Revising dating estimates and the antiquity of eusociality in termites using the fossilized birth-death process

International audienceDeciphering the timing and tempo of lineage diversification of organisms has greatly benefited from advances in Bayesian phylogenetic analyses using morphological data. Those advances, however, have not been used for termites despite a rich fossil record. Here, we estimate divergence times for living and fossil termites using the fossilized birth–death (FBD) process on a previously published morphological matrix expanded with two new fossils that we describe (see Appendices 1 & 2). Those fossils, based on soldier specimens, are the ‘mid’-Cretaceous mastotermitid Milesitermesengeligen. et sp. nov., and the Middle Eocene Reticulitermesgrimaldiisp. nov. The latter is the oldest occurrence of a Rhinotermitidae soldier and the first termite soldier described from Baltic amber. Our dating estimates provide new stem- and crown-ages for termites, suggesting older ages than previously thought for several lineages. Importantly, crown-Isoptera—and therefore eusociality—may have arisen ~200 Ma. We conclude with further directions to keep improving our understanding of the timing of differentiation in termites.Page 2 of 77Systematic Entomolog