Integrating Fossil Data into Likelihood-Based Phylogenetic Analyses with Trilobites as a Model System

Primary Researchers: Mark Holder and Bruce S. Lieberman

Fully integrating information from the fossil record into our understanding of evolutionary history requires a rigorous method for placing fossil taxa in their appropriate phylogenetic context.  The goal is to develop and implement models of discrete character evolution which will enable likelihood-based estimation of phylogenies of fossil and extant taxa.

In addition to improving the models for placing fossil taxa on phylogenies, we are extending methods for estimating speciation and extinction rates.  This work will be conducted in a Bayesian framework so that uncertainty in the shape of the phylogeny can be incorporated and will be very useful for testing a variety of macroevolutionary models. We are focusing on trilobites because of their exceptional diversity, their complex morphology which provides abundant potential characters, and the availability of a large number of phylogenetic datasets for the group. The inference procedures developed by this proposal will enable a much deeper synthesis of paleontological and neontological perspectives than is currently achievable.  The work also supported the creation of two sets of on-line instructional exercises, one for junior high school biology students, developed by Michelle Casey, Perry Kennard from Southwest Junior High School, Lawrence, KS, and Bruce S. Lieberman, accessible here:  and another, developed by Michelle Casey and Bruce S. Lieberman for undergraduate paleontology students, accessible here:   ;    ; and  . More information on our project is provided at