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With the biodiversity crisis continuing unchecked, we need to establish levels and drivers of extinction risk to effectively allocate conservation resources and develop targeted actions. Given that threat appears particularly high in freshwaters, we assessed the extinction risk of 1,500 randomly selected freshwater molluscs using the IUCN Red List Categories and Criteria, as part of the Sampled Red List Index project. We show that close to one third of species in our sample are estimated to be threatened with extinction, with highest levels of threat in the Palearctic, Australasia and Nearctic and among gastropods. Threat levels were higher in lotic than lentic systems. Twenty-seven species were classified as Extinct (eight bivalves and 19 gastropods), mostly from the Nearctic realm and lotic systems. Pollution and the modification of natural systems (e.g. through damming and water abstraction) were the most frequently reported threats to freshwater molluscs, with some regional variation. Given that we found little spatial congruence between species richness patterns of freshwater molluscs and other freshwater taxa, new additional conservation priority areas emerge from our study. We discuss the implications of our findings for freshwater mollusc conservation and important next steps to estimate trends in freshwater mollusc extinction risk over time.

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Species delimitation for cryptic species complexes: case study of Pyramidula (Gastropoda, Pulmonata). -Zoologica Scripta, 46, 55-72. Species discovery and validation methods were used to delimit the species of a cryptic species complex. Species boundaries were inferred from multiple lines of evidence arising from mitochondrial and nuclear DNA sequencing and ecological niche modelling. Phylogenetic relationships among species were assessed by Bayesian inference and maximum-likelihood procedures. The approach was applied to the terrestrial gastropod genus Pyramidula. By examining 211 specimens collected from the Western Palaearctic region, we here identified nine putative species for this region. So far, descriptions of the morphospecies of this genus had been based exclusively on shell characters. Hence, we also studied the variation of shell characters to assess their utility to differentiate the species defined and to examine whether shell shape in Pyramidula is influenced by environmental factors. Our findings indicate that although shell characters serve to discriminate between some putative species, they are not sufficient as unique taxonomic characters and other lines of evidence are needed. According to our ecological niche modelling results, shell shape may be influenced by environmental factors.

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Taxonomic clarification of three taxa of Iberian geomitrids, Helix montserratensis Hidalgo, 1870, and subspecies (Gastropoda, Pulmonata), based on morpho-anatomical data.-Helix montserratensis (currently Xerocrassa montserratensis) is an Iberian geomitrid described by Hidalgo in 1870 from Montserrat (Barcelona, Spain). Two very similar taxa were described as varieties of this taxon based only on conchological characters: Helix montserratensis betulonensis and a less known taxon, Helix montserratensis delicatula. These varieties, especially betulonensis, were considered for a long time as subspecies of X. montserratensis, although some authors upgraded them to the rank of species based on anatomical data of the reproductive system in a few specimens. We review the type specimens and other samples of the three taxa collected at several localities where the three referred taxa are considered present. The morpho-anatomical characteristics of the shell and the reproductive system were studied in detail. The results allow us to clarify the taxonomic status of X. betulonensis and X. m. delicatula as X. montserratensis, indicating they should be considered junior synonyms of this species. Finally, the shell is redescribed and a map is provided showing the geographical distribution of X. montserratensis.