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 PIs and postdoctoral researcher Dr. Tracy Heath, starting at Iowa State as an assistant professor in January 2015, are developing and implementing 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 will also support the creation of two sets of on-line instructional exercises: one for junior high school biology students, and another for undergraduate paleontology students. More information on our project is provided at