Aspects of the post-Cretaceous recovery of the Cenozoic planktic foraminifera

Survivorship analysis was used to extract unbiased (censorship-corrected) estimates of the species longevity distribution of the Cenozoic planktic Foraminifera. These estimated distributions provide the basis for monte carlo simulations of the post Cretaceous recovery in the group. Using the achievement of a stable longevity distribution as a criterion for recovery yields a predicted recovery time of approximately 15 Myr. This prediction agrees well with the observed recovery time, but significant patterns of deviation from simulations suggest that extinction and origination rates covary and that rapid turnover during the Paleocene recovery period may have significantly reduced mean longevity during that time. A significant fit to a Weibull survivorship model suggests that there is an longevity-dependent increase in extinction probability which may be explained by temporal inhomogeneity in the origination rates of short-lived species. The scale of the inhomogeneity suggests it is unlikely to be an artifact of taxonomic practice or sampling error. Censorship-corrected mean longevity is reported to be 9.17 Myr.