by the gas chromatography mass spectrometry (GC-MS) method. The results showed that among all the monitored contaminants, DEP and DiBP represented the most abundant compounds in the selected amphipods. The amphipod crustaceans analyzed were a good tool to detect and monitor plasticizers, and further studies of these invertebrates will help in developing a more comprehensive knowledge of chemicals spreading over a geographical area. The results are herein presented as a starting point to develop baseline data of plasticizer pollution in the Mediterranean Sea.

The lowfin chub, Kyphosus vaigiensis, is reported for the first time off Favignana Island, Sicily, central Mediterranean Sea. The specimen was identified on the basis of morphometric and meristic characters as well as mitochondrial DNA sequences (COI and 16S-rDNA). Two, perhaps three, Kyphosus species—K. bigibbus, K. sectatrix and K. vaigiensis—have been occasionally recorded in the Mediterranean. These species occur both in the Atlantic and Indo-Pacific regions but it is likely they entered the Mediterranean through the Strait of Gibraltar. However, it is unclear whether they have established reproductive native populations in the Mediterranean.

Hyalid amphipods living in coastal marine habitats are frequently included in ecological studies. The systematics of this taxon has been subject to profound changes, with an emphasis on the North Pacific fauna. Since a proper species delimitation is a prerequisite in taxonomic and ecological studies, Parhyale plumicornis (Heller, 1866) has been herein re-described, showing the criticisms and mismatches of various characters, which were previously used in dichotomous keys. This species was collected for the first time off the western coast of Sicily Island (Italy: central Mediterranean Sea). The male is peculiar, due to the second antennae heavily setose posteriorly and bearing long tufts of plumose ventral setae. In this paper, the species will be illustrated, and morphological polymorphism, molecular tags and ecological features will be reported. The species does not appear to be frequent in the Mediterranean Sea but it is important that marine biologists identify it accurately. A recent record, possibly ascribable to Parhyale plumicornis in the Red Sea, could indicate that this species is the first anti-lessepsian amphipod, which has migrated from the Mediterranean Sea towards the Red Sea. http://www.zoobank.org/urn:lsid:zoobank.org:pub:770BEDA1-3E06-464F-9D34-8AFE43592FCA

The first record in the Mediterranean Sea of the invasive aorid amphipod crustacean Grandidierella bonnieroides is presented. A widespread circumtropical species, recorded off the Saudi coast of the Arabian Gulf, the Red Sea and the Suez Canal, it may have been introduced into the Mediterranean through the Suez Canal. This tube-builder species of soft bottoms recently established a population in the polluted Haifa Bay, Israel. Further, this is the first Mediterranean record of the genus.

The beach flea Orchestia stephenseni was originally described by Cecchini (1928), and successively by Karaman (1973). The description of this species will be herein revised by focusing on the variation of the gnathopod 2 in males, as detected during its growth period. An analysis of DNA Barcoding was performed to support the assignment of the taxonomic species to five morphotypes. As the type specimen has not yet been designated, a neotype is assigned. The name of the species is here presented as a valid name as it satisfies the requirements of a Reversal of the Principle of Priority: Orchestia stephenseni takes precedence over the objective synonym Orchestia constricta A. Costa, 1853, in accordance with Article 23.9.2. of the International Code of Zoological Nomenclature. Orchestia stephenseni Cecchini, 1928 becomes nomen protectum, and Orchestia constricta nomen oblitum. The results presented in this paper also support the status of Orchestia stephenseni as a Mediterranean endemic species, thereby rejecting previous Atlantic records. The synonymies for O. stephenseni are revised accordingly.