PhD: Phylogeny and function of the basal sauropodomorph dinosaur Thecodontosaurus antiquus

The origin and early evolution of dinosaurs has been debated for decades. Fossils are sparse, and phylogenies sometimes conflict. There are profound macroevolutionary questions concerning the diversification of dinosaurs, the timing, the role of mass extinction events, feeding and locomotory adaptations, and how those early dinosaurs eventually replaced the therapsids as dominant medium-sized to large terrestrial tetrapods.

The basal sauropodomorph dinosaur Thecodontosaurus antiquus was named in 1836, and hundreds of bones were found at that time from quarries in Bristol, and redescribed by Benton et al. (2000). However, since then, many more bones have been extracted from fossiliferous rock from another location, and views on basal dinosaur phylogeny have changed. Late Triassic basal sauropodomorphs such as Thecodontosaurus were small (~2 m) and bipedal, yet into the early Jurassic, more derived sauropodomorphs (Massopoda) began evolving a more quadrupedal stance, enlarged body size (~3-6 m), and elongating and specializing their cervical and dorsal vertebrae. By studying Thecodontosaurus and other basal sauropodomorphs, we can begin to better understand why sauropods dramatically changed their life style and body form, and anatomically how such changes initially occurred. The student will describe the new materials, and complete the osteology of Thecodontosaurus, and produce a new whole-body reconstruction. There will be a particular focus on the vertebral column (with particular focus on the cervical and dorsal vertebrae), limbs, and pectoral and pelvic girdles. This will lead to a comparative study of other Late Triassic and Early Jurassic sauropodomorphs and a study of body size and posture, and especially how body size increased. Studies will explore the size and strength of leg bones, using engineering approaches and CT scans to explore bone microstructure and growth. Comparative studies will lead to a revised phylogenetic analysis, taking recent work on basal sauropodomorph phylogeny (e.g. Yates 2003) and updating it, and then comparing more widely with other recently described basal saurischians to resolve questions of the relationships of the basal clades, and when Saurischia split into Sauropodomorpha and Theropoda.

The project will provide training in vertebrate palaeontology, the interpretation, description and illustration of bones, phylogenetic methods, comparative biomechanical analysis, and numerical macroevolutionary methods. These are all a perfect training for a future career in vertebrate palaeontology research in a university or museum setting.