Résumé
A new genus and species of myrmeciine ants, also called bulldog ants, is described and illustrated from the Palaeocene of Menat (France) as Tyrannomecia inopinata gen. et sp. nov. This new taxon represents the oldest representative of the subfamily and provides the oldest calibration point for the total clade Myrmeciinae. It shows the apomorphic characters used to define the Myrmeciinae: mandibles elongate such that their length is three-quarters or more of head length, third abdominal segment (AIII) substantially smaller than the fourth abdominal segment (AIV), and with its height distinctly less than that of the fourth one. This new genus is easily differentiated from all the other myrmeciine ants owing to its petiole with a conspicuous tooth located dorsally on the posterior declivity, and is considered to belong to the stem-Myrmeciinae. Aside from the calibration aspects, this new taxon, possessing a hunter morphology, is used to discuss implications for the recovery of ants after the K/Pg.