A review of occurrence, distribution and alien status of Notodiaphana atlantica Ortea, Moro and Espinosa, 2013 and Liloa mongii (Audouin, 1826) (Mollusca: Heterobranchia) in the Mediterranean Sea

Notodiaphana atlantica and Liloa mongii are two cephalaspidean species described respectively from the Atlantic Ocean and the Red Sea, and considered widespread in their native ranges. Both species have also been recently recorded from the Mediterranean Sea, prompting some authors to consider them alien. Notwithstanding clear morphological differences in their shells, the two species have often been confused or misidentified in the literature, or specimens have been described with incorrect locality data. We hereby review the occurrence, distribution and status of both species in the Mediterranean Sea based on published data and examination of new material. Notodiaphana atlantica is considered a cryptogenic species with a range spanning from the western to eastern part of the basin. The presence of L. mongii in the Mediterranean is questioned until specimens that can be reliably assigned to this taxon or to any congeneric species are found in the area. Alien species inventories play an important role in regional policy and management decisions, thus requiring a high degree of confidence in the validity of species identification and their non-indigenous status. The present paper adds further evidence of the excess of “bibliographically introduced” alien records and reiterates the need for periodic re-evaluation of published data.

Revisiting the non-native insect fauna of Greece: Current trends and an updated checklist

Alien invasive species not only have adverse environmental impacts, they may also pose socioeconomic and human health threats. The increase in detected non-native (alien) and cryptogenic species, followed by the necessity for up-to-date scientific information on biological invasions, prompted a thorough literature investigation on the non-native entomofauna of Greece. Supplementing previous studies concerning Europe and Greece, a checklist for the non-native insect species of the country is provided, while their number is elevated from 266 to 469. Current trends regarding species richness and taxonomy, deliberate or accidental means of introduction, as well as their native range and trophic preferences are analysed and discussed. This publication illustrates the current state of non-native insects of Greece, highlighting the need for an effective early warning system integrated in national phytosanitary legislation, survey protocols and strategies towards the eradication and mitigation of their detrimental impacts.

Discovery of Wilsonosiphonia fujiae (Rhodomelaceae, Rhodophyta) from the Maldives Islands and transfer of Polysiphonia rhizoidea from Hawaiʻi to Wilsonosiphonia

Wilsonosiphonia is a newly described marine algal genus with three species. The genus was previously confused with the widely distributed taxon Polysiphonia, and because of this, the taxonomy and distribution of Wilsonosiphonia is likely underestimated. We report the discovery of a minute filamentous red alga, Wilsonosiphonia fujiae (Rhodophyta) in the Maldives Islands, a taxon which was considered endemic to Brazil. Specimens were collected at Fulhadoo, Goidhoo Atoll and Dhidhdhoo Islands, South Ari Atoll, which are ca. 160 km apart, during January and July, 2019, respectively. Thalli formed dense patches on the upper intertidal in regions of shaded rock. Both mitochondrial cox1 and plastid rbcL sequencing confirmed the occurrence of W. fujiae in the Maldives, which is also in agreement with morphological observations. Based on the low pairwise divergences of COI-5P and rbcL sequences between the Maldives and Brazil specimens, we suggest that W. fujiae is a recently introduced yet cryptogenic species in the Maldives. Additionally, as a result of our phylogenetic analyses, it became evident that sequences from the Hawaiian Islands, which were listed as members of the genus Polysiphonia, represent species-level diversity within the genus Wilsonosiphonia. Based on both morphological characteristics and the COI-5P phylogeny, we here reinstate Polysiphonia rhizoidea from Hawaiʻi and transfer it to Wilsonosiphonia, as W. rhizoidea comb. nov.

Atlantic fishes in the Mediterranean: using biological traits to assess the origin of newcomer fishes

Two important facets of global environmental change are alteration of climatic regimes and the introduction of alien species. From a biogeographical perspective, these 2 processes lead to very similar results: a change in the distribution of species. Here, we considered Atlantic fish species that are recent newcomers in the Mediterranean Sea, using biological traits to assess their origin. For this purpose, we first re-evaluated all records of Atlantic fish species in the Mediterranean (n = 103) to exclude those not considered recent newcomers (n = 33). Based on faunistic data, we classified the true newcomers into 4 origin categories: alien, vagrant, range-expansion or cryptogenic. Then, we compared biological traits of species we characterised as aliens (n = 7), vagrants (n = 14) or range-expanders (n = 23). Finally, we re-assessed the origin of cryptogenic species (n = 26) using multivariate discriminant analysis, measuring the distance of individual species to the centroids of aliens, vagrants or range-expanders, allowing us to infer their probable ‘mode of origin’. The body size, depth range, temperature range, habitat and ability to undertake long-distance migration were the most important traits that could be related to alien, vagrant or range-expanding fishes. It was possible to assign 10 cryptogenic species a specific origin category with reasonable confidence, while the remaining cryptogenic species combined trait values of different origin categories. These results indicate that biological trait analysis can be coupled with faunistic data to help assess the most likely origin of a newcomer species, thus informing management decisions.

First records of non-indigenous species in port of Arzew (Algeria: southwestern Mediterranean)

Maritime transport is considered to be one of the main factors to transfer non-indigenous species (NIS), through biofouling of ships’ hulls and ballast water. Therefore, ports and marinas constitute hot spots for the introduction of species carried by international shipping and therefore are important sites for initiating biological monitoring. In this study, the port of Arzew (Algeria, Southern Mediterranean) was surveyed for the presence of NIS and cryptogenic species. The fouling communities of floating submerged structures and the hull of a fishing vessel were sampled with a scraper blade. After fixing and separating, the organisms were identified to the lowest possible taxonomic level. The results revealed the presence of 10 NIS and cryptogenic species, including: 1 Ascidiacea, 2 Bryozoa, 3 Crustacea, 1 Mollusca 1 Porifera, and 2 Polychaeta. Five species are reported for the first time from the Algerian coast. This study contributes to the knowledge of non-native species on the Algerian coast and in the Southern Mediterranean and establishes a baseline dataset for future assessments of NIS in ports of Algeria.