First record of the alien spider species Mermessus trilobatus (Araneae: Linyphiidae) in Ukraine.
Mermessus trilobatus (Emerton, 1882) is recorded for the first time in Ukraine. Its presence represents the easternmost boundary of this species in Europe. One male was found in the glacial cirque of the mountain massif Svydivets' in the Ukrainian Carpathians at an altitude of 1495 m. The locality is a mountain stream, the banks of which have been moderately grazed by sheep. Information on the distribution of this species in Central and Eastern Europe is given.