PhD: Dinosaur Functional Diversity and the Drivers of Dinosaurian Diversity

The Dinosauria are one of the most successful groups of animals ever to evolve. Originating over 200 million years ago, dinosaurs evolved a remarkable range of forms, including agile predators, heavily armed and armored plant eaters, long-necked browsers, and huge apex predators; dinosaurs also showed enormous variation in body size, ranging from just a few hundred grams to over 50 tonnes in weight. Their reign spanned some of the most important events in Earth’s history, including the eruption of the Central Atlantic Magmatic Province that initiated the Triassic-Jurassic mass extinctions, a series of major Jurassic and Cretaceous volcanic events, and the impact of the Chicxulub asteroid impact at 66 million years ago, which eliminated all dinosaurs except for a handful of birds (1). Given the diversity and longevity of the clade and their well-studied fossil record, they are an ideal study system for understanding major evolutionary questions. How do catastrophic events such as impacts and eruptions drive evolution? How do major biologic events such as the origin of flowers affect diversity? Is diversification a zero-sum game, or has terrestrial diversity increased over time?

Previous approaches to these problems face limitations. Taxon-counting (diversity curves) are subject to biases in preservation, sampling, and study, and it is unclear whether species richness is a reliable proxy for ecosystem structure and complexity. Morphometric approaches to disparity require relatively complete fossils, which are rare. Character-based approaches to disparity focus on discrete characters used for phylogenetic inference, which do not necessarily have ecological significance. A new approach, functional diversity (2), focuses on quantifying the range of functional traits or functional correlates. It is robust against sampling, can be conducted on incomplete fossils, and is known to tightly correlate with fundamental aspects of ecosystem structure such as primary productivity. Mesozoic dinosaurs represent an ideal model system for studying functional diversity of terrestrial animals.

The goal of this project will be to study the functional diversity of dinosaurs from 230 Ma to 66 Ma. Major questions include:
(I) was dinosaur diversity decreasing in the final 25 Ma of the Cretaceous preceding the Chicxulub impact?
(II) how did other events including Tr-J eruptions of the Central Atlantic Magmatic Province, OAE2, and angiosperm diversification drive dinosaur extinction and diversification?
(III) do patterns of dinosaur diversification suggest a long-term increase in terrestrial ecosystem diversity?
As part of our lab, the student will train in a variety of skills necessary for a research career in palaeontology, including description, taxonomy, phylogenetics, and quantitative methods. The project is designed to result in a series of significant research papers; opportunities for side projects developing other skills (e.g. descriptive palaeontology, describing new dinosaur taxa) will also be available. We believe that what separates the great science from the merely good science is not how we go about finding the answer, but the questions we choose to ask in the first place. In our lab, we focus on finding the right question- questions that are interesting, important, and solvable- and it is this focus on research design that guides our projects.
This project is also a part of a major, 5-year research project to understand mass extinction and post-extinction recoveries, specifically focusing on the K-Pg extinction, and so the student will join a large cohort of postgraduate students and postdocs. The University of Bath’s palaeontology group is young but growing rapidly, with two faculty (Dr. Nick Longrich and Prof. Matt Wills) being joined by a third member (Dr. Daniel Field) in 2017. The palaeontology group is in turn a key part of the new Milner Centre for Evolution, a unique research centre focused on doing groundbreaking research focusing on major problems in evolutionary biology.

Applicants should have strong research experience, although not necessarily in palaeontology; evidence of performance in the form of publications is desirable.

REFERENCES
1. Longrich, N.R., Tokaryk, T.T., Field, D., 2011. Mass extinction of birds at the Cretaceous-Paleogene (K-Pg) boundary. Proceedings of the National Academy of Sciences 108, 15253-15257.
2. Knope, M., Heim, N., Frishkoff, L., Payne, J., 2015. Limited role of functional differentiation in early diversification of animals. Nature Communications 6