Paleozoic paleontology, with specialization in trilobites and other arthropods

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In order to illuminate Earth history during the Paleozoic Era (about 543 to 245 million years ago), I and my students collect and study invertebrate fossils. In particular, we collect trilobites and other arthropods as well as their traces, from a number of places around the world. We find, describe and illustrate spectacular new fossils, and then use details of their shapes, manners of preservation, diversity (numbers of species) and patterns of occurrence to create hypotheses about ancient events.  We select our field areas based upon where the fossils are best preserved and most abundant, but are poorly known. With these criteria, the information we discover is more important and novel. We reconstruct what the world looked like in the past, and how organisms interacted with each other and their environment. Another important aspect of our work is the analysis of the structures of these fossil organisms, using computers, in order to understand their relationships, based upon shared evolutionary advances, and create classification and naming schemes that reflect these relationships. This has led to the discovery of many new species and even genera or other higher categories. In the recent past, we have also discovered and described new skeletal structures in trilobites (eye shades) and in tabulate corals (spicules embedded in the soft tissues of their polyp animals). In a broader sense, we use the appearances and disappearances of the fossils in the rock sections to correlate the sections with one another and locate the horizons of episodes of mass extinction. We then study the rocks laid down during these times of extinction to find clues as to why these catastrophic events took place. If we can understand past levels of mass extinction, we may be able to avoid such catastrophies in the future. The work of my research group should substantially improve our knowledge of past organisms, and help us to understand why, when and where they evolved and then disappeared. The age correlations that we find between rocks of different regions are useful for understanding the time and space relationships between the rocks in those regions, and may have important economic applications in the exploration for hydrocarbon and mineral deposits.