Diversity and distribution of freshwater amphipod species in Switzerland (Crustacea: Amphipoda).

Amphipods are key organisms in many freshwater systems and contribute substantially to the diversity and functioning of macroinvertebrate communities. Furthermore, they are commonly used as bioindicators and for ecotoxicological tests. For many areas, however, diversity and distribution of amphipods is inadequately known, which limits their use in ecological and ecotoxicological studies and handicaps conservation initiatives. We studied the diversity and distribution of amphipods in Switzerland (Central Europe), covering four major drainage basins, an altitudinal gradient of>2,500 m, and various habitats (rivers, streams, lakes and groundwater). We provide the first provisional checklist and detailed information on the distribution and diversity of all amphipod species from Switzerland. In total, we found 29 amphipod species. This includes 16 native and 13 non-native species, one of the latter (Orchestia cavimana) reported here for the first time for Switzerland. The diversity is compared to neighboring countries. We specifically discuss species of the genus Niphargus, which are often receiving less attention. We also found evidence of an even higher level of hidden diversity, and the potential occurrence of further cryptic species. This diversity reflects the biogeographic past of Switzerland, and suggests that amphipods are ideally suited to address questions on endemism and adaptive radiations, post-glaciation re-colonization and invasion dynamics as well as biodiversity-ecosystem functioning relationships in aquatic systems

Data from: Parallels between two geographically and ecologically disparate cave invasions by the same species, Asellus aquaticus (Isopoda, Crustacea)

Caves are long-known examples of evolutionary replications where similar morphologies (troglomorphies) evolve independently as the result of strong natural selection of the extreme environment. Recently, this paradigm has been challenged based on observations that troglomorphies are inconsistent across taxa and different subterranean habitats. We investigated the degree of replicated phenotypic change in two independent cave invasions by the freshwater isopod Asellus aquaticus; the first in a sulphidic aquifer in Romania, the second in a sinking river in the Dinaric Karst in Slovenia. Both ancestral surface populations still live alongside the subterranean ones. Phylogenetic analyses show independence of the two colonization events, and microsatellite analysis shows no evidence of ongoing genetic exchange between surface and subterranean ecomorphs. The overall morphology has changed dramatically at both sites (50 of 62 morphometric traits). The amount of phenotypic change did not reflect differences in genetic diversity between the two ancestral populations. Multivariate analyses revealed divergent evolution in caves, not parallel or convergent as predicted by the current paradigm. Still, 18 traits changed in a parallel fashion, including eye and pigment loss and antennal elongation. These changes might be a consequence of darkness as the only common ecological feature, because Romanian caves are chemoautotrophic and rich in food, whereas Slovenian caves are not. Overall, these results show that morphologically alike surface populations can diverge after invading different subterranean habitats, and that only about one-third of all changing traits behave as troglomorphies in the traditional sense

Genotypes of Asellus aquaticus on 8 microsatellite loci

Dataset contains genotypes of surface and subterranean ecomorph pairs of Asellus aquaticus from Slovenia and Romania. 324 individuals were genotyped on 8 microsatellite loci. Columns in the table: sampling site – site code on Figure 1 in the article; Voucher ID – sample name from the SubBioDatabase; alleles at each locus are recorded in separate columns. Missing data is recorded as "?"

Morphometric data ecomorphs Asellus aquaticus

Morphometric data: List of 60 traits used in morphometric analysis of surface and subterranean Asellus aquaticus ecomorphs from Slovenia and Romania. Means, standard deviations (SD) and standard errors (SE) of 60 morphometric traits (listed in Table A) in the surface and subterranean ecomorph pairs of Asellus aquaticus from Slovenia (PP/PR*) and Romania (MD/AW*). Asterisk (*) denotes the subterranean ecomorph relative to its ancestral surface form

Population genetics results

Population genetics analysis: number of alleles, observed and expected heterozygosity, tests of Hardy-Weinberg equilibrium for each locus separately and linkage disequilibrium. Included are also results from Structure analysis of the Romanian samples

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 February 2011–31 March 2011

This article documents the addition of 111 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acipenser oxyrinchus desotoi, Anopheles nuneztovari sensu lato, Asellus aquaticus, Calopteryx splendens, Calopteryx virgo, Centaurea aspera, Centaurea seridis, Chilina dombeyana, Proctoeces cf. lintoni and Pyrenophora teres f. teres