A new fossil myrmicine ant genus and species Lelejus venustusgen. et sp. nov., are described from late Eocene Rovno amber (Priabonian, 33.9–37.8 Ma). This genus differs from all extant and extinct Myrmicinae genera known from the late Eocene European ambers in the combination of morphological features, in particular: 13-segmented antennae with a very short scape and filiform funiculus; 3-segmented maxillary and 2-segmented labial palps; well-developed mandibles with dentate masticatory margin; scutum with broad notauli; forewings with closed cells 1+2r, 3r and mcu, the cell 3r of approximately the same length as cell 1+2r; free vein M branches off from RS approximately at the midlength between the junction of cross-vein 2r-rs with RS and vein m-cu; the cross-vein cu-a is located far from the base of wing, so the branch 1M+Cu is much longer than 2M+Cu. The taxonomic position of the described genus is discussed.