ABSTRACT1. The duck mussel, Anodonta anatina, has been described as abundant and widespread in Europe. However, it is listed as near threatened or threatened in several countries owing to severe declines in abundance and/or spatial distribution.2. Despite its potential ecological importance and conservation status almost nothing is known regarding its genetic diversity.3. As a preliminary analysis, variation within the cytochrome oxidase 1 mitochondrial gene was determined from European specimens from Portugal in the south west, to Ukraine in the east, and Sweden in the north.4. Three major mtDNA clades were retrieved: clade 1 includes all the individuals from Iberia, except those from the Ebro basin; clade 2 includes all the European non-Iberian and non-Italian samples; and clade 3 includes all the individuals from Italy and from the Ebro basin. AMOVA analysis revealed significant genetic differences among the three clades. Within each of the major clades, several geographically related haplogroups were also retrieved, especially in Iberia, where four genetically distinct groups (North-West, South-Central, South-West and Ebro) were revealed.5. Given the evidence of regional declines of A. anatina in Europe, the confirmation of geographically distinct genotypes indicates a need for the development of management strategies directed towards the conservation of localized populations.

An important population of the critically endangered pearl mussel Margaritifera margaritifera (Linnaeus, 1758) was surveyed at the edge of its southern distribution (River Paiva, Portugal). Although an earlier study suggested that this population had a very low number of individuals (\500), a narrow distribution, and was mainly comprised by old specimens our data contradict these findings. Our assessment estimated a population with probably more than 5,000 individuals distributed across 80 km of the river length. From the 32 sites surveyed, 19 contained M. margaritifera with higher abundances verified in the middle and upper parts of the river (a maximum of 78 ind. per 100 m of river stretch was recorded). The pearl mussels showed a clear preference for areas near the banks, in shallow water, sandier and gravel sediments, and a high degree of riparian vegetation cover. The population structure was skewed with a very high percentage of large (and old) animals but 3.7 % of the individuals collected were juveniles (\60 mm in length); therefore, this population can be considered functional. Environmental characterization indicated that this river is still in excellent or good condition although some areas showed deterioration due to discharge of domestic effluents. The main conservation requirements of M. margaritifera in the River Paiva include maintaining the water quality (and if possible stopping the discharge of domestic effluents), increasing riparian vegetation cover, removing several weirs to increase connectivity, and increasing trout density.

a b s t r a c tThe Potomida genus (Bivalvia, Unionida) has a Circum-Mediterranean distribution and like other freshwater mussel species, its populations have suffered dramatic declines. Although this genus is currently considered as monotypic, it has a long history of taxonomic revisions and presently many aspects of its systematics and evolutionary history are unclear. We sampled a total of 323 individuals from 39 different sites across the Potomida genus distribution, and sequenced two mitochondrial (16S rDNA and Cytochrome c Oxidase Subunit I) and one nuclear (28S rDNA) genes to clarify its phylogeny and phylogeographic history. Our results show that the genus includes two well-supported clades, one comprising solely the western Mediterranean species Potomida littoralis, and the other including two eastern Mediterranean species, the Greek endemic P. acarnanica and the Anatolian and Middle Eastern P. semirugata. We suggest that Potomida started radiating during the upper Miocene, and that both vicariance and dispersal events shaped the diversification and distribution of the genus along the Mediterranean region. P. littoralis is further divided in two mitochondrial lineages, one restricted to Europe and the other occurring mostly in North Africa. Moreover, some European basins present both lineages in sympatry. The conservation status of the three recognized species should be reevaluated, particularly P. acarnanica, since it is restricted to two Greek river basins presenting a high risk of extinction. Overall, our results clarify some important gaps in knowledge concerning the phylogeny, phylogeography and evolution of the Potomida genus in the Mediterranean region with important taxonomical, ecological and conservational implications.

ABSTRACT1. The Unionidae are among the most endangered fauna in the world and globally in decline. They are particularly vulnerable to habitat loss and fragmentation, susceptible to flow, pollution and climatic disturbances and introduction of invasive species. Despite their well-recognized ecological and conservation importance, there is a surprising lack of genomic resources currently available for European species.2. The aim of this study was to develop and characterize microsatellites for the near threatened freshwater mussel, Potomida littoralis using 454 sequencing.3. In order to improve genotyping throughput as well as cost-effectiveness, two multiplex-PCR reactions were designed to amplify 16 new loci. All the new 16 microsatellites were successfully combined in two multiplexed PCR with the number of alleles ranging from 2 to 25 per locus (with a mean of 10), confirming the utility of the new markers.4. The new genetic markers can therefore be used for studying the population genetic structure and evolution of this species, e.g. to examine current levels of genetic variability within and between populations and thus to contribute to conservation and management.