Testate Amoebae in Historical parks of Potsdam, Germany

•First study of shell-bearing (testate) amoebae conducted in historical parks of Potsdam, Germany.•76 species and subspecies of testate amoebae were identified (in 32 soil samples)•Maximum species diversity was found near deciduous trees and in meadows but habitats near conifers were less diverse.•Renewed finding of a species of the newly described genus FrenopyxisBobrov &Mazei 2020.•Historic urban parks offer opportunities to unearth new geographical records. To explore the potential of urban settings as habitats for testate amoebae, five historical parks in Potsdam (Germany) were sampled at different sites. A total of 32 sampling sites was chosen in proximity to deciduous (Acer, Castanea, Fagus, Tilia, Platanus, Quercus) and coniferous (Fraxinus, Picea, Pinus, Tsuga) trees. Meadows and creeks were also sampled. The overall taxonomic record comprises 76 species and sub-species. High species numbers of >20 per sample were found in meadows and below Fagus, Tilia, and Quercus trees. The species richness per park ranges from 33 to 46 taxa. Most species belong to the eurybiontic ecological group, although litter-inhabiting and hygrophilic and hydrophilic species were also present. Common species found in more than 50% of all samples (superdominants) belong to the genera Centropyxis, Cyclopyxis, Euglypha, and Trinema. Interestingly, the rare Frenopyxis stierlitzi which inhabits tree hollows was found as a recently described species in a new genus FrenopyxisBobrov&Mazei2020 in the Babelsberg Park. The studied testate amoebae are characterized by a high degree of morphological and morphometric plasticity. Therefore, the study of testate amoebae in urban settings will reveal new insights into their ecology and enhance the definition of morphometric variability for single species.