Confidence Intervals on Stratigraphic Ranges When Recovery Potential Is Unknown

Several existing methods for estimating the true stratigraphic range of a fossil taxon require the assumption of uniform fossil recovery potential — that fossils are equally likely to be found at any point within the taxon's true range. This assumption is unrealistic, because factors such as the taxon's abundance and the amount of fossiliferous rock outcrop affect recovery potential. Other methods do not make this unrealistic assumption, but they instead require a priori quantitative knowledge of recovery potential that is often difficult to obtain. We present a method for estimating the true stratigraphic range of a taxon that works for both uniform and non-uniform recovery potential. In contrast to existing methods, we estimate fossil recovery potential from the data itself, so that a priori knowledge of recovery potential is not required. Using simulated datasets, we assess the performance of our method under a variety of conditions.