Enamel structure, development, and evolution in acrodont lizards

Project details

Supervisor: Dr Aaron LeBlanc

Mode of study: Full-time

Project/award duration: 1 October 2025 - 30 September 2029

Deadline for applications: 1 May 2025.

Expected start date: 1 October 2025 

Funding:

• Sponsor: Leverhulme Trust
• Stipend and/or bench fees (amount): £24,498.50/year
•  Tuition fees (Y/N): Y
• Funding includes support for research consumables, conference and research travel.

Eligibility:

Candidates who meet the eligibility criteria for Home fee status will be eligible to apply for this project. Home students will be eligible for a full award, including fees and stipend, if they satisfy the criteria below, including residency requirements. To be classed as a Home student, candidates must meet the following criteria:

-be a UK National (meeting residency requirements), or

-have settled status, or

-have pre-settled status (meeting residency requirements), or

-have indefinite leave to remain or enter.

Reference number: 2025/02/ALB/DOCS

Project description

Most reptiles can continuously replace their teeth throughout their lives, but a diverse group of lizards, known as the acrodonts, have lost this ability. Acrodont lizards cannot replace their adult teeth, similar to mammals, meaning that their teeth must be adapted to resist tooth wear for long periods of time. How their dental enamel, the most wear-resistant parts of their teeth, is adapted to suit the disparate diets of this diverse group of extant lizards is not known. This thesis project will therefore involve extensive histological sampling of enamel from representative species across seven subfamilies of acrodont lizards: Brookesiinae (leaf chameleons), Chamaeleoninae (chamaeleons), Leiolepidinae (butterfly lizards), Hydrosaurinae (sailfin lizards), Amphibolurinae (bearded dragons and their relatives), Agaminae (agamas), and Draconinae (gliding lizards and their relatives). This survey of extant acrodont species with disparate diets and ecologies will reveal for the first time how modern reptile enamel structure and chemistry can evolve to cope with the functional demands imparted on the dentition when the ability to replace teeth has been lost.

Histological analyses will be accomplished through CT scanning, hard-tissue histology, Scanning Electron Microscopy (SEM), and SEM-Energy Dispersive x-ray Spectroscopy (SEM-EDS). The student will also collect soft tissue data through paraffin sectioning and Transmission Electron Microscopy (TEM) of developing teeth in a select number of acrodont species. These will include close extant relatives of uromastycines, a group of acrodont lizards that evolved mammal-like enamel to determine how this stereotypically mammalian feature may have evolved from an ancestrally “simple” form of reptilian enamel.

The PhD student will work closely with a second PhD who specializes on the prismatic enamel of uromastycines. As such, the major findings from both projects will contribute to a comprehensive phylogenetic analysis, focusing on evolutionary changes in enamel structure, chemistry, and mechanical properties across acrodont lizards. This comparative phylogenetic methods approach will address the questions of (1) when; (2) how many times; and (3) under what ecological or functional scenarios different enamel structures are likely to appear within an evolutionary lineage. Moreover, comparisons of the mechanical properties of prismatic enamel with its prismless counterparts within other lizards will be used to test how the evolution of prismatic enamel may have contributed to the evolutionary success of acrodont lizards, or if it is associated with specific dietary and ecological niches.

Research training

·       Microscopy (light and electron microscopes)

·       Histology

·       CT scanning

·       Elemental analyses (Laser Ablation Mass Spectrometry, X-Ray Fluorescence)

·       Mechanical testing (micro- and nanoindentation)

·       Data analysis (statistical comparisons, phylogenetic comparative methods)

Person specification

·     Undergraduate or MSci degree in comparative anatomy, evolutionary biology, palaeontology, or similar qualification

·     Previous experience in phylogenetic analyses preferred

·     Interest and motivation in academic research

·     Interest in developing as an independent researcher

Next steps

Applicants are strongly encouraged to discuss the project with the first supervisor prior to submitting an application. 

Please apply online at apply.kcl.ac.uk following these steps:

1. Register a new account/login
2. Once logged in, select Create a new application
3. Enter ‘Dental and Health Sciences Research MPhil/PhD (Full-time)' under Choose a programme. Please ensure you select the correct mode of study
4. Select start date
5. Please note: Applicants must include the project reference number (2025/02/ALB/DOCS) in the 'Research proposal' and 'Funding (point 5)' sections of the application.

Contact for further information

Dr Aaron LeBlanc aaron.leblanc@kcl.ac.uk

Related Centre: Centre for Oral, Clinical & Translational Sciences

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