The rise and macro-evolution of crabs (Crustacea, Brachyura) during the Mesozoic

The present thesis provides new data on the evolution and palaeoecology of brachyuran crabs during the Cretaceous, with the emphasis on the Mesozoic Marine Revolution. A guild-based analysis, based on a detailed study of functional morphology, contributes to a broader understanding of macroevolutionary patterns within this group of decapod crustaceans during the MMR. By examining the evolutionary and ecological roles of brachyuran crabs within Mesozoic marine ecosystems, the current research features new insights into the drivers of diversification and specialisation. Here, I address these new data and insights through exploration of the research questions proposed in Chapter 1 (Introduction), and by using the results and interpretations presented in Chapters 2–10. 1. Can the ecological guild concept constitute an effective framework for understanding evolutionary and ecological adaptations of brachyuran crabs during the Mesozoic? My research concludes that the ecological guild concept constitutes a valuable and robust framework for understanding evolutionary and ecological adaptations of brachyuran crabs. By categorising crabs into guilds based on functional roles within the marine ecosystem and morphological traits, a better understanding of how brachyuran crabs interacted with their environment may be gained. The guild approach has proved particularly useful in identifying adaptive strategies and ecological niches, offering insights into the drivers of diversification and specialisation. However, the present study also acknowledges that there are limitations, such as the potential for oversimplification and the challenge of accounting for intra-guild variability. Overall, the guild concept may serve as a useful tool for the study of extinct brachyuran crabs, contributing significantly to the broader understanding of Mesozoic marine ecosystems and macroevolutionary processes. 2. How did the evolution and diversification of Mesozoic brachyuran crabs correlate with