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Plutonium zwierleini is a large plutoniumid centipede of great evolutionary interest, occurring with isolated populations along the western Mediterranean area, from Spain to Italy. Due to its rarity and the extreme paucity of available records, P. zwierleini is among the least known Mediterranean chilopods, and scarce information is currently available on its ecology and natural history. Based on an extensive sampling effort carried out in Sicily between 2022 and 2023, we here provide additional occurrence localities for the species across Sicily, and new insights into its ecology. Overall, 29 novel Sicilian records of P. zwierleini, scattered across 21 localities, were collected thus increasing its known Sicilian distribution area by 117%, and the number of localities by 110%. The species was found in a wide range of habitats such as open areas, woods, buildings, and caves, characterizing Plutonium zwierleini as a habitat generalist, whose fine ecological preferenda need to be further explored. Moreover, to explore the diet and behaviour of the species, some specimens were kept in captivity. The captive individuals fed mostly on dead or poorly mobile soft-bodied prey and inert food, without ever displaying predatory behaviour; this suggests that, contrarily to what is currently assumed, P. zwierleini might be a scavenger rather than a predator. The potential distribution of Plutonium zwierleini in Sicily was inferred based on georeferenced occurrence records and climatic variables. The implemented MaxEnt model forecasts the possible occurrence of P. zwierleini on the whole island, with the single exception of its south-easternmost part, possibly due to the local pattern of precipitation seasonality. We hope that the present work might pave the way for further surveys aimed at a better understanding of the ecology of Plutonium zwierleini and the collection of new data in the other regions inhabited by this secretive species. [ABSTRACT FROM AUTHOR]

The only Palearctic representative of the leech genus Placobdella Blanchard, 1893 is P. costata, an ectoparasite of freshwater turtles. To date, no conclusive evidence about the possible presence of coevolutionary patterns between this leech and its turtle hosts is available due to the paucity of DNA sequence data available for P. costata; moreover, comparative host data is also mostly lacking, making any inferences more difficult. The discovery of new populations of the species in northern Italy and Sicily allowed us to generate novel mitochondrial DNA sequences and to compare the topology of the resulting phylogenetic trees with the phylogeny of the turtle hosts occurring in the study area, i.e., Emys orbicularis and E. trinacris. The branching pattern of the phylogenetic tree for P. costata is not congruent with that of its turtle hosts, thus suggesting the lack of coevolutionary or cospeciation phenomena between these taxa. The lack of a coevolutionary pattern might be ascribed to the different dispersal ability of Placobdella costata and Emys spp. and to the host generality of the leech, as confirmed by the occurrence of P. costata on aquatic turtles belonging to the genus Mauremys in areas where Emys spp. are rare or absent. A single leech cytochrome c oxidase subunit 1 haplotype was found in each study region, and the overall nucleotide diversity was very low throughout the investigated distribution. This apparent lack of a clear phylogeographical pattern was unexpected in the P. costata populations occurring in the circum-Mediterranean areas, where the occurrence of high haplotype and nucleotide diversity is customary for most terrestrial and freshwater species. Based on the available data, we suggest a recent, post-glacial origin of the studied P. costata populations. [ABSTRACT FROM AUTHOR]

Evidence available for most inland water and terrestrial organisms highlights the significant role played by southern Italy, Sicily and the Maltese islands as refuges during Pleistocene climatic fluctuations. However, to date, the hypothesis that these areas may have acted as Pleistocene refugia for the freshwater crab Potamon fluviatile has not been explicitly tested, and a recent origin of local P. fluviatile populations was proposed on the basis of a small set of analysed molecular data. We have thus expanded the currently available data set on the population genetic structure of P. fluviatile through dedicated samplings in Sicily (Italy, 18 specimens), the Maltese Islands (Malta, 15 specimens) and the island of Corfu (Greece, seven specimens), with the explicit aim of testing the role of southern Italy, Sicily and the Maltese archipelago as refugia where early Pleistocene or pre-Quaternary populations of the freshwater crab could have persisted to date. Based on the analysis of both novel and published cytochrome c oxidase subunit I (COI) sequence data, we gathered evidence supporting a recent origin of the southern Italian, Sicilian and Maltese populations of Potamon fluviatile from the Balkans, thus rejecting the hypothesised Pleistocene persistence in the area of pre-existing local populations of the same species. [ABSTRACT FROM AUTHOR]

In the last few decades, findings of freshwater limpets belonging to the genus Ferrissia have been frequent and widely distributed throughout the Palaearctic and beyond. The widespread presence of a Nearctic alien taxon was proved, but no consensus was achieved about the possible existence of autochthonous Ferrissia taxa in the area, an occurrence which would be supported by the presence of gastropod fossils attributed to the genus throughout Eurasia and North Africa. In order to test the hypothesis of a possible persistence of autochthonous Ferrissia taxa in the Palaearctic to the present day, all the published data on the genetic diversity of Ferrissia populations occurring in the area were reviewed, expanding also the currently available dataset through dedicated sampling surveys in Italy, Malta and Spain. Here, based on currently published and novel large ribosomal subunit 16S rRNA (16S) and cytochrome oxidase sub-unit 1 (COI) sequences, the presence of the allochthonous Ferrissia californica in the whole Palaearctic was confirmed. Conversely, no evidence supporting the presence of autochthonous Ferrissia taxa was obtained. Ferrissia californica proved to be a highly invasive taxon (in spite of its extremely low genetic diversity) throughout the invaded regions, which is possibly related to the species' ability of asexual reproduction. Finally, the need to investigate the possible impact exerted by F. californica on the autochthonous Palaearctic biota is briefly stressed. [ABSTRACT FROM AUTHOR]

• Salaria marine and freshwater species belong to two independent clades. • Freshwater species are vicariant taxa with concordant mtDNA and nuDNA phylogenies. • Lack of reciprocal mtDNA monophyly is observed for the marine species of the genus. • The observed mito-nuclear discordance is due to introgressive hybridization. • Prudence is urged when implementing DNA barcoding approaches to fish identification. A comprehensive phylogeny of the genus Salaria based on mitochondrial and nuclear markers grouped the extant species of the genus in well-characterised marine and freshwater clades, thus rejecting the hypothesis of a polytypic origin of the freshwater Salaria populations and supporting the occurrence of a single invasion event of the inland waters by the genus. Based on both mitochondrial and nuclear DNA datasets, the Salaria species of the freshwater clade proved to be vicariant taxa originating from a common ancestor which could possibly spread throughout the circum-Mediterranean inland waters during the late Miocene Messinian salinity crisis, then experiencing a process of allopatric differentiation after the re-flooding of the Mediterranean basin. Within the marine clade, although the nuDNA datasets showed the existence of well-supported subclades in accordance to the morphological identification of the studied specimens, one of the two subclades obtained in the phylogenetic tree based on the mtDNA dataset included both S. basilisca and S. pavo specimens, thus failing to find the two species as reciprocally monophyletic. Such a mito-nuclear discordance is here ascribed to multiple mtDNA unidirectional introgression events from S. basilisca to S. pavo , and the molecular diversity pattern of the marine Salaria species is here ascribed to a Pleistocene speciation event nowadays partly concealed by the occurrence of introgressive hybridization phenomena between the two taxa. Our results urge for prudence when implementing DNA barcoding approaches since, in the presence of mito-nuclear discordance phenomena, single-marker mtDNA-only analyses might lead to significant misidentifications. [ABSTRACT FROM AUTHOR]