Reconstructing the ecologies of Earth’s earliest arthropods

A major goal of palaeontology is having accurate and well-informed reconstructions of the ecology of ancient animals. This is key to our understanding of the broad-scale development of life on Earth and global ecosystems. Arthropods are the most abundant and diverse group of animals throughout Earth’s history, comprising >80% of described species, living across the globe, and displaying a broad range of morphologies that may represent the earliest adaptations to key ecological niches. The RECO-ECO project will test putative ecological adaptations of Earth’s earliest arthropods, clarifying how they dispersed globally and how they moved and fed in these environments >500 million years ago. I will achieve this by refining sophisticated Computational Fluid Dynamics simulations and the novel establishment of flume tank Experimental Fluid Dynamics. RECO-ECO has three Research Objectives: (1) Do morphologies of key extinct arthropods represent adaptations to a pelagic ecology? (2) How do extinct arthropod head shields interact with water and particle flow in feeding? (3) How do arthropod exoskeleton sclerites move and orientate in water and sediment flow regimes? Through answering these questions, I will reveal: (1) whether pelagic ecologies increased the dispersal capability of early arthropods, allowing them to dominate Earth’s oceans; (2) when key feeding ecologies evolved in arthropods and how they shaped ecosystem change; and (3) whether our fossil record palaeoecological interpretations are reliable or impacted by sedimentary flow processes. The need for robust palaeoecological hypothesis-testing is not unique to the arthropod fossil record and so the establishment of reliable and broadly applicable fluid dynamics methods will allow quantitative palaeoecological testing in other animal groups, revolutionising our ability to read ecologies of extinct animals from the fossil record and understand their impacts on ecosystem change throughout Earth’s history.