The role of cranial biomechanics and feeding in clade diversification and early dinosaur evolution

Novel anatomical adaptations and mechanisms for feeding are often postulated as 'key innovations' that spark the diversification of major clades. However, the mechanics of these adaptations are rarely quantitatively or rigorously tested, seriously undermining the validity of these hypotheses. Moreover, the majority of biomechanical analyses are carried out on single exemplar organisms, whereas a comparative phylogenetic context is critical to understanding the impact of feeding on evolutionary history and testing macroevolutionary hypotheses.

Dinosaurs dominated terrestrial ecosystems for >130 million years, exhibiting a tremendous range of body sizes, shapes and ecologies. The earliest dinosaurs and their ancestors were generalists and minor faunal components. Dramatic increases in body size, diversity and abundance occurred during the Late Triassic-Early Jurassic (230-180 million years ago), and various factors have been implicated in dinosaur success. It is thought that the appearance of novel feeding adaptations permitted ecological diversification. However, this engaging 'functional story' has not been tested in a quantitative, hypothesis-driven comparative framework and previous work has focused on derived dinosaur taxa with extreme morphologies (e.g., Tyrannosaurus, Diplodocus), ignoring forms close to the base of Dinosauria.

For these reasons, dinosaurs are an ideal model system for integrating data on feeding biomechanics with phylogeny, allowing more rigorous investigation of the relationship between functional diversity and clade dynamics. In this project we aim to comprehensively understand the consequences of functional changes in dinosaur skull biomechanics during the origin and early evolution of dinosaurs, a key moment in life's history. The proposed project is particularly timely given the availability and integration of cutting-edge computational methods for biomechanical analyses and new discoveries of early dinosaurs and their ancestors.

We will integrate principles and methods from palaeontology, biology and engineering to reconstruct skull anatomy and function in 15 early dinosaur and dinosauriform taxa. CT scans and visualization software will be used to create 3D computer models. Information from the original fossils and living crocodilians, birds and lizards will be used to reconstruct head musculature. Using these reconstructions and multi-body dynamics analysis, we will model jaw motions during feeding, estimate bite forces along the tooth row and calculate maximum jaw closing speed. We will integrate results from dynamic models with finite element analysis and geometric morphometrics to test how the skulls respond to feeding-induced loads. In addition, we will run simulations on three living species to ensure model predictions are accurate. Results from these analyses will provide evidence for the jaw function and potential diet of early dinosaurs, and whether they became more specialized in terms of feeding performance during their evolution. Finally, we will compare the appearance of feeding characters to dinosaur diversity patterns to determine what role feeding had in their early evolution and success.

Palaeontologists, anatomists, biomechanists, evolutionary biologists and engineers will benefit from this work, which will set new benchmarks for performing evolutionary biomechanics in living and fossil animals and will establish new UK, European and overseas collaborations. This project will also generate new methodological advances that can be applied to other clades and other functional questions. Finally, the technological and visual aspects of this work and its focus on early dinosaurs will appeal to the general public, offering numerous engagement opportunities and media interest that will contribute to increased public understanding of scientific principles and methods, and will ensure wide dissemination of this work.

Dinosaurs are tremendously popular with the public; however, attention is usually focused on later species that dominated life on Earth. General audiences are often surprised to learn that early dinosaurs were small, rare and shared their environment with other vertebrate groups. Moreover, people are fascinated by how scientists know how long-extinct animals lived. The primary aim of our impact plan is to educate and engage potential beneficiaries in early dinosaur palaeobiology, evolutionary processes, and new methods for understanding how animals work by showcasing exciting, cutting-edge UK science.

1. Who could potentially benefit from the proposed research?
The main non-academic beneficiaries of this research will be the general public (including children of various ages, adults and amateur scientists), educators, museums, and media organisations.

2. How might the potential beneficiaries benefit?
The general public will benefit from an enhanced understanding of how fossils help us understand evolutionary processes (including our own origins), how environmental changes impacted life in the past (and consider the implications of current environmental changes), and how methods from other disciplines such as mathematics and engineering are important for understanding how animals work. Fossil animals - especially dinosaurs - capture the imagination of the public and serve as a gateway to inspire audiences of all ages to better understand the world around them and the scientific principles underpinning it. Museum collections will benefit from enhanced knowledge and CT scans of their specimens, while museum exhibits and outreach programmes will benefit from new information on early dinosaurs and the evolution of feeding, as well as the project's highly visual results. The UK educational community will be another significant user of the information generated by this research, as it is of direct relevance to core topics in the National Curriculum for Science; specifically, teachers will receive new information for courses on biology and engineering to engage with their students. UK and international media organisations are key stakeholders given high levels of public interest in dinosaurs, natural history and science. Finally, this project will strengthen the UK's competitive advantage and its leading role in palaeobiology and animal biomechanics, result in lasting international partnerships and showcase how science is a multidisciplinary enterprise.

3. What will be done during and after the project to increase the likelihood of the research reaching the identified beneficiaries and maximise the likelihood of the identified benefits being achieved?
The greatest impact of the proposed project will be felt through the Natural History Museum's (NHM) public and educational outreach programmes. The NHM hosts over 5.4 million visitors per year and provides an excellent platform for broadcasting project results. We will contribute new information as well as interactive 3D digital models, videos from computer simulations and life-size physical models to NHM outreach and education programmes that cater to all ages and abilities. We will work closely with museum educators to identify and pursue opportunities for citizen science and volunteer programme tie-ins to the project, and support professional development of museum personnel. Working at the NHM will provide opportunities to present our research at venues across the UK, including regional fossil shows, amateur geological and natural history societies, and in NHM touring exhibitions. Distribution of digital dinosaur skulls and digital dissections of extant taxa through social media and a dedicated project website will extend this research programme's reach even further. Lastly, working closely with the NHM's proactive press office will ensure that project results are disseminated to the widest possible audience - see Pathways to Impact for further details on Point 3.