New species of the extinct ant genus Stigmomyrmex Mayr and designation of the neotype of Stiphromyrmex robustus (Mayr) (Hymenoptera: Formicidae: Myrmicinae)

The extinct ant genera Stigmomyrmex Mayr and Stiphromyrmex Wheeler (subfamily Myrmicinae) were described from the Baltic amber (Late Eocene, Priabonian, ca. 34-38 Ma). A new species, Stigmomyrmex rugulosus sp. nov., is described from the Baltic and Bitterfeld ambers, and a neotype of Stiphromyrmex robustus (Mayr) is designated. Additionally, we found from the Bitterfeld amber three more specimens of S. venustus Mayr, previously the only known species of the genus. S. rugulosus well differs from S. venustus by the presence of longitudinal rugulosity on the head dorsum, mesosoma and waist, and by the presence of numerous suberect hairs on the legs.