Overview

Some of the worlds most important fossils of small-bodied Late Triassic and Early Jurassic vertebrates come from the famous fissure fill deposits of southwest England and south Wales, and have provided critical insights into the origins of major groups, including dinosaurs, and the impact and response to the end-Triassic mass extinction. Among the best-preserved fossils are some of the world’s oldest and most primitive crocodylomorphs (the group including crocodilians and their immediate fossil relatives). These include the holotype and referred specimens of the small (up to 1 metre in length) crocodylomorph Terrestrisuchus gracilis, a terrestrial species with greyhound-like body proportions completely unlike those of modern crocodilians. Additional undescribed crocodylomorph specimens, some of which may represent new species, are known from a number of other localities.

The main aim of this project is to conduct a comprehensive anatomical, systematic and phylogenetic study of all of the crocodylomorph fossils from the British Mesozoic fissure fill deposits, utilising modern imaging techniques including micro-CT scanning. Key research questions include: (1) How many crocodylomorph species are present in the various fissures? Does all of the material represent Terrestrisuchus gracilis, or are additional, as-yet-undescribed, species also present? (2) Where do the fissure fill taxa within the evolutionary tree (phylogeny) of crocodylomorphs, and what does that imply about the origin and radiation of this important group, and the construction of the crocodylomorph body plan? (3) How did the British crocodylomorphs change as they matured from juveniles into adults and how quickly did they grow compared to living crocodiles? (4) How were crocodylomorphs affected by the end-Triassic extinction, how many lineages made it through, and how many lineages were lost?   

 

Reconstruction of Late Triassic southwest England, with the early crocodylomorph Terrestrisuchus carrying a freshly killed sphenodontian (from Fraser 2006; artwork by Douglas Henderson).

Methodology

The student will visit important fossil collections in the UK and the USA to examine the entirety of collected crocodylomorph fissure fill material from the Triassic-Jurassic of England and Wales. Selected specimens will be micro-CT scanned, and specialist software will be used to complete virtual 3D reconstructions of key anatomical regions (e.g. the skull). Additional visits to overseas collections (e.g. in North America, Europe, and South Africa) will allow the student to observe a wide range of comparative early crocodylomorph fossil material.

The student will build a comparative database of photos, measurements, and anatomical data for early crocodylomorphs, and will use this data to complete comprehensive anatomical descriptions, to assess the taxonomy of the fissure fill specimens, and to document patterns of ontogenetic and individual variation. These data will be used to construct a morphological character dataset for phylogenetic analysis, which will be analysed using parsimony and Bayesian approaches to elucidate the evolutionary relationships of the fissure fill material and its implications for understanding broader patterns of early crocodylomorph phylogeny. Finally, the anatomical and phylogenetic datasets will be used to quantify patterns of crocodylomorph species richness and morphological diversity (disparity) across the end-Triassic extinction event and subsequent Jurassic recovery. 

Training and Skills

CENTA students are required to complete 45 days training throughout their PhD including a 10-day placement. In the first year, students will be trained as a single cohort on environmental science, research methods and core skills. Throughout the PhD, training will progress from core skills sets to master classes specific to the student's projects and themes. 

Comprehensive project-specific training will be provided and will include vertebrate anatomy, how to describe and photograph fossil specimens, generation and analysis of CT data (including using popular CT software, such as Avizo), building and using comparative databases, using various quantitative approaches to build phylogenies and test evolutionary trends over time (including coding in R), international scientific collaborations, and public communication of science. Opportunities may also be available for the student to gain teaching and project supervision experience through the undergraduate programmes in Earth Sciences at Birmingham, as well as to gain skills in finding and collecting fossils in the field, through the lead supervisor’s active international fieldwork programme.   

Timeline

Year 1: Training in vertebrate anatomy, taxonomy, phylogenetics and analysis of CT data. CT scanning of key specimens. Data collection trips to UK museums. Work on anatomical descriptions and taxonomic revisions. Conferences: SVPCA (UK), EAVP (Europe).

Year 2: Virtual reconstructions of CT data. Collection of comparative anatomical information from overseas museum collections. Completion of anatomical descriptions and taxonomic revisions. Submission of first publications. Conferences: SVPCA (UK), EAVP (Europe).   

Year 3: Completion of CT work. Development and analysis of phylogenetic dataset. Quantitative analyses of species richness and disparity of crocodylomorphs through time. Ongoing publication of results. Write up and submision of thesis. Conferences: SVPCA (UK), SVP (USA).      

 

Partners and collaboration (including CASE)

The core Birmingham supervisory team will consist of Professor Richard Butler and Dr Stephan Lautenschlager. Butler is a leading expert on the anatomy, systematics and evolution of Triassic archosaurs, and has extensive experience in the application of quantitative approaches to analysis of palaeontological data. Lautenschlager has pioneered the use of digital methods such as micro-CT scanning to restore fossil morphology and to reconstruct soft-tissue anatomy. Additional expertise and access to key fossil specimens and collections will be provided by the external supervisors, Professor Paul Barrett (Natural History Museum, London), Dr Stephen Brusatte (University of Edinburgh) and Dr Nicholas Fraser (National Museums Scotland). The supervisory team has a wide international network of collaborators that will facilitate access to fossil material worldwide.   

Further Details

Please contact Professor Richard Butler (r.butler.1@bham.ac.uk) for further details.