Paleobotany, evidence, and molecular dating: An example from the Nymphaeales

In recent years, most systematics studies have focused oil phylogenetic aualyses of molecular data sets. The latest trend has been to add molecular dating to these phylogenies Utilizing methods such as nonparametric rate smoothing (NPRS) and penalized likelihood (PL) and calibrating these analyses using (often only one or very few) fossils. The success of such approaches is dependent Oil several assumptions, including a local clocklike behaviour of evolution, the accuracy of the phylogeny, the Correct phylogenetic placement of fossils, and the consistency of particular fossils in extrapolating rates throughout a given phylogenetic free. An example of such all analysis of file Nymphaeales is provided to illustrate inappropriate use of fossils in this context and Faulty results based oil inadequate and/or inappropriate analyses. Neither fossil identifications nor a particular method of molecular dating should he called into question based on the disparity of a single analysis. Indeed, fossil observations and molecular dating are often at odds due to failure of the data to meet minimum assumptions of a clocklike behavior and poor or inadequate sampling of extant taxa, molecular sequence data, and/or fossils. Rejection or acceptance of either the fossils or the molecular dates resulting from their Use should he Considered ill light of direct analysis of the fossils and compared to other analyses using other fossils and/or Other extant, data sets. Rejection of fossils based oil unexpected results is merely verificationism.