The evolutionary history of the ceratopsian ‘horned’ dinosaurs

Background

The ceratopsian ‘horned’ dinosaurs are a clade of ornithischian ‘bird-hipped’ dinosaurs characterized by elaborate frills and horns that adorn their skulls. Early members of the group are bipeds and quadrupeds known from Early Cretaceous deposits of North America and Asia.

The major radiation of ceratopsids are almost exclusively North American and are known from the Late Cretaceous; they include some of the most iconic dinosaurs, such as Triceratops. Ceratopsians have an excellent fossil record, with complete, articulated skeletons known for some species (e.g. Chasmosaurus, Anchiceratops), and hundreds of specimens known for others (Centrosaurus, Pachyrhinosaurus).

However, phylogenetic relationships in the clade are unclear because relationships have only been quantitatively analysed within sub-clades to date, and an analysis of the whole group has never been carried out. Furthermore, existing analyses focus almost entirely on characteristics of the skull, and ignore postcrania, although there is no a priori reason to consider that the skull holds more phylogenetic information than the postcranial skeleton.

The lack of a whole-group phylogeny for Ceratopsia hinders our understanding of their evolution and palaeobiology, because character states at the base of the ceratopsid radiation are unpolarised. Such characters are important for our understanding of the evolution of quadrupedality and locomotor mode, complex chewing mechanisms, and the development and function of the iconic horns and frills characteristic of these dinosaurs.

Project Aims and Methods

The aim of this project is to build a total-group ‘supermatrix’ phylogeny of ceratopsian dinosaurs, and use it to examine macroevolution and palaeobiogeography in the group.

The project will take existing sub-clade matrices, combine them, and then build on them by adding postcranial characters based on first-hand observations of ceratopsian dinosaur specimens in museum collections in Asia and North America.

Analysis of the resulting character-taxon matrix will produce the first ever whole-group phylogeny of Ceratopsia. Diversity, disparity, and rates of evolution can then be analysed to assess hypotheses about radiation and competition within ceratopsid sub-clades.

Maximum-likelihood methods will be used to analyse the palaeobiogeographic history of the clade, and hence to test hypotheses of endemicity. Finally, ancestral character states could be reconstructed using parsimony and maximum-likelihood; this will elucidate the evolution of quadrupedality, complex chewing mechanisms, and the function of the frills and horns.

The exact questions and analytical methods to be used will be determined by the student’s interests. 

Eligibility

To be eligible for a full award a student must have:

• British Citizenship or; 
  
• Settled status in the UK, meaning they have no restrictions on how long they can stay,
• Been ‘ordinarily resident’ in the UK for 3 years prior to the start of the studentship - (For non-EU citizens, this must NOT have been in full time education.)
  This means they must have been normally residing in the UK (apart from temporary or occasional absences).  This does not apply to UK nationals. 

Applicants should have obtained, or be about to obtain, a first- or upper second-class UK Honours degree, or the equivalent qualifications gained outside the UK. Applicants with a lower second-class degree will be considered if they also have a master’s degree or relevant professional experience.

How to apply

Applications for the PhD are processed through the Natural History Museum.

To apply please send the following documents to the Postgraduate Office at postgradoffice@nhm.ac.uk:

• Curriculum vitae.
• Covering letter outlining your interest in the PhD position, relevant skills training, experience and qualifications for the research, and a statement of how this PhD project fits your career development plans.
• Names of two academic referees.

The deadline for applications is 6 January 2020.