The oldest Cenozoic ant fossil: † Tyrannomecia gen. nov. (Formicidae: Myrmeciinae) from the Palaeocene Menat Formation (France) Author Jouault, Corentin 0000-0002-3680-5172 Institut de Systématique, Évolution, Biodiversité (ISYEB) Muséum national d’Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, CP 50, 57 rue Cuvier 75005, Paris, France & Univ. Rennes, CNRS, Géosciences Rennes, UMR 6118, F- 35000, Rennes, France & CNRS, UMR 5554 Institut des Sciences de l’Évolution de Montpellier, Place Eugène Bataillon, 34095, Montpellier, France jouaultc0@gmail.com Author Nel, André 0000-0002-4241-7651 Institut de Systématique, Évolution, Biodiversité (ISYEB) Muséum national d’Histoire naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, CP 50, 57 rue Cuvier 75005, Paris, France text Historical Biology 2021 2021-12-12 34 11 2241 2248 http://dx.doi.org/10.1080/08912963.2021.2010192 journal article 10.1080/08912963.2021.2010192 616f0513-90fe-4370-bb63-c7f70a876f26 1029-2381 5838068 Tyrannomecia gen. nov . urn:lsid:zoobank.org:act:C8DFF49D-104C-4066-8066-60EE65 79BF56 Figure 1. Tyrannomecia inopinata gen. et sp. nov. , holotype MNHN.FA71374. Photographs. (a) habitus on part; (b) habitus on counterpart. Scale bars = 2 mm. Figure 2. Tyrannomecia inopinata gen. et sp. nov. , holotype MNHN.FA71374. Photographs. (a) head; (b) petiolar region. Scale bars = 2 mm (a), 1 mm (b). Type species Tyrannomecia inopinata sp. nov. Diagnosis Worker. Head slightly longer than wide (ca. 1.20 ×); eyes large (0.26 × head length), located anteriad head mid-length, near epistomal (clypeal) margin; mandibles elongate (not triangular), shorter than head (ca. 0.61 × as long as head length), not broadly crossing apically ( sensu Bolton 2003 ), with small tubercles/teeth along masticatory margin (as in Nothomyrmecia ); propodeum smooth (without propodeal tooth); petiole short, dorsal surface broadly rounded, posterior surface with a conspicuous tooth; sternite of AIII without visible prora (if present, not in form of a longitudinal keel); AIII and AIV separated by a constriction. Etymology The genus name is a combination of the Latin word tyrannus , from the ancient Greek τύραννο) meaning absolute ruler, and the suffix ‘mecia’, often used for ant genus names. Gender feminine.