Genomic evidence reveals a radiation of placental mammals uninterrupted by the KPg boundary

We produced a genome-scale dataset from representatives of all placental mammal orders to infer diversification timing relative to the Cretaceous-Paleogene (KPg) boundary. Our sensitivity analyses show that divergence time estimates within placentals are considerably biased by the specific way in which a given dataset is processed. We examined the performance of various dating approaches using a comprehensive scheme of likelihood analyses and computational simulations, allowing us to identify the optimal molecular clock parameters, gene sets, and gene partitioning schemes for reliable dating. Based on the optimal methodology, we present a hypothesis of mammalian divergence timing that is more consistent with the fossil record than previous molecular clock reconstructions, suggesting that placental mammals underwent a continuous radiation across the KPg boundary.