Chthonius marusiki sp. nov. – the first pseudoscorpion of the family Chthoniidae Daday, 1889 (Arachnida, Pseudoscorpiones) from the late Eocene Rovno amber

A new species of chthonioid pseudoscorpion is described from Eocene Rovno amber (Ukraine), including a detailed diagnosis and illustrations: Chthonius marusiki sp. nov. (Arachnida, Pseudoscorpiones) is the first valid species of the family Chthoniidae from Rovno amber. Diagnostic, biogeographic, paleohabitat and ecological features of this new species are presented and discussed, and are compared to the related extinct and extant species of this genus.