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Ancestral estimates for the TI as a function of the crown age (My) of the lineage. Partitions at the top delineate geological epochs [lower (Klow) and upper (Kup) Cretaceous, Paleocene (Pε), Eocene (EO), Oligocene (OG), Miocene (MI), and Pliocene (PO)], whereas the gray bands represent cool periods in the paleoclimate record (49).
