A new species of ants, Dolichoderus jonasi sp. n., from a Late Eocene amber (Rovno and presumably Baltic ambers) of Europe is described from three workers and one male. The new species differs from all known fossil and recent species of the genus by the following set of characters: the presence of thorns on the pronotum, a head tapering to the back with pronounced occipital angles, a dimpled (with numerous pits) sculpture on the head and thorax, the presence of a ridge on the posterior edge of the main surface of the propodeum with a row of large setae, the presence of large straight setae on the body arranged in rows, high and somewhat narrowed to the apex petiole scale. The described species cannot be assigned to any of species groups (complexes) in the genus. The phylogenetic relationships of the new species with other species of the genus are discussed. Based on the studied morphological features, the species is closest to representatives of the debilis complex, widespread in South and Central America. However, it has significant differences and should be considered as the separate jonasi complex. We used computer microtomography methods to study structures inaccessible for optical microscopes and accurate measurements, which made it possible to characterize all diagnostic characters of the new species. Reconstructions of a worker and a male using 3D modeling are presented. The discovery of D. jonasi sp. n. in European Late Eocene amber is another possible evidence of relations between the faunas of Europe and the Americas in the past.