An Eocene army ant Author Sosiak, Christine E. Federated Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ 07102, USA ces43@njit.edu Author Borowiec, Marek L. Department of Agricultural Biology and C. P. Gillette Museum of Arthropod Diversity, Colorado State University, CO 80523, USA Author Barden, Phillip Federated Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ 07102, USA & Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA text Biology Letters 2022 20220398 2022-11-23 18 11 1 5 http://dx.doi.org/10.1098/rsbl.2022.0398 journal article 10.1098/rsbl.2022.0398 Genus Dissimulodorylus Sosiak, Borowiec, & Barden gen. nov. Diagnosis : Worker. Dissimulodorylus can be distinguished from most doryline genera by the combination of lack of eyes, complete pronotomesopleural suture, propodeal spiracle positioned high on the propodeum and single waist segment. These characteristics make it most like Dorylus , which can be differentiated by the presence of an impressed pygidial field and lack of fused, dorsoventrally flat, overhanging and triangularly shaped frontal lobes characteristic for this fossil. Type species : Dissimulodorylus perseus sp. nov. Etymology : From Latin ‘dissimulo’ meaning to conceal, hide or disregard, in reference to the type specimen eluding description for likely 80 years.