Project highlights

  • Use new techniques to shed fresh light on a long-standing evolutionary question – the diversity of mammals after the extinction of dinosaurs
  • Acquire a suite of skills for quantitative statistical analysis of textures, morphology and evolutionary patterns
  • Opportunities to travel to collect data from fossil collections across Europe and the US, and conduct fieldwork in New Mexico

 

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 new approach rarely applied to mammals of this age: dental microwear texture analysis (DMTA). The application of this approach 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 the University of 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.

 

Host

University of Leicester

Theme

  • Organisms and Ecosystems

Supervisors

Project investigator

  • Prof. Mark Purnell, University of Leicester

Co-investigators

  • Dr Stephen Brusatte, University of Edinburgh
  • Dr Thomas Williamson, New Mexico Museum of Natural History
  • Prof Sarah Gabbott, University of Leicester.

How to apply

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 Microwear texture analysis using multivariate methods developed at the University of Leicester (Purnell et al. 2013, Gill et al. 2014). Combining this with mesowear analysis, isotopic data, functional morphological analysis, 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 transitions that predate and potentially drive morphological adaptation of teeth to new functional roles.

Training and skills

Specialist training will include tooth microwear analysis, techniques for phylogenetic testing and analysis of macroevolutionary patterns, and tooth shape analysis. The emphasis will be on robust quantitative analysis and statistical hypothesis testing.

Partners and collaboration

Prof. Mark Purnell leads research on quantitative tooth microwear at Leicester and has developed new applications of the techniques to a variety of vertebrates, including small insectivores and primitive mammals. Dr Stephen Brusatte has published widely on fossil mammals and dinosaurs, and has extensive experience in the application of phylogenetic inferences and quantitative approaches to analysis of palaeontological data. Dr Thomas Williamson is an expert on Cretaceous and Palaeocene vertebrates, particularly from the San Juan Basin of New Mexico.

 

Further details

Any questions? Contact Mark Purnell, University of Leicester, mark.purnell@le.ac.uk

http://www.le.ac.uk/people/map2

https://le.ac.uk/study/research-degrees/funded-opportunities/centa-phd-studentships

Possible timeline

Year 1

Basic research skills training; familiarisation with literature, existing datasets and tooth microwear techniques. Collection and analysis of tooth microwear data in extant comparator taxa following visits to collections in UK, Europe, and USA. Possible fieldwork in New Mexico.

Year 2

Complete collection and analysis of tooth microwear in fossil mammals following visits to collections, particularly in USA. Mesowear, shape and functional morphological analysis, and integration of isotopic data.

Year 3

Synthesis of results and analysis of diet in phylogenetic and macroevolutionary context. Writing the thesis will take place during the final year, but papers will be published throughout the project. There will also be opportunities to give presentations at international meetings in the UK and overseas.

 

Further reading

Close RA, Friedman M, Lloyd GT, & Benson RB (2015) Evidence for a Mid-Jurassic Adaptive Radiation in Mammals. Current biology: CB 25(16):2137-2142.

Gill PG, Purnell MA, et al. (2014) Dietary specializations and diversity in feeding ecology of the earliest stem mammals. Nature 512:303-305.

Grossnickle, DM., SM Smith & GP Wilson 2019: Untangling the Multiple Ecological Radiations of Early Mammals. Trends Ecol Evol, 34, 936-949.

Purnell MA, Crumpton N, Gill PG, Jones G, & Rayfield EJ (2013) Within-guild dietary discrimination from 3-D textural analysis of tooth microwear in insectivorous mammals. J. Zool. 291(4):249-257.

Williamson TE, Brusatte SL, Secord R, & Shelley S (2015) A new taeniolabidoid multituberculate (Mammalia) from the middle Puercan of the Nacimiento Formation, New Mexico, and a revision of taeniolabidoid systematics and phylogeny. Zool. J. Linn. Soc.

Wilson GP, et al. (2012) Adaptive radiation of multituberculate mammals before the extinction of dinosaurs. Nature 483(7390):457-460.

COVID-19

The University of Leicester has clear and effective guidelines and risk assessments that have allowed for safe overseas data collection during the pandemic where it is essential for PhD research to progress. If prevailing conditions during this project prevent research visits to US collections, arrangements are in place for material to be shipped to Leicester. Combined with the potential for major data collecting trips to be carried out in year 2 of the project, the impact of COVID-19 on the research can be mitigated.