The Phylogenetic Relationships and Ecomorphological Diversification of Early Crocodylomorphs

The diversity of organisms on Earth is unevenly distributed across time and the tree of life. An understanding of the dynamics and processes underpinning this observation is one of the central questions in the field of evolutionary biology. Crocodylomorphs, a group of pseudosuchian archosaurs that includes crocodilians and their extinct relatives, exhibit limited taxonomic and morphological diversity in the present day; however, extant forms represent only a fraction of the diversity achieved by the group throughout their around 230-million-year history. Crocodylomorphs have occupied a variety of ecologies, evolved a disparate range of morphologies, and survived two mass extinction events. This makes them an excellent system through which to study macroevolutionary processes; however, a well-resolved phylogeny is necessary to be able to effectively do so. Within Crocodylomorpha, the evolutionary relationships of 'early crocodylomorphs' ("Shenosuchia" + Protosuchia) are poorly known, as is the position of the thalattosuchians. As such, this project will seek to address this issue through the construction and analysis of a new phylogenetic dataset, including the development of an illustrated character list. This project will incorporate data from first-hand observation of a wide range of taxa and utilise CT scanning technology to study and characterize the internal anatomy of specimens. The resultant phylogeny will be applied, conducting cranial and post-cranial disparity analyses to better understand the group's ecomorphological radiation across the Triassic/Jurassic boundary. Doing so will allow for extinction selectivity and resilience to mass extinction events to be determined, with potential implications for present-day conservation efforts.