Phylogenetic analyses of trilobites from the Cambrian and Ordovician radiations

Abstract

Trilobites are an ideal group used for phylogenetic studies due to their complex morphology and abundance in the Paleozoic fossil record. Because of this, trilobite phylogenetics has become an important component of understanding macroevolutionary patterns during key evolutionary radiations. Two radiations that this dissertation investigates are the Cambrian and Ordovician radiations. While both occur during the early Paleozoic, they present very different patterns. The Cambrian radiation was the sudden appearance of all major metazoan phyla, whereas in the Ordovician, those new beauplans were already in place and there was instead a great increase in diversity among those groups. Presented here are phylogenetic analyses of trilobites from those radiations to further our understanding of the evolutionary patterns occurring at those times.