Abstract
An unusual new omaliine species, Anthobium alekseevi sp. nov., is described and illustrated from Eocene Baltic amber, tentatively placed in the megadiverse genus Anthobium Leach, 1819. A new monotypic species-group is established. The new species can easily be distinguished from other species of the genus by the larger body, shape of the subrectangular pronotum, and the presence of a median carina on the prosternum and large, subtriangular tooth on the inner side of each mesotibia, likely exhibiting a peculiar sexual dimorphism in the male. Based on the study of the specimen with support of microtomographic images, a brief comparative analysis of a new species with described extant species of Anthobium is provided.