Relict populations of Hyloniscus transsilvanicus and Ligidium germanicum in the Blahnita Plain, south-western Romania (Isopoda, Oniscidea)

In the Blahnita Plain of south-western Romania, two terrestrial isopod species, Hyloniscus transsilvanicus and Ligidium germanicum, are present, considered in the past to be restricted to high altitudes in this country. In this area H. transsilvanicus populates swamps and canals situated between 39 and 91 m a.s.l. L. germanicum was identified at the bank of a small stream at 45 m a.s.l. The possible explanations of the two species presence at such low altitudes are discussed.