Exploring evolution of feather function in early birds and dinosaurs

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Biologists understand the diversity of feather types and their functions in modern birds; however, extinct birds and related dinosaurspossessed all of these feather types, plus a dozen additional specialized morphologies. This recent discovery was unexpected andraises questions about overall evolution of feathers in a much wider group than simply birds (i.e. pterosaurs plus dinosaurs, includingbirds) and extending back 100 million years deeper in time than had been assumed before. This opens large questions around theinitial function of feathers, subsequent feather diversification and functions throughout pterosaurs, non-avian dinosaurs and birds,connections of such evolution to external environmental drivers (e.g. changing temperature, latitudinal distributions, atmosphericcomposition) as well as biological drivers such as competition and physiological innovation. We shall collect extensive data on feathermorphology, ultrastructure and inferred colours and patterns and assign these to species across a wide evolutionary tree, includingbirds, dinosaurs and pterosaurs, all groups that had feathers. The data will include a cross-section of modern birds, as well as manyfossil forms for which we have reliable data - now counting hundreds of species. Importantly, we will for the first time applycomputational phylogenetic comparative methods, both frequentist and Bayesian, to the data to determine timings of trait origins,rates of evolution, times of rapid innovation, and any correlations with potential drivers, including external physical drivers, bioticinteraction, and innovation. We will then compare feather types, considering all traits, and how these link to evo-devo understandingof genomic regulatory networks. The methods are new in the sense that they are still under improvement, but all have been usedwidely for a decade and so are generally regarded as trustworthy and feasible, offering a project of great novelty but controlled risk.