A long-expected finding: the first record of the isopod Eluma caelatum (Miers, 1877) from Belgium (Crustacea: Isopoda: Armadillidiidae)

Since the discovery of Eluma caelatum (Miers, 1877) in the Netherlands close to the Belgium boarder in the mid 1990’s, various attempts have been made to find this isopod species in Belgium. However, these attempts have been unsuccessful until a joint excursion of Belgian and Dutch isopod researchers searched for this enigmatic species once more in autumn 2016. They discovered the first Belgian specimens of E. caelatum at the nature reserve “Zwin” near Knokke in West-Vlaanderen. One month later, another population was found near Sint-Laureins in Oost-Vlaanderen, also close to the Dutch border. Possibly E. caelatum colonised Belgium from the Netherlands since there are no connections with southern populations in France. In Belgium and The Netherlands the species is bound to coastal areas with a synantropic character, like levees of dikes and ditches while it is more of a forest species in southern Europe. Therefore, it is unclear if the species is an accidental import from the south or if the species is native at the edge of its distribution range.