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Ruditapes decussatus (Linnaeus, 1758) (Veneridae) is an Atlanto-Mediterranean bivalve whose populations have experienced reductions and, in some instances, hybridisation with allochthonous R. philippinarum. Acquisition of additional genetic knowledge concerning the present R. decussatus populations is essential to address adequate conservation plans for this species. For this purpose, we analysed a portion of the mtDNA cytochrome c oxidase subunit I (COI) region in populations from the western Mediterranean, where this species represents a harvested fishery resource. Our analyses revealed an overall lack of genetic structure within the western Mediterranean area, and the occurrence of mtDNA substructuring between the Aegean and Marmara seas and the remaining populations from the whole Mediterranean basin and the South European Atlantic coast. The results obtained for populations from Sardinia, where extensive restocking programmes have not been reported and where R. philippinarum is rare and localised, suggest that intensive harvesting and potential dispersal alone may have been able to shape the genetic variation identified in the local R. decussatus populations. [ABSTRACT FROM AUTHOR]

Esox cisalpinus(Teleostea: Esocidae) (syn.Esox flaviae) is an Italian freshwater autochthonous fish, whose originary range is limited to the Northern and Central Italy. However, this species has historically been introduced in several areas of Southern Italy, mainly for recreational purposes. In this paper we report the first record ofE. cisalpinuson the Sardinia island (Western Mediterranean, Italy), where the species has been recently introduced at least in one lake. The species identification and the population dynamics analysis were performed using mitochondrial markers. The level of genetic variability, compared to those of other peninsular populations ofE. cisalpinus, was surprisingly high, and several never-before-described haplotypes were found. A total of 10 mtDNA haplotypes were found. Demographic analysis is suggestive of a population expansion. We hypothesise thatE. cisalpinushas been introduced in the Sardinian lake by the releasing of a conspicuous number of individuals. Given the conservational and recreational interest thatE. cisalpinusarouses, it would be advisable that Sardinian government focuses in the near future also on management measures of its Sardinian population. [ABSTRACT FROM AUTHOR]

The Mediterranean Lessepsian migrations excite the interest of biologists who are devoted to inferring the effects of selection on the genetic structure of immigrants. The bluespotted cornetfishFistularia commersoniiis an Indo-Pacific species that was first recorded in the Levantine cost of Mediterranean, and within a few years, it rapidly expanded throughout the entire basin. Studies on its genetic variability, performed via mitochondrial sequencing of the Mediterranean specimens, suggest that a limited number of mitochondrial lineages passed through the Suez Canal. However, nuclear markers provide a scenario, with a high genetic variability among the MediterraneanF. commersoniimigrants, along with the occurrence of haplotype sharing between the Mediterranean and the Red Sea. The aim of this study was to enlarge the number of Mediterranean sites in order to evaluate if the rapid expansion and different patterns of spread ofF. commersoniiin the basin could have led to a genetic structuring. The analysis was carried out by sequencing mitochondrial D-loop I in individuals from Sardinia, Sicily, Tunisia, Lampedusa, Libya and Lebanon. Sequences available from previous studies were included in the data set, allowing us to obtain a data set that likely represents the entire distribution range of the species. Results suggest the possible occurrence of two mitochondrial lineages involved in the Mediterranean invasion ofF. commersonii, a bottleneck may have caused a loss in the genetic variation, leading to the fixation of specific lineages as an adaptive response to the new environmental conditions. [ABSTRACT FROM AUTHOR]

Patella ulyssiponensis s.l. is widely distributed in the Mediterranean as well as in the north-eastern Atlantic, from southern Norway to north-western Africa, including Macaronesia. Throughout its range, P. ulyssiponensis s.l. shows a high degree of variability in the shape and colour pattern of the shell and in the colour pattern of the foot. In addition, the species demonstrates widely overlapping morphological parameters with the coexisting P. caerulea (in the Mediterranean), P. vulgata (in north-eastern Atlantic) and P. candei (in the Macaronesian islands). Thus P. ulyssiponensis s.l. identification proves to be difficult. So far, method to unequivocally identify uncertain specimens of P. ulyssiponensis s.l. from the coexisting species was using a molecular taxonomy approach based on the Cytochrome c Oxidase subunit I (COI) sequences analysis. The aim of the present study was to identify specific PCR-RFLP (Restriction Fragment Length Polymorphism PCR-based) markers on the COI sequences which could be used as an alternative and fast diagnostic tool for the discrimination of P. ulyssiponensis s.l. from P. caerulea, P. vulgata and P. candei, when the morphology of the coexisting individuals provided equivocal information. First, we sampled 65 Patella spp. and classified these by means of the COI sequencing. Then, we selected the TaqI endonuclease for the specific RFLP reaction, which produced a combination of RFLP electrophoretic bands, allowing an unequivocal identification of the individuals of P. ulyssiponensis s.l. [ABSTRACT FROM PUBLISHER]