Elisabeth S. Vrba, the "Three Musketeers," and the Expansion of Macroevolutionary Theory

Elisabeth S. Vrba (1942-2025) was an important figure in paleobiology and evolutionary theory, leaving an indelible mark on macroevolutionary research. Vrba's collaboration with Stephen Jay Gould led to the introduction of the term "exaptation," refining how evolutionary biologists distinguish between traits originally selected for one function and those later co-opted for another; Gould and Vrba also clarified conceptual issues surrounding species sorting and selection, although they would later disagree on the meanings of species selection. Vrba further advanced, with Niles Eldredge, a hierarchical perspective on evolution, emphasizing cross-level causality. Her contributions to macroevolutionary theory, particularly through hypotheses advanced by herself, for example, the Effect Hypothesis, the Resource-Use Hypothesis and the Mass-Heterochrony Hypothesis, underscored the role of environmental pressures in shaping biodiversity. Vrba's contribution, which advanced and defined the field of macroevolution, is one of rigorous theoretical innovation, and more importantly empirical integrative testing using approaches from community ecology, developmental dynamics, and the paleoclimatology of species turnover patterns at large temporal and spatial scales, influencing not only paleontology but evolutionary biology at large. As we bid farewell to one of the field's most influential thinkers, we recognize the lasting impact of her work on how we understand the history of life. Additionally, we highlight points of harmony and disagreement between Vrba, Gould and Eldredge, which we consider mostly missing from historical literature.