Dining after the dinosaurs? Dietary diversity and niche partitioning in Palaeocene mammals

Overview
This project will use new techniques to address one of the perennial questions in palaeontology: the impact of dinosaurs and their extinction on mammal evolutionary history. A number of recent studies have focussed on the timing of mammal diversification (e.g. Wilson et al. 2012, Close et al. 2015, Grossnickle 2019), but it is more difficult to test hypotheses of ecological diversity. Morphological analysis of well-preserved articulated mammal skeletons of Jurassic age is starting to paint a picture of mammals occupying a broader range of ecological niches than previously thought, but the majority of fossil mammals are known only from disarticulated remains and teeth, and are not amenable to this type of functional analysis. Consequently, the degree to which their ecological diversity was affected by the K-Pg extinction, and the pattern of ecological diversification during the Palaeocene, have been difficult issues to address.
This project will employ a powerful new approach, analysis of Dental Microwear Texture (DMT), the application of which to early mammals was pioneered by the supervisors (Purnell et al. 2013, Gill et al. 2014). You will combine this with other dietary proxies (isotopic data, mesowear and quantitative shape analysis of teeth) in phylogenetic context, to conduct multidisciplinary, multiproxy investigation of the dietary diversity of Palaeocene mammals, and of the patterns of trophic niche occupation and partitioning. You will establish the dietary guilds to which the early members of modern mammal lineages belong. DMTA has revealed hidden trophic diversity in Jurassic mammals, indicating that lineage splitting during the earliest stages of mammalian evolution was associated with ecomorphological specialization and niche partitioning (Gill et al. 2014). This project, applying the approach to Palaeocene fossils, will similarly yield new insights into the evolutionary history of mammals.
This project is ideal for applicants with a first degree in geological or biological sciences and an aptitude for quantitative analysis. At Leicester you will join a dynamic group of researchers, PhD and Masters students working on novel analyses of diet and trophic niche in fossil vertebrates.
Methodology: The project will focus on material from the San Juan Basin of New Mexico - one of the world's premier localities for Palaeocene mammal fossils. The collections, held in the New Mexico Museum of Natural History, include new material recently excavated by the supervisors, and the project offers opportunities for fieldwork in New Mexico. Dietary analysis will employ quantitative 3D Dental Microwear Texture Analysis using multivariate methods developed at Leicester (Purnell et al. 2013, Gill et al. 2014). Combining this with analysis of tooth mesowear, isotopic data, dental topography, functional morphology, and quantitative phylogenetic methods will allow robust analysis and hypothesis testing of the role of feeding and diet at different temporal and spatial scales. This approach will allow independent testing of dietary hypotheses, and evaluation of specific roles within broader dietary guilds, and has the potential to pick up dietary transtions that predate and potentially drive morphological adaptation of teeth to new functional roles.
Training and skills:
Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and 'free choice' external training. One CTC equates to 0.5 day session and students must accrue 100 CTCs across the three years of their PhD.
Specialist training will include dental microwear texture analysis, dental topographic analysis, techniques for phylogenetic testing and analysis of macroevolutionary patterns, and anatomical analysis of Cretaceous-Paleogene mammals. The emphasis will be on robust quantitative analysis and statistical hypothesis testing.