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Sampling-standardized origination and extinction rates in (A) eastern African Bovidae and (B) Turkana Basin large mammals. Older origination and younger extinction rates are increased by edge effects, and the oldest and youngest points, respectively, are omitted. Elevated turnover is recorded at 3.25–3.0 Ma (bovids) and 2.0–1.75 Ma (both). Turnover is low between 3 Ma and 2 Ma. (Error bars, 1 SD of 100 subsampling trials in each direction.)
