Collaborative Research: Bivalves in time and space: testing the accuracy of methods to reconstruct ancestral morphology, dates, geography, and diversification patterns

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This project seeks to develop bivalve molluscs as a preeminent model for evolutionary studies that span long periods of time. Evolutionary family trees (phylogenies) will be constructed for two families of bivalves, the cockles/giant clams and the pitarines, using a combination of DNA sequence data and morphology. These phylogenies will include 200 living and 100-200 extinct species and will be combined with computer simulations and the exceptional bivalve fossil record to test the accuracy of common methods in evolutionary estimation and reconstruction. Specifically, the project will test methods that use data from living species to estimate the ages, physical traits, and geographic distributions of ancestors throughout history. Nearly every aspect of modern comparative biology rests on the assumption that a phylogeny can be used to reconstruct the evolution of a variety of ancestral attributes. But reconstructions based on living species have broad uncertainties because the methods have not been tested against a precise history as represented in the fossil record. The bivalves are ideal for this effort because they are abundant today but also and have a rich fossil record. By using bivalves as a model to test all the major methods of reconstructing ancestral traits, ages, and distributions the results of this research will have far reaching impacts on fields as diverse as genomics, immunology, and ecology. As part of this effort the project will also train students from the high school to postdoctoral levels and will disseminate results broadly.