Diversity of dictyostelid social amoebae in high latitude habitats of Northern Sweden

The dictyostelid social amoebae (Dictyostelia) occur in terrestrial habitats worldwide. It has been observed previously that their diversity decreases with increasing latitude and altitude. Here we look at dictyostelid diversity in the high latitude habitats of Northern Sweden. Dictyostelids were recovered from soil samples using traditional plating methods and then identified using morphological characters and molecular sequence (small subunit ribosomal RNA) data. In total, nine species were recovered, including two new species, described herein as Dictyostelium barbibulus and Polysphondylium fuscans . The species diversity found here is discussed in relation to previous findings in the area as well as other high-latitude studies, and biogeographical patterns are examined. The total number of species found in Northern Sweden is lower than the numbers recorded for regions further south in Europe, a finding consistent with a latitudinal gradient of species diversity. Our findings highlight the benefit of using molecular data for accurate species identification in Dictyostelia and the need for a continued sampling effort to better understand their diversity and distribution, especially in high latitude habitats.