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Marine species exhibiting wide distributional ranges are frequently subdivided into discrete genetic units over limited spatial scales. This is often due to specific life-history traits or oceanographic barriers that prevent gene flow. Fine-scale sampling studies revealed distinct phylogeographic patterns in the northeastern Atlantic and the Mediterranean, ranging from panmixia to noticeable population genetic structure. Here, we used mitochondrial sequence data to analyse connectivity in the bogue Boops boops throughout most of its widespread distribution. Our results identified the existence of three clades, one comprising specimens from the Azores and eastern Atlantic/Mediterranean, another with individuals from the Canary Islands, Madeira and Cape Verde archipelagos, and the third with samples from Mauritania only. One of the branches of the northern subtropical gyre (Azores Current) that drifts towards the Gulf of Cádiz promotes a closer connection between the Azores, southern Portugal and the Mediterranean B. boops populations. The Almería-Oran Front, widely recognised as an oceanographic barrier for many organisms to cross the Atlantic-Mediterranean divide, does not seem to affect the dispersal of this benthopelagic species. The southward movement of the Cape Verde Frontal Zone during the winter, combined with the relatively short duration of the pelagic larval stage of B. boops, may be potential factors for preventing the connectivity between the Atlantic oceanic archipelagos and Mauritania shaping the genetic signature of this species. [ABSTRACT FROM AUTHOR]

In brown trout, instances of genetic homogenization after introducing hatchery-reared allochthonous Atlantic strains are well documented. Therefore, mitigation-driven translocation with autochthonous lineages is gaining support. However, when the origin of local donor populations is not clear they should be genetically characterized prior to translocation. Here we present a case study from the Vlasina Plateau in Southeast Serbia, where two drainages, Danube and Aegean, are adjoining. The status of Danubian and Aegean brown trout populations was investigated with respect to inter-relationship and genetic admixture using mtDNA and microsatellite loci. Results revealed a complex genetic structure and demonstrated different levels of introgressive hybridization from the Aegean populations (which belong to the Adriatic evolutionary lineage) into the Danubian populations as a direct consequence of human mediated translocations. While most introgressed Danubian locations showed low to intermediate proportions of allochtonous genes this was not the case with the upper Jerma location, where all individuals were characterized as pure Adriatic lineage of brown trout. Contrarily, Aegean locations from the Plateau are inhabited by pure Adriatic brown trout. Finally, our analysis clearly demonstrates that the biological invasion followed a stepping-stone scenario via the upper Jerma, which served as a local donor population for supplementing other Danubian populations, and excludes the possibility of brown trout invading through physical connections between the two drainages that were established because of Vlasina hydroelectric power plants. Furthermore, evidence of increased stocking in the wider region is additionally supported by the detection of low level introgression with the domesticated Atlantic brown trout. [ABSTRACT FROM AUTHOR]

Gobius xoriguer sp. nov., a new ofshore species of goby (Teleostei: Gobiidae: Gobiinae) is described based on three specimens collected in 2010, 2012 and 2018 in the western Mediterranean, off Menorca (Spain), in the Gulf of Lion and off Corsica (France), at 51–104 m depth on coralline algae sea bed. It is easily distinguishable from its Atlantic-Mediterranean congeners by the combination of the following characters: large eyes, ~27–28% of head length; anterior nostril with a small triangular process; 14 soft rays on D2, 13 soft rays on A; enlarged first dorsal fin rays (adult males), with third D1 spine the longest, 23–27 % SL; uppermost P fin rays not free from membrane; long V-shape pelvic fins with vestigial frenum; 50–51 scales on LL; head oculoscapular canal with pores σ, λ, κ, ω, α, β, ρ, ρ1, ρ2, and preopercular canal with pores γ, δ, ε present; row x1 ending anteriorly behind pore β; a groove section between pore ρ and ρ1; suborbital row d discontinuous with large gap below suborbital rows 3 and 4; rows o separated; seven enlarged orange blotches on body side; white dotes on cheek and opercle on an orange background. With a known maximum size of 64 mm TL, it is among the smaller species of Gobius. Bayesian inference and Maximum likelihood phylogenetic tree topologies based on mitochondrial DNA COI sequences (barcoding region), including most Atlantic-Mediterranean Gobius species, support Gobius gasteveni Miller 1974 as the closest relative to Gobius xoriguer sp. nov. These sister species exhibit a high genetic divergence of 9.5% (uncorrected p-distance). [ABSTRACT FROM AUTHOR]

It was reported that the complex geological history of the southern Balkans caused diversification of terrestrial species. On the other hand, knowledge of the evolutionary history of freshwater biota is scarce. In order to contribute to an understanding of the historical biogeography of the region's freshwaters, as well as to describe intraspecific diversity and structure of a species distributed in the Ionian Ecoregion, we have analysed the population genetic structure and evolutionary history of Telestes pleurobipunctatus. Analyses were based on the mitochondrial gene for cytochrome b from samples covering the whole distribution range of this species. A high level of intraspecific structuring was revealed inside T. pleurobipunctatus. Its evolutionary history corroborates the complexity of historical geologic events in the area. Telestes pleurobipunctatus comprises two main clades (northern and southern), which have been separated from each other for about seven million years and that are further divided. The Louros and Arachthos Rivers were denoted as ancestral geographic ranges of the northern clade. The distribution range of the ancestor of the southern clade seems to comprise rivers flowing into the Patraikos Gulf. Structures within the two main clades, as well as timing of diversification events are different, implying separate evolutionary courses. [ABSTRACT FROM AUTHOR]

Until recently all the Alburnoides populations of the Macedonia-Thessaly and Western Aegean ecoregions were considered as Alburnoides bipunctatus thessalicus Stephanidis, 1950. Here a new species of spirlin, Alburnoides economoui, is described from the Spercheios River (Fthiotida Prefecture). It is distinguished from all other congeners in Greek river basins and the Danube and Elbe drainages by the combination of the following characters: a very sharp ventral keel, scaleless or with 1-2 scales; 12½-14½ branched anal-fin rays; 42-47 + 1-3 pored lateral line scales; 19-25 pre-dorsal scales; snout conical, slightly pointed; snout length shorter than eye diameter; pelvic-fin origin about midway between pectoral-fin and anal-fin origins or slightly closer to anal-fin origin. The name Alburnoides thessalicus is now restricted to the populations from the Pinios, Aliakmon and Axios/Vardar rivers. A redescription and designation of neotype for Alburnoides thessalicus is provided. The species can be distinguished from all other congeners in Greek river basins and the Danube and Elbe basins by the presence of a sharp ventral keel in only 2/3 of its length, variably scaled with modally 4-6 scales; usually 12½ branched anal-fin rays; 44-50 + 1-2 pored lateral line scales; 24-31 pre-dorsal scales; snout stout, slightly to clearly rounded; snout length about equivalent to the eye diameter; pelvic-fin origin closer to anal-fin origin than to pectoralfin. Despite similar morphological characters when compared to other European Alburnoides species, A. economoui differs remarkably genetically from all other studied Alburnoides species. The interspecific genetic divergence based on cytochrome b nucleotide sequences ranges from 7.3 to 8.8% (uncorrected p-distance). [ABSTRACT FROM AUTHOR]

The main aims of this study were to determine whether reservoir sediments provide good temporal records of atmospherically deposited spheroidal carbonaceous particles (SCPs), and to examine their spatial distribution within the reservoir. SCPs are produced solely by fossil-fuel burning and are good indicators of the extent of industrial pollution. The site chosen for the study was Drásov Reservoir in the Czech Republic. Sediment cores were taken along two transects within the reservoir. The results suggest that wind- and inlet-induced currents have an important influence on both SCP and sediment distribution in the reservoir, and that the distribution of SCPs is different to that of sediments. The SCP records were most reliable in the down-wind area of the reservoir, and although most detailed SCP record was contained in a deep-water core near the dam, records in shallower-water cores from the down-wind side of the reservoir were also good. The correlation between SCP accumulation rates and solid emissions from local sources was very good (Spearman R=0.867, p=0.001).% [ABSTRACT FROM AUTHOR]

Parasites exhibiting a high degree of host specificity are expected to be intimately associated with their hosts. Therefore, the evolution of host-specific parasites is at least partially shaped by the evolutionary history and distribution of such hosts. Gill ectoparasites of Dactylogyrus (Monogenea) are specific to cyprinid fish. In the present study, we investigated the evolutionary history of 47 Dactylogyrus species from the Balkan Peninsula, the Mediteranean region exhibiting the highest cyprinid diversity in Europe, and from central European cyprinids. Phylogenetic analyses revealed four well-supported clades of endemic and non-endemic Dactylogyrus spp. with four basal taxa. Endemic cyprinids with a limited distribution range were parasitized by endemic Dactylogyrus species, but some of them shared several Dactylogyrus species with central European cyprinids. Species delimitation analyses based on molecular data suggest that Dactylogyrus diversity is higher than that defined from morphology. Some endemic cyprinid species harboured Dactylogyrus species of different origins, this probably resulting from multiple host switching. Our results support the view that the evolution of Dactylogyrus in the Balkans has been influenced not only by the historical dispersion and distribution of their cyprinid hosts, but also by recent contacts of non-native cyprinid species with endemic cyprinid fauna in this region. [ABSTRACT FROM AUTHOR]