Jawed vertebrates rapidly eclipsed jawless fishes in species diversity after they appeared approximately 450 million years ago. Only two jawless clades comprising less than 1% of living vertebrate diversity have survived: the lampreys and hagfishes. Here, we present a new phylogeny and historical biogeographic reconstruction of lampreys that includes all living species. We show that whereas the early diversification of living lampreys tracks Pangaean fragmentation, lampreys rapidly diversified in the northern hemisphere during the mid-Cretaceous turnovers and directly after the Cretaceous-Paleogene mass extinction. These radiations mirrored concurrent adaptive radiations in other lineages of animals and plants and coincided with changes to lamprey ecology and feeding behavior. Our time-calibrated phylogeny suggests that 80% of living lamprey clades appeared in the last 20 million years of Earth history. The age of the lamprey common ancestor inferred by our phylogeny is markedly younger than the oldest fossil occurrences of stem-group lampreys during the initial dominance of jawless fishes in the early Paleozoic, indicating living lamprey biodiversity is the result of lineage diversification extending from the Cretaceous to present.

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Required software applications are RStudio and BEAST 2.6.6. suite.