Fig. 3.

Episodic incompleteness of the fossil record can cause a rapid recovery from extinction to appear delayed. (a) Complete preservation: an extinction pulse at t_i−1 followed immediately by complete recovery (origination pulse) at t_i. (b) Uniform, incomplete preservation: assuming an exponential distribution of waiting times between a fossil’s apparent and true extinction (6), the pulse of extinction at t_i−1 (dark purple) is smeared over t_i−2 and t_i−3 (lighter purple); the analogous argument applies to origination (blue). Nonetheless, the origination distribution’s peak at t_i still immediately follows the extinction distribution’s peak at t_i−1, leaving temporal correlations qualitatively unchanged relative to the case of complete preservation. (c) Episodic, incomplete preservation: preservability in the time interval t_i immediately after an extinction at t_i−1 is often comparatively low (13), so that taxa that actually originated during t_i will be reported to have originated in t_i+1 and t_i+2. This drop in preservability at t_i further decreases the reported origination rate at t_i (blue arrow) while concomitantly increasing the apparent rates in t_i+1 and t_i+2 (white arrows), creating the artifactual temporal lag/delay in time of recovery from extinction that appears in Sepkoski’s data (13).