Soil Testate Amoebae from some Heritage Sites of Japan, with a description of a new Centropyxis species (Amoebozoa, Excentrostoma)

抄録

Soil samples from one UNESCO World Heritage Site (Iwami Ginzan, a historic silver mine, Ohta, Shimane Prefecture) and three National Heritage Sites (Iwaki, Fukushima Prefecture) of Japan revealed 108 taxa of testate amoebae (morphospecies and morphotypes, incl. numerous “singletons”), of which cosmopolitan species, e.g., Centropyxis elongata, Euglypha rotunda, Phryganella acropodia, Plagiopyxis declivis, Trinema enchelys, and T. lineare occurred most frequently. However, some taxa such as Gibbocarina galeata, Planhoogenraadia spp., Trinema lenticularis, or Zivkovicia compressoidea have a geographically restricted distribution and/or are considered as rare. In this study, we described a new species, Centropyxis todorovi sp. nov., from Iwami Ginzan. Additionally, we suggested transferring Centropxis capucina and Centropxis pseudodeflandriana to genus Hoogenraadia and Centropxis laevigata to genus Frenopyxis.

From the historic Iwami Ginzan silver mine, soil samples were analysed for total and bio-available heavy metals (Ag, Co, Cu, Pb, and Zn). Due to the silver extraction methodology, high total concentrations of Pb and Zn had been detected. However, the bioavailable concentrations were very low. There was no relationship between the taxa numbers of testate amoebae and heavy metal concentrations.

It will be expected that further research will discover considerably more new or unrecorded testate amoebae, raising the awareness of the public, as well as of the scientific community, on these unique Heritage Sites of Japan.