LEVERAGING THE COMBINED POWER OF PHYLOGENIES AND PALEOECOLOGY TO UNDERSTAND PATTERNS AND PROCESSES OF EVOLUTION IN THE FOSSIL RECORD (Invited Presentation)

The importance of both intrinsic biological and external environmental factors in defining macroevolutionary patterns has been recognized since its popularization by G. G. Simpson. However, there is still much discussion about how the genealogical and ecological hierarchies interact, and the general repeatability of the evolutionary outcome of any given situation. Of particular interest are the drivers of morphological innovation and whether novel morphologies are associated with shifts in Hutchinsonian niche. Phylogenetic paleoecology, combining tree-based frameworks of relationships with geologic paleoenvironmental data, is one way to explore how clades respond to broad-scale changes in environment. This talk will showcase multiple case studies from myself and my lab which illustrate the explanatory powers of these tree-based frameworks for paleoecological study. Tracking ecological changes across the evolutionary history of Xiphosurida reveals correlations between the origination of morphological novelty and ecological innovation as independent lineages occupy freshwater environments. Novelty originates through the onset of heterochronic trends as assessed by a weighting metric summarizing developmental trajectories across multiple morphological traits, the timing of which coincides with the shift to freshwater ecology. The Paleozoic bellinurines exhibit an overall paedomorphic trend, while the predominately Mesozoic austrolimulids follow a peramorphic trajectory. Studying ecological occupation within a phylogenetic framework provides a unique venue for evaluating macroevolutionary dynamics of evolutionary mode. Work within my lab demonstrates the utility of using phylogenetic paleoecology to study evolutionary transitions, including the evolution of sweep-feeding in eurypterids, ecological occupation among harpetid trilobites, and trends in environmental affinity among turritellid gastropods.